® ® ASTRO Digital Spectra and Digital Spectra Plus UHF/VHF/800 MHz Mobile Radios Detailed Service Manual
Foreword This manual provides sufficient information to enable qualified service technicians to troubleshoot and repair ASTRO® Digital Spectra® and ASTRO Digital Spectra Plus mobile radios (models W3, W4, W5, W7, and W9) to the component level. For the most part, the information in this manual pertains to both ASTRO Digital Spectra and ASTRO Digital Spectra Plus radios. Exceptions are clearly noted where they occur.
Table of Contents Foreword .........................................................................................................ii Product Safety and RF Exposure Compliance ............................................................................................ii Manual Revisions ........................................................................................................................................ii Computer Software Copyrights .......................................................
iv Table of Contents Chapter 2 General Overview................................................................ 2-1 2.1 2.2 2.3 2.4 Introduction .................................................................................................................................... 2-1 Analog Mode of Operation ............................................................................................................. 2-2 ASTRO Mode of Operation...............................................................
Table of Contents 3.3 3.4 3.5 v 3.2.4 Regulators ...................................................................................................................... 3-10 3.2.5 Reset Circuits ................................................................................................................. 3-10 3.2.6 Serial Communications on the External Bus .................................................................. 3-11 3.2.7 Synchronous Serial Bus (MOSI) ......................................
vi Table of Contents 3.6 3.7 3.5.2.9 Doubler .................................................................................................................. 3-50 3.5.2.10 Synthesizer Feedback ........................................................................................... 3-50 3.5.2.11 Second Buffer ........................................................................................................ 3-50 3.5.2.12 Receive/Transmit Switch ..................................................
Table of Contents Chapter 4 4.1 4.2 4.3 4.4 4.5 vii Troubleshooting Procedures ............................................. 4-1 ASTRO Spectra Procedures.......................................................................................................... 4-1 4.1.1 Handling Precautions........................................................................................................ 4-1 4.1.2 Voltage Measurement and Signal Tracing.............................................................
viii Table of Contents 4.5.1.3.1 General Troubleshooting and Repair Notes ................................................... 4-38 4.5.1.3.2 PA Functional Testing..................................................................................... 4-39 4.5.1.3.3 Localizing Problems........................................................................................ 4-42 4.5.1.3.4 Isolating Failures............................................................................................. 4-43 4.5.1.
Table of Contents ix ASTRO Spectra Plus VOCON DC Supply Failure ................................................................ 5-20 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 1 of 4...................................... 5-21 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 2 of 4 ...................................... 5-22 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 3 of 4...................................... 5-23 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 4 of 4 ......
x Table of Contents 7.2 7.3 7.4 7.5 HRN4009E and HRN6014D VHF RF Board; HRN4010D and HRN6020C UHF RF Board; and HRN6019C 800 MHz RF Component Location Diagram ...................................................... 7-14 Command Board Section............................................................................................................. 7-17 HLN5558E/F/G, HLN6529C/D/E/F/G, HLN6560C/D/E/F/G/H and HLN6562C/D/E/F/G/H Command Board Schematic Diagram .............................................
Table of Contents 7.6 7.7 xi HLF6080B 800 MHz VCO Component Location Diagram .................................................... 7-80 RX Front-End Section.................................................................................................................. 7-82 HRD6001E/6002E/6011E/6012E VHF Receiver Front-End Schematic ................................ 7-82 HRD6001E/6002E/6011E/6012E VHF Component Location Diagram .................................
xii Table of Contents Appendix B Replacement Parts Ordering..............................................B-1 B.1 B.2 B.3 B.4 B.5 B.6 B.7 B.8 Basic Ordering Information ............................................................................................................B-1 Transceiver Board and VOCON Board Ordering Information........................................................B-1 Motorola Online....................................................................................................
List of Figures xiii List of Figures Figure 2-1. DC Voltage Routing Block Diagram ...................................................................................... 2-9 Figure 2-2. ASTRO Spectra B+ Routing for Vocoder/Controller (VOCON) Board ................................ 2-10 Figure 3-1. Prescaler IC Block Diagram.................................................................................................. 3-2 Figure 3-2. Synthesizer IC Block Diagram ...........................................
xiv List of Tables List of Tables Table 3-1. Table 3-2. Table 3-3. Table 3-4. Table 3-5. Table 3-6. Table 3-7. Table 3-8. Table 3-9. Table 4-1. Table 4-2. Table 4-3. Table 4-4. Table 4-5. Table 4-6. Table 4-7. Table 4-8. Table 4-9. Table 4-10. Table 4-11. Table 4-12. Table 4-13. Table 4-14. Table 4-15. Table 4-16. Table 4-17. Table 4-18. Table 4-19. Table 4-20. Table 4-21. Table 4-22. Table 4-23. Table 4-24. Table 4-25. Table 5-1. Table A-1. Table A-2. Integrated Circuits Voltages .......................
Commercial Warranty Limited Warranty MOTOROLA COMMUNICATION PRODUCTS I. What This Warranty Covers And For How Long MOTOROLA INC.
xvi Commercial Warranty III. State Law Rights SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LIMITATION ON HOW LONG AN IMPLIED WARRANTY LASTS, SO THE ABOVE LIMITATION OR EXCLUSIONS MAY NOT APPLY. This warranty gives specific legal rights, and there may be other rights which may vary from state to state. IV.
Commercial Warranty xvii VI. Patent And Software Provisions MOTOROLA will defend, at its own expense, any suit brought against the end user purchaser to the extent that it is based on a claim that the Product or parts infringe a United States patent, and MOTOROLA will pay those costs and damages finally awarded against the end user purchaser in any such suit which are attributable to any such claim, but such defense and payments are conditioned on the following: A.
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Model Numbering, Charts, and Specifications xix Model Numbering, Charts, and Specifications Mobile Radio Model Numbering Scheme Typical Model Number: T Position: 1 0 2 4 3 S 4 L 5 Position 1 - Type of Unit D = Dash-Mounted Mobile Radio M = Motorcycle Mobile Radio T = Trunk-Mounted Mobile Radio 9 7 P 8 W 9 7 10 A 11 N 12 S 13 P 14 0 15 1 16 Positions 13 - 16 SP Model Suffix Position 12 Unique Model Variations C = Cenelec N = Standard Package Positions 2 & 3 - Model Series 04 = ASTRO Posit
xx Model Numbering, Charts, and Specifications ASTRO Digital Spectra Motorcycle 15 Watt (Ranges 1 and 2) Model Chart Model Number Description M04JGF9PW4AN M04JGF9PW5AN M04JGH9PW7AN M04KGF9PW4AN M04KGF9PW5AN M04KGH9PW7AN M04RGF9PW4AN M04RGF9PW5AN M04RGH9PW7AN M04UGF9PW4AN M04UGF9PW5AN M04UGH9PW7AN Model W4 (136-162 MHz), Range 1, 15 Watt, 128 Channels Model W5 (136-162 MHz), Range 1, 15 Watt, 128 Channels Model W7 (136-162 MHz), Range 1, 15 Watt, 128 Channels Model W4 (146-174 MHz), Range 2, 15 Watt, 12
Model Numbering, Charts, and Specifications xxi ASTRO Digital Spectra Motorcycle 15 Watt (Ranges 3 and 3.5) Model Chart Model Number M04RGF9PW4ANSP02 M04RGF9PW5ANSP02 M04RGF9PW4ANSP01 M04RGF9PW5ANSP01 M04RGH9PW7ANSP01 Item No.
xxii Model Numbering, Charts, and Specifications ASTRO Digital Spectra VHF 10–25 Watt Model Chart Model Number Description D04JHH9PW3AN D04JHF9PW4AN D04JHF9PW5AN D04JHH9PW7AN T04JHH9PW9AN D04KHH9PW3AN D04KHF9PW4AN D04KHF9PW5AN D04KHH9PW7AN T04KHH9PW9AN Model W3 (136-145.
Model Numbering, Charts, and Specifications xxiii ASTRO Digital Spectra VHF 10–25 and 50–110 Watt Model Chart Model Number Description D04JKH9PW3AN D04JKF9PW4AN D04JKF9PW5AN D04JKH9PW7AN T04JKH9PW9AN D04KKF9PW3AN D04KKF9PW4AN D04KKF9PW5AN D04KKH9PW7AN T04KKH9PW9AN T04JLH9PW3AN T04JLF9PW4AN T04JLF9PW5AN T04JLH9PW7AN T04JLH9PW9AN T04KLH9PW3AN T04KLF9PW4AN T04KLF9PW5AN T04KLH9PW7AN T04KLH9PW9AN Model W3 (136-145.
xxiv Model Numbering, Charts, and Specifications ASTRO Digital Spectra VHF 10–25 and 50–110 Watt Model Chart (cont.) Model Number Description D04JKH9PW3AN D04JKF9PW4AN D04JKF9PW5AN D04JKH9PW7AN T04JKH9PW9AN D04KKF9PW3AN D04KKF9PW4AN D04KKF9PW5AN D04KKH9PW7AN T04KKH9PW9AN T04JLH9PW3AN T04JLF9PW4AN T04JLF9PW5AN T04JLH9PW7AN T04JLH9PW9AN T04KLH9PW3AN T04KLF9PW4AN T04KLF9PW5AN T04KLH9PW7AN T04KLH9PW9AN Model W3 (136-145.
Model Numbering, Charts, and Specifications xxv ASTRO Digital Spectra UHF 10–25 Watt Model Chart Model Number D04RHH9PW3AN D04RHF9PW4AN D04RHF9PW5AN D04RHH9PW7AN T04RHH9PW9AN Item No.
xxvi Model Numbering, Charts, and Specifications ASTRO Digital Spectra UHF 20–40 Watt Model Chart Model Number Description D04QKH9PW3AN D04QKF9PW4AN D04QKF9PW5AN D04QKH9PW7AN T04QKH9PW9AN D04RKH9PW3ANSP01 D04RKF9PW4AN D04RKF9PW5AN D04RKH9PW7AN T04RKH9PW9AN D04SKH9PW3AN D04SKF9PW4AN D04SKF9PW5AN D04SKH9PW7AN T04SKH9PW9AN Model W3 (403-433 MHz), 20-40 Watt, 128 Channels Model W4 (403-433 MHz), 20-40 Watt, 128 Channels Model W5 (403-433 MHz), 20-40 Watt, 128 Channels Model W7 (403-433 MHz), 20-40 Watt, 25
Model Numbering, Charts, and Specifications xxvii ASTRO Digital Spectra UHF 20–40 Watt Model Chart (cont.
xxviii Model Numbering, Charts, and Specifications ASTRO Digital Spectra UHF 50–110 Watt Model Chart Model Number Description T04QLF9PW4AN T04QLF9PW5AN T04QLH9PW7AN T04QLH9PW9AN T04RLF9PW4AN T04RLF9PW5AN T04RLH9PW7AN T04RLH9PW9AN T04SLF9PW4AN T04SLF9PW5AN T04SLHPW7AN T04SLHPW9AN Item No.
Model Numbering, Charts, and Specifications xxix ASTRO Digital Spectra UHF 50–110 Watt Model Chart (cont.) Model Number Description T04QLF9PW4AN T04QLF9PW5AN T04QLH9PW7AN T04QLH9PW9AN T04RLF9PW4AN T04RLF9PW5AN T04RLH9PW7AN T04RLH9PW9AN T04SLF9PW4AN T04SLF9PW5AN T04SLHPW7AN T04SLHPW9AN Item No.
xxx Model Numbering, Charts, and Specifications ASTRO Digital Spectra 800 MHz Model Chart Model Number D04UJF9PW3AN D04UJF9PW4AN D04UJF9PW5AN D04UJF9PW7AN T04UJF9PW9AN Item No.
Model Numbering, Charts, and Specifications xxxi ASTRO Digital Spectra Plus VHF 25–50 and 50–110 Watt Model Chart Model Number Description D04KKH9SW3AN D04KKF9SW4AN D04KKF9SW5AN D04KKH9SW7AN T04KKH9SW9AN T04KLH9SW3AN T04KLF9SW4AN T04KLF9SW5AN T04KLH9SW7AN T04KLH9SW9AN Model W3 (146-174 MHz), 25-50 Watt, 512 Channels Model W4 (146-174 MHz), 25-50 Watt, 128 Channels Model W5 (146-174 MHz); 25-50 Watt, 128 Channels Model W7 (146-174 MHz),25-50 Watt, 512 Channels Model W9 (146-174 MHz), 25-50 Watt, 512 Cha
xxxii Model Numbering, Charts, and Specifications ASTRO Digital Spectra Plus VHF 25–50 and 50–110 Watt Model Chart (cont.
Model Numbering, Charts, and Specifications xxxiii ASTRO Digital Spectra Plus 800 MHz Model Chart Model Number Description M04UGF9SW4AN M04UGF9SW5AN M04UGH9SW7AN D04UJH9SW3AN D04UJF9SW4AN D04UJF9SW5AN D04UJH9SW7AN T04UJH9SW9AN Item No.
xxxiv Model Numbering, Charts, and Specifications ASTRO Digital Spectra Plus 800 MHz Model Chart (cont.) Model Number Description M04UGF9SW4AN M04UGF9SW5AN M04UGH9SW7AN D04UJH9SW3AN D04UJF9SW4AN D04UJF9SW5AN D04UJH9SW7AN T04UJH9SW9AN Item No.
Model Numbering, Charts, and Specifications xxxv VHF Radio Specifications GENERAL FCC Designations: RECEIVER AZ492FT3772 AZ492FT3773 Frequency Range: Range 1: Range 2: TRANSMITTER 136–162 MHz 146–174 MHz Frequency Range: Range 1: Range 2: 136–162 MHz 146–174 MHz Temperature Range: Operating: Storage: –30°C to +60°C –40°C to +85°C Power Supply: Channel Spacing: 12.
xxxvi Model Numbering, Charts, and Specifications UHF Radio Specifications GENERAL FCC Designations: AZ492FT4786 AZ492FT4787 Temperature Range: Operating: Storage: Power Supply: RECEIVER –30°C to +60°C –40°C to +85°C Frequency Range: Range 1: Range 2: Range 3: Range 4: TRANSMITTER 403–433 MHz 438–470 MHz 450–482 MHz 482–512 MHz Channel Spacing: 12.
Model Numbering, Charts, and Specifications xxxvii 800 MHz Radio Specifications GENERAL FCC Designations: RECEIVER AZ492FT5759 AZ492FT5751 Frequency Range: TRANSMITTER 851–869 MHz Frequency Range: Repeater Mode: Talk-Around Mode: 806–824 MHz 851–869 MHz Channel Spacing: 12.5 kHz/20 kHz/25 kHz Input Impedance: 50 Ohm Rated Output Power: Mid-Power Radio: 15 Watt Frequency Separation: 18 MHz High-Power Radio: 35 Watt Sensitivity: (per EIA spec.
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Chapter 1 Introduction 1.1 General This manual includes all the information necessary to maintain peak product performance and maximum working time. This detailed level of service (component-level) is typical of some service centers, self-maintained customers, and distributors. Use this manual in conjunction with the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (Motorola part number 68P81076C20), which helps in troubleshooting a problem to a particular board.
1-2 1.2 Introduction: Notations Used in This Manual Notations Used in This Manual Throughout the text in this publication, you will notice the use of warnings, cautions, and notes. These notations are used to emphasize that safety hazards exist, and care must be taken and observed. NOTE: An operational procedure, practice, or condition that is essential to emphasize. ! CAUTION indicates a potentially hazardous situation which, if not avoided, may result in equipment damage.
Chapter 2 General Overview 2.1 Introduction The ASTRO Digital Spectra radio is a dual-mode (trunked/conventional), microcontroller-based transceiver incorporating a Digital Signal Processor (DSP). The microcontroller handles the general radio control, monitors status, and processes commands input from the keypad or other user controls. The DSP processes the typical analog signals and generates the standard signaling digitally to provide compatibility with existing analog systems.
2-2 2.2 General Overview: Analog Mode of Operation Analog Mode of Operation When the radio is receiving, the signal comes from the antenna/antenna-switch on the power amplifier board to the front-end receiver assembly. The signal is then filtered, amplified, and mixed with the first local-oscillator signal generated by the voltage-controlled oscillator (VCO). The resulting intermediate frequency (IF) signal is fed to the IF circuitry on the RF board, where it is again filtered and amplified.
General Overview: Control Head Assembly 2.4.3 2-3 Display (W9 Model) The control-head assembly for a W9 model has an 11-character, alphanumeric, vacuum fluorescent display. It needs three separate voltages to operate; the cathode needs 35 V to accelerate electrons to the anode; the grid needs 40 V to totally shut off current flow; the filament needs 3.8 Vac at 80mA. These voltages are obtained from the transformer on the display controller board. 2.4.
2-4 2.4.9 General Overview: Control Head Assembly Vehicle Interface Ports The Vehicle Interface Ports (VIPs) allow the control head to activate external circuits and receive inputs from the outside world. In general, VIP outputs are used for relay control and VIP inputs accept inputs from external switches. See the cable kit section for typical connections of VIP input switches and VIP output relays.
General Overview: Power Amplifier 2.5 2-5 Power Amplifier The power amplifier (PA) is a multi-stage, discrete-transistor RF amplifier consisting of the following: • Low-level power controlling stage • Drivers • Final amplifier • Directional coupler • Antenna switch • Harmonic filter 2.5.1 Gain Stages The first stage buffers the RF signal, filters harmonics, and acts as a variable amplifier.
2-6 2.6 General Overview: Front-End Receiver Assembly Front-End Receiver Assembly The receiver front-end consists of a preselector, a mixer circuit, and an injection filter. The receiver injection (1st local oscillator) comes from the VCO assembly through a coax cable. The injection filter is either fixed-tuned or tuned at the factory depending upon the bandsplit. The output of the filter is connected to the mixer. The preselector is a fixed-tuned filter.
General Overview: Command Board 2-7 The VCO output is coupled to a transistor for amplification and for impedance buffering. The output of this stage passes through a low-pass filter where the signal is split into three paths. One path feeds back to the synthesizer prescaler; the other two provide injection for the RX and TX amplification strings. The receive injection signal is further amplified and passed to the RX front-end injection filter.
2-8 General Overview: Radio Power The support-logic IC acts as an extension of the microcontrol unit by providing logic functions such as lower address latch, reset, memory address decoding, and additional control lines for the radio. The VOCON board controls a crystal-pull circuit to adjust the crystal oscillator frequency on the microcontrol unit, so that the E-clock harmonics do not cause interference with the receive channel.
General Overview: Radio Power 2-9 When the command board regulators are “on,” the 9.6-V output sources the command board and RF board circuits. The switched +5 V is routed to the VOCON board. See Figure 2-1. Control Head RF Power Amp Command Board A+ 9.6V UNSW +5V SW +5V SW 9.4V Keyed 9.4V 9.6V VOCON Board Battery 12V P1 SWB+ On/Off 5W A+ Synth 9.6V J2-5 A+ RF Board IGN 9.6V RF Filter Figure 2-1. DC Voltage Routing Block Diagram The 9.
2-10 General Overview: Radio Power Transistor Q206 controls solid-state power switch Q207, providing SWB+ to the encryption module (if equipped). The "SWB+" and "UNSWB+" encryption voltages both originate from pin 38 of J501 and are fed to the encryption module via J801. Port PL3 (5-V EN) on the SLIC and Q207 are under the control of the microcontroller unit (MCU), U204. This allows the MCU to follow an orderly power-down sequence when it senses that the B+ sense is off.
Chapter 3 Theory of Operation 3.1 RF Board This section provides a detailed circuit description of the ASTRO RF board for VHF, UHF and 800 MHz models. This board contains the common synthesizer circuits (synthesizer section) and dual IF receiver and demodulation circuits (receiver back-end). When reading the theory of operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”.
3-2 Theory of Operation: RF Board 6 5 4 3 2 NC 7 8 9 10 11 12 13 14 15 16 PNP BASE 5V OUT 42 43 PRE BC1 VREF 41 BC2 40 MOD PRE CONT OUT VCC MULTI - MODULUS PRESCALER BS AUX 5V REG 5V REG GND 44 PRE IN AUX AUX 5V PNP BASE OUT B+ IN LATCH u P S.F. VIN U601 MOSAIC PRESCALER S U P E R S.F. BASE 2ND L.O. CHARGE - PUMP PHASE DETECTOR S.F. OUT F I L T E R S.F. CAP 2ND L.O. CE I N T E R F A C E 300KHz GND DATA CLOCK 0 DET REF IN NC 0 DET OUT DATA OUT 8 2ND L.O.
Theory of Operation: RF Board 3-3 The reference oscillator generates the 16.8 MHz signal that serves as the reference for all radio frequency accuracy. It uses a proprietary temperature compensation circuit to keep the radio within its specified frequency tolerance. The receiver back-end uses the ABACUS II IC (U301) to demodulate all the way to baseband, starting from the first IF. 3.1.2 Synthesizer This section discusses the synthesizer components and detailed theory of operation. 3.1.2.
3-4 Theory of Operation: RF Board The synthesizer generates a modulus control output which instructs the prescaler to divide by either P or P + 1 (that is, 255 or 256). When modulus control is low, the prescaler is dividing by P + l (256) and the A counter is running; when modulus control is high, the prescaler is dividing by P (255) and the B counter is running. One complete cycle of loop division is repeated for each reference period.
Theory of Operation: RF Board 3-5 3.1.2.4 Phase Modulator ASTRO radios use a dual-port modulation scheme. The nature of the synthesizer loop is to track out low-frequency errors. In order to enable low-frequency modulation, such as DPL, the reference signal is modulated with the same signal as the VCO. Effectively, this prevents the low-frequency error in the loop (DPL) from tracking out because the same error is on the reference signal.
3-6 Theory of Operation: RF Board 3.1.2.7 Second VCO The second VCO is a grounded-gate, FET Colpitts oscillator. The resonator consists of a fixed inductor and a varactor. A potentiometer, R634, adjusts the negative voltage to the varactor. This adjustment is performed at board test to bring the phase detector output to the center of its linear region; that is approximately 2.25 V.
Theory of Operation: RF Board 3-7 3.1.3.2 ABACUS II IC Once in the ABACUS II IC (U301), the first IF frequency is amplified and then down converted to 450 kHz, the second IF frequency. At this point, the analog signal is converted into two digital bit streams by a sigma-delta A/D converter. The bit streams are then digitally filtered and mixed down to baseband and filtered again. The differential output data stream is then sent to the VOCON board where it is decoded to produce the recovered audio.
3-8 3.2 Theory of Operation: Command Board Command Board This section of the theory of operation provides a detailed circuit description of the ASTRO Digital Spectra Command Board. When reading the Theory of Operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component.
Theory of Operation: Command Board 3.2.3 3-9 Power-Up/-Down Sequence Normally, switched B+ (SWB+) enters the command board from P502, pin 31. This voltage is derived from the battery A+ voltage which enters the control head through P502, pin 30. A power FET transistor, located in the control head (W5 and W7 models), provides the means of controlling the main power source via the control head’s on/off switch.
3-10 3.2.4 Theory of Operation: Command Board Regulators The regulator circuits include an unswitched +5 V (UNSW5V) discrete circuit, and the regulator/ power-control IC (RPCIC) that produces switched +5 V (U500, pin 14) and 9.6 V (U500, pin 17). The UNSW+5-V source is used by the RPCIC as a reference (U500, pin 20) for its switched + 5-V source. This regulated voltage is produced from the A+ voltage and is present when the battery is connected.
Theory of Operation: Command Board 3-11 The three inputs to the NOR gate (SW9.6-V, RPCIC EN, and RPCIC_EN delayed) must be at a logic low to enable the power-on reset (POR*) to a high logic state. During this power-up sequence, this reset is delayed approximately 170 ms after the B+ voltage is sensed. This delay is needed to allow the supply voltages and oscillators to stabilize before releasing the VOCON board’s microprocessor.
3-12 3.2.7 Theory of Operation: Command Board Synchronous Serial Bus (MOSI) The synchronous serial bus is an internal bus used by the microcontroller for communicating with various ICs. The serial bus, called MOSI (master out/ slave in), is used to program the digital-toanalog (D/A) converter IC (U526), the serial-to-parallel shift register (U530) on the command board, and the ABACUS II IC (U301) on the RF board.
Theory of Operation: Command Board 3-13 3.2.10 Transmit Deviation The analog transmit deviation (MAI) enters the VOCON board through P501, pin 39, and is converted to a digital format. The digital representation is processed and pre-emphasized by the DSP processor. The pre-emphasized digital bit stream is converted back to analog by the ADSIC device. The modulation enters the command board through P501, pin 49 (MOD IN) and P501, pin 48 (REF MOD).
3-14 Theory of Operation: Command Board 3.2.14 Regulator and Power-Control IC The regulator and power-control IC (RPCIC), U500, contains internal circuitry for the 9.6-V regulator and the switched +5-V regulator. Refer to Section 3.2.4, "Regulators," on page 3-10 for detailed theory of operation. The power-control section of the device is responsible for maintaining a constant RF output power.
Theory of Operation: ASTRO Spectra VOCON Board 3.3 3-15 ASTRO Spectra VOCON Board This section of the theory of operation provides a detailed circuit description of an ASTRO Digital Spectra Vocoder/Controller (VOCON) Board. When reading the Theory of Operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component.
3-16 Theory of Operation: ASTRO Spectra VOCON Board The SLIC (U206) performs many functions as a companion IC for the MCU. Among these are expanded input/output (I/O), memory decoding and management, and interrupt control. It also contains the universal asynchronous receiver transmitter (UART) used for the RS232 data communications. The SLIC control registers are mapped into the MCU (U204) memory space.
Theory of Operation: ASTRO Spectra VOCON Board 3.3.3 3-17 Vocoder Section Refer to Figure 3-8 and your specific schematic diagram. The vocoder section of the VOCON board is made up of a digital signal processor (DSP) (U405), 24k x24 static-RAM (SRAM) (U414, U403, and U402), 256kB FLASH ROM (U404), and ABACUS II/DSP support IC (ADSIC) (U406). The FLASH ROM (U404) contains the program code executed by the DSP.
3-18 Theory of Operation: ASTRO Spectra VOCON Board When transmitting, the microphone audio is passed from the command board to the ADSIC, which incorporates an analog-to-digital (A/D) converter to translate the analog waveform to a series of data. The data is available to the DSP through the ADSIC parallel registers. In the converse way, the DSP writes speaker data samples to a D/A in the ADSIC, which provides an analog speaker audio signal to the audio power amplifier on the command board.
Theory of Operation: ASTRO Spectra VOCON Board IRQB 8KHz 3-19 IRQB D8-D23 DSP56001 U405 SC0 SC1 SSI SERIAL SC2 SCK SRD STD SDO ADSIC U406 A0-A2,A13-A15,RD*,WR* 2.4 MHz Receive Data Clock 20 KHz RX Data Interrupt 48KHz TX Data Interrupt 1.2 MHz Tx Data Serial Clock Serial Receive Data Serial Transmit Data Command Board Interface J501-40 ABACUS II Interface SCKR RFS TFS SBI DIN SCKT RXD TXD DINIDC SBI J501-6 Data In Data In* ODC J501-2 J501-1 J501-7 MAEPF-25107-O Figure 3-9.
3-20 Theory of Operation: ASTRO Spectra VOCON Board The DSP accesses this data through its SSI port. This is a 6 port synchronous serial bus. It is used by the DSP for both transmit and receive data transferal, but only the receive functions will be discussed here. The ADSIC transfers the data to the DSP on the SRD line at a rate of 2.4 MHz. This is clocked synchronously by the ADSIC which provides a 2.4 MHz clock on SC0.
Theory of Operation: ASTRO Spectra VOCON Board 3.3.5 3-21 TX Signal Path The transmit signal path follows some of the same design structure as the receive signal path described in Section 3.3.4, "RX Signal Path," on page 3-18 (refer to Figure 3-10). It is advisable to read through the section on RX Signal Path that precedes this section. IRQB 8KHz IRQB D8-D23 DSP56001 U405 SC0 SC1 SSI SERIAL SC2 SCK SRD STD VVO ADSIC U406 A0-A2,A13-A15,RD*,WR* 2.
3-22 Theory of Operation: ASTRO Spectra VOCON Board These samples are then input to a transmit D/A, which converts the data to an analog waveform. This waveform is the modulation out signal from the ADSIC ports, VVO and VRO. These signals are both sent to the command board, where they go through a gain stage and then to the VCO and Synthesizer. VVO is used primarily for audio frequency modulation; VRO is used to compensate for low-frequency response to pass Digital Private Line (DPL) modulated signals.
Theory of Operation: ASTRO Spectra VOCON Board 3-23 The same UART internal to the MCU is used in the controller bootstrap mode of operation. This mode is used primarily in downloading new program code to the FLASH ROMs on the VOCON board. In this mode, the MCU accepts special code downloaded at 7200 baud through the SCI bus instead of operating from program code resident in its ROMs.
3-24 3.3.7 Theory of Operation: ASTRO Spectra VOCON Board Vocoder Bootstrap The DSP has two modes of bootstrap: from program code stored in the FLASH ROM U404, or retrieving code from the host port. During normal modes of operation, the DSP executes program code stored in the FLASH ROM, U404. Unlike the MCU, however, the DSP moves the code from the FLASH ROM into the three SRAMs, U402, U403, and U414, where it is executed from.
Theory of Operation: ASTRO Spectra VOCON Board 3-25 MAP 2 $0000 NON-MUX 32K COMMON $0000 External RAM $1000 $2000 Int EE F1 REGS $1060 $3000 $4000 $5000 * F1 INT RAM SLIC REG HOST PORT * $6000 $0E00 $1000 Ext RAM $1400 $1500 $1600 $1800 $7000 $8000 External RAM $9000 $A000 $B000 $C000 $3fff $D000 $E000 $F000 $FFFF SLIC III REGISTER $1400 - $14FF F1 REGISTERS AND MEMORY: * * COMMON ROM RAM BANKED ROM/EEPROM CONTROLLED BY SLIC EXTERNAL EEPROM CONTROLLED BY F1 INT RAM: $
3-26 Theory of Operation: ASTRO Spectra VOCON Board The MCU executes program code stored in the FLASH ROMs. On a power-up reset, it fetches a vector from $FFFE, $FFFF in the ROMs and begins to execute code stored at this location. The external SRAM along with the internal 1Kx8 SRAM is used for temporary variable storage and stack space. The internal 512 bytes of EEPROM along with the external EEPROM are used for non volatile storage of customer-specific information.
Theory of Operation: ASTRO Spectra VOCON Board P Dx 3-27 Dy $FFFF ADSIC Registers $E000 $DFFF ADS Vectors External ROM 16KB Physical Banks $00000-1FFFF External ROM 16KB Physical Banks $20000-3FFFF $A000 $9FFF Not Used $8000 $7FFF External RAM External RAM External RAM U401 U402 U403 ADS P Ram Internal P Ram ADS Dx Ram Internal X Rom Internal Dx Ram ADS Dy Ram Internal Y Rom Internal Dy Ram $2000 $1FFF $1000 $0FFF $0200 $01FF $0000 MAEPF-26007-A Figure 3-13.
3-28 Theory of Operation: ASTRO Spectra VOCON Board The DSP program code is stored in the FLASH ROM, U404. During normal modes of operation, the DSP moves the appropriate program code into the three SRAMs (U401, U402, and U403) and internal RAM for execution. The DSP never executes program code from the FLASH ROM itself. At power-up after reset, the DSP downloads 512 words (1536 bytes) from the ROM, starting at $C000, and puts it into the internal RAM, starting at $0000, where it is executed.
Theory of Operation: ASTRO Spectra VOCON Board 3-29 During this process, the MCU does power diagnostics. These diagnostics include verifying the MCU system RAM, and verifying the data stored in the internal EEPROM, external EEPROM, and FLASH ROMs. The MCU queries the DSP for proper status and the results of DSP self tests. The DSP self tests include testing the system RAM, verifying the program code in ROM U404, and returning the ADSIC configuration register checksum.
3-30 Theory of Operation: ASTRO Spectra VOCON Board Table 3-3.
Theory of Operation: ASTRO Spectra VOCON Board 3-31 Table 3-4.
3-32 Theory of Operation: ASTRO Spectra VOCON Board Table 3-6. U204 (MCU) U204 Pin # July 1, 2002 Description To/From B1 PE0 R260 B2 PE1 B SENSE/LBAT/PWR DWN VR214 C3 PE2 N/C A3 PE3 EMERG J901-4 D3 PE4 N/C A2 PE5 N/C B3 PE6 SPKR COMMON R263 C4 PE7 EXT SPKR R261 B7 4XECLK (7.
Theory of Operation: ASTRO Spectra VOCON Board 3-33 Table 3-6. U204 (MCU) (Continued) U204 Pin # Description To/From G7 PG4 ADSIC RST* U406-A8 F7 PG3 ADSIC SEL* U406-B8 H8 PG2 DSP RST* U405-G9 F6 PG1 ROSC/PSC CE* J501-12 H7 PG0 SYN SEL* J501-11 B6 R/W* U405-D9 U206-B3 A5 ECLK (1.8432 MHz) U206-A4 E8 XIRQ* R233 E7 IRQ* U206-E2 A6 EXTAL 7.3728 MHz Y201 A7 XTAL Q205C Table 3-7.
3-34 Theory of Operation: ASTRO Spectra VOCON Board Table 3-7.
Theory of Operation: ASTRO Spectra VOCON Board 3-35 Table 3-7. U206 (SLIC) (Continued) U206 Pin # Description To/From G7 MICEN J501-45 J9 B+ CNTL U409-2 Q206B E7 VIP OUT1 J501-22 K7 CS3B EMC MAKEUP* J801-12 G6 CS2B RAM SEL* U211-2 J7 CS1B HEN* U405-E8 G8 DISP EN*/LATCH SEL* J601-4 H9 RED LED N/C E8 GRN LED N/C E2 IRQ* U204-E7 Table 3-8.
3-36 Theory of Operation: ASTRO Spectra VOCON Board Table 3-8. VOCON U405 (DSP) (Continued) U405 Pin # Description To/From B5 SC1 U406-J4 B9 SC0 U406-K4 C6 SCLK U204-G3 U406-C9 A7 TXD/EMC RXD J801-3 B7 RXD/EMC TXD J801-4 G9 RESET/DSP RST* U204-H8 E10 HACK* R409 B19 HREQ* U204-H3 E8 HEN* U206-J7 D9 HR/W* U204-B6 Table 3-9.
Theory of Operation: ASTRO Spectra VOCON Board 3-37 Table 3-9. VOCON U406 (ADSIC) (Continued) U406 Pin # 68P81076C25-C Description To/From F2 SSW/EPS* U404-30 C9 SCLK/SPI SCK U204-G5 J501-8 J801-9 C10 SPO/MOSI J501-9 J801-8 C1 MA1 U501-39 B5 SDO U501-40 B1 VRO REFMOD J501-48 B2 MODIN J501-49 L3 RXD SRO 2.4 MHz U405-C5 J4 RFS SC1 U405-B5 K4 SCKR SCO U405-B9 H1 TXD STO U405-A2 H2 TFS SC2 48 kHz U405-B2 G3 SCKT SCK 1.
3-38 3.4 Theory of Operation: ASTRO Spectra Plus VOCON Board ASTRO Spectra Plus VOCON Board This section of the theory of operation provides a detailed circuit description of an ASTRO Digital Spectra Plus Vocoder/Controller (VOCON) Board. When reading the Theory of Operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists” of this manual.
Theory of Operation: ASTRO Spectra Plus VOCON Board 3-39 In addition to the SPI bus, the controller also maintains two asynchronous serial busses; the SB9600 bus and an RS232 serial bus. The SB9600 bus is for interfacing the controller section to different hardware option boards, some of which may be external to the radio. The RS232 is used as a common data interface for external devices. User input from the control head is sent to the controller through SB9600 bus messages.
3-40 Theory of Operation: ASTRO Spectra Plus VOCON Board When transmitting, the microphone audio is passed from the command board to the MC145483 CODEC (U402), which incorporates an analog-to-digital (A/D) converter to translate the analog waveform to a data stream. The data is made available to the DSP through the Serial Audio Port (SAP) of the Patriot IC. In the converse way, the DSP writes speaker data samples to a D/A in the CODEC (U402) through the SAP.
Theory of Operation: ASTRO Spectra Plus VOCON Board 3.4.4 3-41 ASTRO Spectra Plus RX Signal Path The vocoder processes all received signals digitally. This requires a unique back end from a standard analog radio. This unique functionality is provided by the ABACUS IC with the KRSIC (U200) acting as the interface to the DSP. The ABACUS IC located on the transceiver board provides a digital back-end for the receiver section.
3-42 Theory of Operation: ASTRO Spectra Plus VOCON Board The DSP accesses this data through its SSI port. The SSI port is used by the DSP for both transmit and receive data transferal, but only the receive functions will be discussed in this section. The KRSIC transfers the data to the DSP on the SRDB line at a rate of 1.2 MHz. This is clocked synchronously by the KRSIC which provides a 1.2 MHz clock on SC0B. In addition, a 20 kHz interrupt is provided on SC1B, signaling the arrival of a data packet.
Theory of Operation: ASTRO Spectra Plus VOCON Board 3-43 The analog microphone signal from the command board is passed to the ASTRO Spectra Plus VOCON on MAI (Mic Audio In). This signal passes through gain and attenuation stages so that the correct amplitude level of the audio is presented to the CODEC input. The CODEC contains a microphone A/D. The microphone A/D converts the analog signal to a digital data stream and transmits them to the SAP of the Patriot IC.
3-44 Theory of Operation: ASTRO Spectra Plus VOCON Board The ASTRO Digital Spectra Plus radio has an additional asynchronous serial bus, which utilizes the RS232 bus protocol. This bus utilizes the secondary UART in the Patriot IC (U300). It consists of TX / RS232 (J501-43), RX / RS232 (J501-50), CTS / RS232 (J501-5), and RTS / RS232 (J501-42). It is a four-wire duplex bus used to connect to external data devices.
Theory of Operation: ASTRO Spectra Plus VOCON Board 3.4.9 3-45 ASTRO Spectra Plus Voltage Regulators The ASTRO Spectra Plus VOCON board contains two voltage regulators, a 3-V regulator (U411) and a 1.8-V regulator (U410). SW+5-V, which is routed to the ASTRO Spectra Plus VOCON board from the command board, drives the two regulators. Figure 3-19 shows the DC distribution for the ASTRO Spectra Plus VOCON Board. ON Semiconductor LP2951 ON Semiconductor LP2951 V = 1.
3-46 Theory of Operation: ASTRO Spectra Plus VOCON Board 3.4.10 ASTRO Spectra Plus Radio Power-Up/Power-Down Sequence The radio power-up sequence begins when the user actuates the control head's on/off switch. The control head then produces the switched B+ (SWB+) output voltage which is routed to the command board. Upon sensing the SWB+ voltage, the command board circuitry powers on the 9.6V and the SW +5-V regulated supplies.
Theory of Operation: Voltage Control Oscillator 3.5 3-47 Voltage Control Oscillator This section of the theory of operation provides a detailed circuit description of voltage control oscillator (VCO). When reading the Theory of Operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component.
3-48 Theory of Operation: Voltage Control Oscillator The VCO output is coupled through C672 to Q645 to amplify the signal and provide load isolation for the VCO. The collector voltage of Q645 is normally about 5 Vdc. 3.5.1.4 Synthesizer Feedback The synthesizer locks the VCO on frequency by the VCO feedback to the prescaler IC on the RF board. The output of the VCO goes into a low-pass filter consisting of C685, L676, and C687.
Theory of Operation: Voltage Control Oscillator 3-49 3.5.2.2 Super Filter 8.6 V Super-filtered 8.6 V enters the carrier board at J601-12, through an R-C filter, then on to the drain of Q9610 and the collector of Q9635. 3.5.2.3 VCO The oscillator consists of Q9610, the main transmission line (T-line), varactor bank (CR9616-9617, C9616-9617, L9616) and feedback capacitors (C9611-9613). Components CR9610, C9614, and R9613 form an AGC circuit to prevent breakdown of the FET.
3-50 Theory of Operation: Voltage Control Oscillator 3.5.2.9 Doubler The first buffer output is coupled to the input of the doubler by C5663. Q5660 doubles the drive frequency and increases power by approximately 3 dB as a result of the high and low impedances presented to its collector at the doubled frequency and drive frequency, respectively. The collector impedances are presented by an elliptical high-pass filter (C5670-C5674, L5670, and L5671).
Theory of Operation: Voltage Control Oscillator 3-51 The positive steering line connects to the cathodes of the four varactors and the negative steering line connects to the anodes. The negative line should be -4.0 ±0.3 V and the positive line can go as high as 9 V, allowing a difference of 15 to 16 V between the two. Normally, at room temperature, the positive steering line will be between 1.5 and 5.5 V and will fluctuate with temperature change in the radio.
3-52 Theory of Operation: Voltage Control Oscillator Doubler-biasing differs between receive mode and transmit mode. For receive, R9677, R9678, and R9676 (in parallel to dissipate power) plus R9679 and R9680 bias the base of Q9675 to 0.7-V potential, if NO input RF power is applied to the base. For transmit mode, keyed 9.4 V is fed through CR9694 and another parallel resistor network R9674 and R9675. This raises the current to the collector of Q9675 via L9678, producing more power out. 3.5.3.
Theory of Operation: Receiver Front-End 3.6 3-53 Receiver Front-End This section of the theory of operation provides a detailed circuit description of receiver front-end (RXFE). When reading the Theory of Operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component.
3-54 Theory of Operation: Receiver Front-End 3.6.2.2 Theory of Operation The factory-tuned ceramic preselector filter accommodates RF input frequencies ranging from 438 to 470 MHz (Range 2), 450 to 482 MHz (Range 3), or 482 to 512 MHz (Range 4). The injection filter is tuned to pass frequencies from 549 to 580 MHz for Range 2, 559 to 592 MHz for Range 3, or 592 to 622 MHz for Range 4.
Theory of Operation: Power Amplifiers 3.7 3-55 Power Amplifiers This section of the theory of operation provides a detailed circuit description of the power amolifiers. When reading the Theory of Operation, refer to your appropriate schematic and component location diagrams located in “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component.
3-56 Theory of Operation: Power Amplifiers The final stage output network serves the dual purpose of impedance matching and power combining of the two final devices. R3872 and R3873 help balance the load impedances presented to the collectors of the final devices. Filtered A+ is routed to the final amplifier devices via the current sense resistor R3841, the ferrite bead L3881, and the coil L3880. The final stage output network terminates at C3889, which is the input to the antenna switch.
Theory of Operation: Power Amplifiers 3-57 3.7.1.1.3 Power Control Circuitry Command Board Circuitry N.C. N.C. 25 24 23 22 21 N.C. 26 N.C. N.C. 27 20 18 19 PACKAGE GROUND 29 17 30 31 A+ N.C. N.C. 28 9.
3-58 Theory of Operation: Power Amplifiers Control Voltage Limiter R3807 and R3808 form a voltage divider that connects to control voltage drive. The output of this voltage divider is connected to the control-voltage-limit input (pin 4) of the RPCIC. If the voltage at this input reaches 3.2 V, then the control voltage will be clamped to a maximum value. For the high-power VHF PA, this maximum value is 9 V. This voltage control limit is set by the values of R3807 and R3808.
Theory of Operation: Power Amplifiers 3-59 Temperature Sensing The temperature-sensing circuit of the PA works with the RPCIC to protect the PA devices from excessively high temperatures. On the PA board, this circuit (formed by resistors R3916, R3841, and thermistor RT3842), provides a temperature dependent voltage to the RPCIC via J1 pin 6. As the PA temperature increases, the resistance of RT3842 decreases, causing the voltage at pin 6 to increase.
3-60 Theory of Operation: Power Amplifiers Final Stage The final device is a 3- to 33-Watt device and is driven by the driver through a low-pass matching circuit that consists of C3815, C3816, C3817, L3811, C3819, C3821, C3822, C3823 and associated transmission lines. Base network, L3852, L3851, and R3815, R3819 provide the zero-DC bias required by the final device's Class-C operation. L3852 and L3851 provide the DC path from base to ground. R3815 and R3819 help lower the network's Q at low frequencies.
Theory of Operation: Power Amplifiers 3-61 N.C. N.C. 25 24 23 22 21 N.C. 26 N.C. N.C. 27 20 18 19 PACKAGE GROUND 29 17 30 31 A+ N.C. N.C. 28 9.6V DRIVE Q538 RPCIC ENABLE UNSW 5V REF The power control loop is controlled by the microprocessor U204 on the VOCON board. Through the SLIC IC U206, the microprocessor enables the RPCIC by pulling TX PA ENABLE (U500 pin 33) low while the radio synthesizer is locked (U500 pin 35).
3-62 Theory of Operation: Power Amplifiers The collector currents of the 25/10-Watt amplifier is monitored by sensing the voltage across R3875. CURRENT SENSE + connects to one end of R3875; CURRENT SENSE - connects to the other end. These lines connect to the command board on U500, Pins 37 and 38, respectively. If the TX CURRENT LIMIT is set for 1.5 V, then the voltage difference between U500, Pins 37 and 38 must be 0. 1 V before the current through R3875 is reduced. If U500, pin 40 is programmed for 4.
Theory of Operation: Power Amplifiers 3-63 3.7.1.3 50-Watt Power Amplifiers 3.7.1.3.1 Transmitter The 50-Watt ASTRO Spectra power amplifiers (PA's) are discussed in the following text. A block diagram of the circuit is shown in Figure 3-22. CONTROLLED TX BUFFER TX INJECTION E3850 PREDRIVER FINAL AMPLIFIER DRIVER DIRECTIONAL COUPLER P.I.N. SWITCH 10 mW Q3801 82D50 100 mW Q3804 M9859 1W Q3850 25C28 12 W Q3875 11L04 65 W 55 W MALE SMB/ TAIKO DENKI CONTROL VOLTS K9.4 9.
3-64 Theory of Operation: Power Amplifiers Final Stage The final device is a 12- to 75-Watt device and is driven by the driver through a low pass matching circuit that consists of C3850 through C3854 and associated transmission lines. Base network, L3852, L3853, and R3851, provide the zero-DC bias required by the final device's Class C operation. L3852 and L3851 provide the DC path from base to ground. R3851 helps lower the network's Q at low frequencies.
Theory of Operation: Power Amplifiers 3-65 3.7.1.3.3 Power Control Circuitry Command Board Circuitry N.C. N.C. 25 24 23 22 21 N.C. 26 N.C. N.C. 27 20 18 19 PACKAGE GROUND 29 17 30 31 A+ N.C. N.C. 28 9.6V DRIVE Q538 RPCIC ENABLE UNSW 5V REF Inside U500, the Regulator Power Control IC (Figure 3-23), is an operational amplifier that has four inverting inputs, and non-inverting input at pin 44 which is the reference input for the entire power control loop of the power amplifier.
3-66 Theory of Operation: Power Amplifiers Control Voltage Limiter R3807 and R3808 form a voltage divider that connects to control voltage drive. The output of this voltage divider is connected to the control-voltage-limit input, pin 4 of the RPCIC. If the voltage at this input reaches 3.2 V, then the control voltage will be clamped to a maximum value. For the 50-Watt VHF PA, this maximum value is 8 V. This voltage control limit is set by the values of R3807 and R3808.
Theory of Operation: Power Amplifiers 3-67 Temperature Sensing The temperature-sensing circuit of the PA works with the RPCIC to protect the PA devices from exclusively high temperatures. On the PA board, this circuit, formed by resistors R3878 thru R3880 and thermistor RT3877, provides a temperature-dependent voltage to the RPCIC via P0853, pin 7. As the PA temperature increases, the resistance of RT3875 decreases, causing the voltage at pin 7 to increase.
3-68 Theory of Operation: Power Amplifiers 3.7.2 UHF Band Power Amplifiers 3.7.2.1 High-Power Amplifier 3.7.2.1.1 Transmitter The high-power Spectra amplifier is discussed in the following text. A block diagram of the circuit is shown in. FINAL AMPLIFIER Q5875 25C29 J5901 INJECTION LLA 30mW Q5801 82D50 CONTROL VOLTAGE 2ND STAGE 250mW Q5803 25C09 K9.4 3RD STAGE 2W 9.
Theory of Operation: Power Amplifiers 3-69 Final Stage The final amplifier stage is the parallel combination of two 25-Watt input to 75-Watt output RF transistors. The matching network from the collector of the driver device Q5851 to the bases of the final devices Q5875 and Q5876 utilizes transmission lines as part of a combination matching network and power splitter. The capacitors C5885, C5886, C5887, and C5888 are on the bottom side of the PC board underneath the base leads of Q5875 and Q5876.
3-70 Theory of Operation: Power Amplifiers N.C. N.C. 25 24 23 22 21 N.C. 26 N.C. N.C. 27 20 18 19 PACKAGE GROUND 29 17 30 31 A+ N.C. N.C. 28 9.6V DRIVE Q538 RPCIC ENABLE UNSW 5V REF The power control loop is controlled by the microprocessor U204 on the VOCON board. Through the SLIC IC U206, the microprocessor enables the RPCIC by pulling TX PA ENABLE (U500 pin 33) low while the radio synthesizer is locked (U500 pin 35).
Theory of Operation: Power Amplifiers 3-71 The collector current of the high-power amplifier is monitored by sensing the voltage across R5875. CURRENT SENSE + connects to one end of R5875; CURRENT SENSE - connects to the other end. These lines connect to the command board on U500 pins 37 and 38, respectively. If the TX CURRENT LIMIT is set for 1.5 V, then the voltage difference between U500 pins 37 and 38 must be 0.1 V before the current through R5875 is reduced. If U500 pin 40 is programmed for 4.
3-72 Theory of Operation: Power Amplifiers 3.7.2.2 40-Watt Power Amplifier 3.7.2.2.1 Transmitter The 40-Watt ASTRO Spectra power amplifier is discussed in the following text. Transmit Low Level Amplifier (LLA) NOTE: The minimum input drive level to the PA into P5850 is 30 mW. Refer to the synthesizer section if input drive is less than 30 mW. The Low Level Amplifier, the first stage of the PA, provides a gain that is a function of a control voltage.
Theory of Operation: Power Amplifiers 3-73 3.7.2.2.2 Antenna Switch and Harmonic Filter Antenna Switch The antenna switch's impedance inverter circuit, made up of C5923 and L5921, takes the place of a quarter-wave microstrip line. During transmission, Keyed 9.4 V forward-biases CR5921, producing low impedance on CR5921's anode and high impedance on the C5923/L5921 node. Effectively, this isolates the transmitted power from the receiver, C5922 couples the power to the harmonic filter and on to the antenna.
3-74 Theory of Operation: Power Amplifiers 3.7.2.2.3 Power Control Circuitry Command Board Circuitry N.C. N.C. 25 24 23 22 21 N.C. 26 N.C. N.C. 27 20 18 19 PACKAGE GROUND 29 17 30 31 A+ N.C. N.C. 28 9.
Theory of Operation: Power Amplifiers 3-75 Control Voltage Limiter R5807 and R5808 form a voltage divider that connects to control voltage drive. The output of this voltage divider is connected to the control-voltage-limit input ( pin 4) of the RPCIC. If the voltage at this input reaches 3.2 V, then the control voltage will be clamped to a maximum value. For the 40-Watt UHF PA, this maximum value is 10 V. This voltage-control limit is set by the values of R5807 and R5808.
3-76 Theory of Operation: Power Amplifiers Temperature Sensing The temperature-sensing circuit of the PA works with the RPCIC to protect the PA devices from excessively high temperatures. On the PA board, this circuit, formed by resistors R5878, R5876, R5877, and thermistor RT5875, provides a temperature-dependent voltage to the RPCIC via P0853, pin 7. As the PA temperature increases, the resistance of RT5875 decreases, causing the voltage at pin 7 to increase.
Theory of Operation: Power Amplifiers 3.7.3 3-77 800 MHz Band Power Amplifiers 3.7.3.1 15- and 35-Watt Amplifiers 3.7.3.1.1 Transmitter The 15-Watt and 35-Watt ASTRO Spectra power amplifiers are discussed in the following text. Transmit Buffer The PA receives 18 to 23 dBm (60 to 200 mW) at the transmit injection (TX INJ) coax. The first stage, TX BUFFER, uses adaptive biasing which varies the base voltage inversely proportional to the input drive level. With Keyed 9.4 V (K9.
3-78 Theory of Operation: Power Amplifiers Final Stage (35-Watt Only) On the 15-Watt radio, the transmit RF signal from U9850, pin 5, is applied to the 50-ohm microstrip directional coupler. On the 35-Watt radio, the transmit RF signal is applied to the emitter of the final power amplifier Q9880 through the coupling capacitor C9856, the 50-ohm quarter-wave matching transmission line, and the matching capacitors C9875 and C9876.
Theory of Operation: Power Amplifiers 3-79 NOTE: When removing any of the discrete coils, take care to avoid leaching the plate capacitor metallization. Removal of the entire hybrid is best accomplished by heating hybrid/PC board assembly with a heat gun or heat blower until solder joint reflows. 3.7.3.1.
3-80 Theory of Operation: Power Amplifiers Power Module Control Voltage Limiter R9562 and R9563 connect in series to the emitter of Q9500. The ratio of R9563 and R9562 feed a portion of the control voltage (U9850, Pins 2 and 3) to U500, pin 4. When pin 4 exceeds 3.2 V, the output of the control op-amp (U500, pin 42) is reduced. Eventually, this reduces the control voltage available to the power module (U9850). The input RF power to the 45-Watt amplifier Q9880) must stay below 17 Watts.
Theory of Operation: Power Amplifiers 3-81 3.7.3.1.4 Temperature Sensing When the radio is keyed, K9.4-V is applied to pin 5 of the PA connector and on one side of thermistor RT9560. As the temperature increases, the resistance of RT9560 decreases, creating more voltage across R9561. This temperature voltage is routed via PA connector pin 7 back to U500, pin 13, which is the input to a thermistor buffer.
3-82 Theory of Operation: Power Amplifiers This Page Intentionally Left Blank July 1, 2002 68P81076C25-C
Chapter 4 Troubleshooting Procedures 4.1 ASTRO Spectra Procedures This section will aid you in troubleshooting a malfunctioning ASTRO Digital Spectra radio. It is intended to be detailed enough to localize the malfunctioning circuit and isolate the defective component. NOTE: Refer to “4.2 ASTRO Spectra Plus Procedures” on page 4-10 for troubleshooting information specific to the ASTRO Spectra Plus radio. ! Caution 4.1.1 Most of the ICs are static-sensitive devices.
4-2 4.1.2 Troubleshooting Procedures: ASTRO Spectra Procedures Voltage Measurement and Signal Tracing In most situations, the problem circuit may be identified using a dc voltmeter, RF millivoltmeter, and oscilloscope (preferably with 100 MHz bandwidth or more). The “Recommended Test Equipment, Service Aids, and Tools” section in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) outlines the recommended tools and service aids which would be useful.
Troubleshooting Procedures: ASTRO Spectra Procedures 4-3 Table 4-1. Power-Up Self-Check Error Codes (Continued) Error Code Description Troubleshooting Chart 01/92 Internal EEPROM checksum failure Chart C.10 (p. 9) 02/81 DSP ROM checksum failure Chart C.12 (p. 10) 02/82 DSP RAM 1 failure Chart C.15 (p. 12) 02/84 DSP RAM 2 failure Chart C.14 (p. 11) 02/88 DSP RAM failure - Note: Not a checksum failure Chart C.13 (p.
4-4 Troubleshooting Procedures: ASTRO Spectra Procedures - Set the EMC wake-up line high. 7. Begin power-up self-tests. 8. Begin RAM tests: - External RAM ($1800-3FFF). - Internal RAM ($1060-$1300). - External RAM ($0000-$0DFF). - Display 01/88 if failure. The radio will get stuck here if the internal RAM is defective. The radio uses the internal RAM for stack. The RAM routines use subroutines. Thus, if the internal RAM is defective, the radio will get lost testing the external RAM. 9.
Troubleshooting Procedures: ASTRO Spectra Procedures 4-5 12. Power-up the EMC (if it is enabled in the codeplug). 13. Turn off the green LED. 14. Start up operating system. 15. Display for one second: - “SELF TEST” for the W3, model. - “SELF CHK” for the W4, W5, and W7 models. - “SELF CHECK” for the W9 models. 16. Turn off the green LED in the W3 model, or the TX and Busy LEDs in the W4, W5, W7, and W9 models. Display errors if a fatal error exists at this time. 4.1.
4-6 Troubleshooting Procedures: ASTRO Spectra Procedures 4. Check the negative steering line, J601, pin 4. If correct, continue with the following checks. 5. Check the positive steering line, J601, pin 1 or 2 for positive voltage between 1.0 and 8.0 V. If not correct, go to “Incorrect Voltage at Positive Steering Line”; otherwise, continue with the following checks. NOTE: It is common for both steps 3 and 5 to be incorrect in an “out-of-lock” condition. 6. Check U602, pin 27 for a 1.
Troubleshooting Procedures: ASTRO Spectra Procedures 4-7 4.1.4.1.2 Incorrect Values at U602 Pin 25 (MODULUS CONTROL) If the frequency is not 6.25 kHz (or 5.0 kHz for VHF), verify the proper VCO pin-shift logic. See VCO block diagram (Figure 4-1) for pin-shift logic. Also, check the VCO feedback for approximately -10 to 5 dBm at proper VCO frequency. Use the following table: Table 4-3. Feedback Frequency Ranges Band VCO Feedback Frequency VHF TX Freq x 2 or RX Freq + 109.
4-8 Troubleshooting Procedures: ASTRO Spectra Procedures At 450 MHz, there are 72,000 counts of 2.22 nanoseconds each per reference period. When modulus control (MCT) is high, the VCO output is prescaled by 255 (see the diagram below). The output frequency of the prescaler is 1.765 MHz which corresponds to a period, per-cycle, of 567 nanoseconds. The “A” counter runs long enough to count down 90 cycles which equals 51 microseconds. When MCT is low, the prescaled output equals 1.
Troubleshooting Procedures: ASTRO Spectra Procedures 4.1.5 4-9 Standard Bias Table Table 4-4, below, outlines some standard supply voltages and system clocks which should be present under normal operation. These should be checked as a first step to any troubleshooting procedure. Table 4-4. Standard Operating Bias Signal Name Nominal Value Tolerance Source UNSW_B+ 13.8 Vdc 11.0-16.6 Vdc J501 SW_B+ 13.8 Vdc 11.0-16.6 Vdc J501 +5V 5.0 Vdc ±10% J501 +5VA 5.0 Vdc ±10% J501 RESET 5.
4-10 4.2 Troubleshooting Procedures: ASTRO Spectra Plus Procedures ASTRO Spectra Plus Procedures This section will aid you in troubleshooting a malfunctioning ASTRO Digital Spectra Plus radio. It is intended to be detailed enough to localize the malfunctioning circuit and isolate the defective component. ! Caution Most of the ICs are static-sensitive devices. Do not attempt to troubleshoot or disassemble a board without first referring to the following Handling Precautions section.
Troubleshooting Procedures: ASTRO Spectra Plus Procedures 4-11 Table 4-5.
4-12 4.2.3 Troubleshooting Procedures: ASTRO Spectra Plus Procedures Error Code 09/10 Cycle power to the radio. If this fails then follow instructions as per troubleshooting chart C.32 Error Code 09/90 Cycle power to the radio. If this fails then follow instructions as per troubleshooting chart C.32 ASTRO Spectra Plus Standard Bias Table Table 4-6 outlines some standard supply voltages and system clocks which should be present under normal operation.
Troubleshooting Procedures: VCO Procedures 4.3 4-13 VCO Procedures This section provides band-specific troubleshooting procedures for the VCO. 4.3.1 VHF Band Use these instructions along with the Theory of Operation, the block diagram, and the schematic to help isolate failures: first, to the individual circuits, and finally, to the failing piece part. 4.3.1.1 VCO Hybrid Assembly The VCO hybrid substrate is glued to the carrier board. The hybrid is not a field-repairable assembly.
4-14 Troubleshooting Procedures: VCO Procedures If the AUX 1* and AUX 2* voltages are correct and the synthesizer feedback level is correct but an out-of-lock condition persists, troubleshoot the synthesizer. AUX 1 J601-11 AUX 2 J601-9 SF 8.6 J601-12 9.6 J601-2 PIN DIODE DRIVERS BIAS BIAS RX INJECTION TO RECEIVER FRONT END > + 19dBm J601-3 +SL -SL J601-4 LOW PASS FILTER Q3645 VCO PAD Q3675 J3642 VCO SUBSTRATE J601-10 MOD K9.4 J601-5 SYNTHESIZER J601-1 FEEDBACK PAD BIAS _.. 2 U3676 K9.
Troubleshooting Procedures: VCO Procedures 4-15 Table 4-7. VCO Frequency Mode AUX 1 AUX 2 Radio Freq (MHz) VCO Freq (MHz) Port Freq (MHz) Port HIGH HIGH HIGH LOW LOW 136.00 - 158.35 158.35 - 162.00 136.00 - 145.20 145.20 - 157.00 157.00 - 162.00 245.65 - 268.00 268.00 - 271.65 272.00 - 290.40 290.40 - 314.00 314.00 - 324.00 245.65 - 268.00 268.00 - 271.65 136.00 - 145.20 145.20 - 157.00 157.00 - 162.00 (RX) (RX) (TX) (TX) (TX) HIGH HIGH HIGH LOW LOW 146.00 - 166.15 166.15 - 174.00 146.
4-16 Troubleshooting Procedures: VCO Procedures 4.3.2.2 Out-of-Lock Condition The probable cause of an out-of-lock condition is a failure in the synthesizer circuit. (See Section 4.1.4.2 Review of Synthesizer Fundamentals on page 4-7.) If the voltages on the AUX 1*, AUX 2*, or -8V lines at P0601 do not conform to the values shown in Figure 4-2, check the pin shift circuitry on the carrier board for proper operation. If no trouble is found, troubleshoot the synthesizer.
Troubleshooting Procedures: VCO Procedures 4-17 4.3.2.4 No or Low Modulation Under standard test conditions with a 1 kHz tone injected and 4.5 kHz deviation, there should be 700 mV (RMS) ±20% present on P0601-10. If this level is not present, troubleshoot the modulation circuit on the carrier board and then troubleshoot the audio circuitry. If the proper level is present, troubleshoot the modulation circuitry on the VCO kit. If no failure exists, replace the VCO.
4-18 4.3.3 Troubleshooting Procedures: VCO Procedures 800 MHz Band Use these instructions along with the Theory of Operation, the block diagram, and the schematic to help isolate failures, first, to the individual circuits, and finally to the failing piece part. 4.3.3.1 VCO Hybrid Assembly The VCO hybrid substrate is glued to the carrier board. The hybrid is not a field-repairable assembly. If a failure is indicated in this assembly, replace the entire carrier board. 4.3.3.
Troubleshooting Procedures: VCO Procedures 4-19 4.3.3.3 No or Low Output Power (TX or RX Injection) Use the test cables listed in the “Service Aids” in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). Measure the power at the synthesizer feedback port-if it is not within the range specified in the block diagram, troubleshoot the first buffer. If failure is found in the first buffer, replace the defective component.
4-20 4.4 Troubleshooting Procedures: Receiver Front-End (RXFE) Receiver Front-End (RXFE) This section provides band-specific troubleshooting procedures for the receiver front-end. 4.4.1 VHF Band This information will help you troubleshoot the Spectra radio. Use this information, along with the Theory of Operation, to diagnose and isolate the cause of failures. The principle tools needed to troubleshoot a circuit to the component level are the schematic and the Theory of Operation.
Troubleshooting Procedures: Power Amplifier Procedures 4.5 4-21 Power Amplifier Procedures This section provides band-specific troubleshooting procedures for the power amplifier. 4.5.1 VHF Band 4.5.1.1 High-Power Amplifier This information will help you troubleshoot the Spectra radio. Use this information, along with the Theory of Operation, to diagnose and isolate the cause of failures.
4-22 Troubleshooting Procedures: Power Amplifier Procedures Begin troubleshooting by connecting an RF power meter and appropriate power load to the antenna connector. Connect the control cable and the power cable. Make sure the ignition sense lead is also connected to the positive lead of the power supply. Note that a regulated DC power supply capable of at least 30 A. is necessary to power a high-powered Spectra transmitter. Remove the radio bottom cover.
Troubleshooting Procedures: Power Amplifier Procedures 4-23 If it is verified that both power set and current limit are not related to the power problem, then the synthesizer output must be checked. A milliwatt meter connected to the TX injection cable should indicate at least 10 mW of injection power during key-up. If this is not the case, refer to the RF board and VCO sections of this manual for troubleshooting procedures. Table 4-8.
4-24 Troubleshooting Procedures: Power Amplifier Procedures Table 4-8. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION LOW TYP HI LOW TYP HI 0 1.2 6.0 COMMENTS J1 13 0 14 5.0 5.0 Thermister Buffer in 5-V Sense Input (follows pin 20 ±0.1 V) 15 4.9 5.0 5.7 4.9 5.0 5.7 5-V Current Limit (limits at 5.7 V) 16 5.0 5.7 6.4 5.0 5.7 6.4 5-V Series Pass Drive (6.4 at max current) 17 9.5 9.6 9.9 9.5 9.6 9.9 9.6-V Sense Input 18 7 7 19 5.7 5.7 20 4.
Troubleshooting Procedures: Power Amplifier Procedures 4-25 Table 4-8. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION LOW TYP HI LOW TYP HI 0 0 0 0 0 0 9.6 COMMENTS J1 41 Ground 42 0 2.2 43 1.3 7.0 Loop Integrator Capacitor 44 2.1 3.2 Control AMP Reference Q0500E 13.0 13.0 A+ - CR0500 Drop Q0501C 12.3 12.3 VQ0500E - B/E Drop Q0501E 0.2 0.2 V pin 23 - B/E Drop Q0503E 0 1.5 V pin 42 - B/E Drop (TX) Q0503C 13.6 9.0 Q0504B 13.6 12.
4-26 Troubleshooting Procedures: Power Amplifier Procedures Testing Low-Level Amplifier (LLA) Circuitry Proper operation of the LLA can be checked by monitoring the voltage across resistor R3804. The voltage should measure in the range of 0.4 V to 1.0 V, depending on the value of control voltage. A 0.4-V reading corresponds to a low control voltage (4 to 5 V) and a 1.0-V reading corresponds to a high control voltage (up to control voltage limit). Measure LLA voltages according to Table 4-9.
Troubleshooting Procedures: Power Amplifier Procedures 4-27 Troubleshooting the Driver Stage (Q3805) • Make sure A+ is at the collector. • Check for shorts and/or opens in the matching circuitry. Also look for faulty components (cracked parts or parts not properly soldered). • Measure the DC resistance from base to emitter. It should be less than 1-ohm. If not, check L3812 and L3809 for proper soldering, and replace if faulty. • Check the current drain of Q3805.
4-28 Troubleshooting Procedures: Power Amplifier Procedures Additional antenna switch tests are: • Check CR3901, CR3902, and CR3903 using the diode check function of a multimeter. Note that CR3903 is on the bottom side of the board. This diode affects the receive path only and is unrelated to transmitter problems. • Check for proper DC current through the PIN diodes; correct current is indicated if approximately 1.5 V is present at the junction of R3900 and L3900 during transmit.
Troubleshooting Procedures: Power Amplifier Procedures 4-29 The directional coupler samples a small amount of forward power during transmit. This power is rectified by a detector diode CR3904. This rectified DC voltage is fed back to the RPCIC where it is compared to a reference voltage. An error voltage is generated which is ultimately translated into the control voltage via RPCIC circuitry and amplifiers Q503 and Q504 on the command board.
4-30 Troubleshooting Procedures: Power Amplifier Procedures After a PA board is replaced, or if any power control circuitry components are replaced, readjust the power according to instructions in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). NOTE: Due to high operating frequencies, you must use specified Motorola parts when component replacement is necessary. Substitute components may not work.
Troubleshooting Procedures: Power Amplifier Procedures 4-31 3. Apply the required input power via an adapter cable. For this application, non 'N' type connectors are acceptable. A+ TO COMMAND BOARD A+ TO COMMAND BOARD CURRENT SENSE + CURRENT SENSE CONTROL VOLTAGE LIMIT 2 1 4 3 8 6 5 7 10 9 12 11 FEMALE RECEPTACLE CONNECTOR W 100 MIL SPACING MATES TO P853 REGULATED 9.6V CONTROL VOLTAGE DRIVE V DETECT K9.4 TEMP SENSE Figure 4-5. PA Test Adapter, 25/10 Watt Power Amplifier 4.
4-32 Troubleshooting Procedures: Power Amplifier Procedures Table 4-11. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 10 10.8 13.8 16.6 10.4 13.4 16.2 11 9.4 9.6 9.9 9.4 9.6 9.9 12 10.8 9.8 13.1 15.9 A+ to Command Board 9.6-V Supply from Command Board Current Sense - (voltage delta 150 mV) U0500 1 0 2 3 0 0 0 0 0 4 0 5 0 6 0 1.5 0 0 3.2 0 Ground Control AMP Input 0 0 0 0 2 3.
Troubleshooting Procedures: Power Amplifier Procedures 4-33 Table 4-11. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 26 0 0 N.C. 27 13.6 13.6 N.C. 28 — — — — — — 9.6-V Programming (N.C.) 29 — — — — — — 9.6-V Programming (N.C.) 30 — — — — — — 9.6-V Programming (N.C.) 31 0 0 0 0 0 0 Ground 32 10.8 13.6 16.5 10.0 13.0 16.0 33 4.0 5.0 0 0.2 34 0 1.3 35 0 0 36 0 0.
4-34 Troubleshooting Procedures: Power Amplifier Procedures Table 4-12. Antenna Switch DC Voltage Chart TYPICAL RX TYPICAL TX NO PREDRIVE ANODE 0 1.6 CATHODE 0 0.8 ANODE 0 0.8 CATHODE — — ANODE 0 <0.8 CATHODE — — LOCATION CR3920 CR3921 CR3922 COMMENTS 4.5.1.2.3 Localizing Problems Failure locations often can be determined by externally measured symptoms. Basic symptoms are noted below with probable failure locations. 1.
Troubleshooting Procedures: Power Amplifier Procedures 4-35 4.5.1.2.4 Isolating Failures Methods of analyzing individual stages of the Power Amplifiers are detailed below. Most of the stages are Class C and must be analyzed under relatively high RF power levels. Generators capable of such levels may not be available in all service shops, therefore the tests below are arranged in order of ascending power. This tends to allow the preceding stage to be the source of RF power for testing the next stage.
4-36 Troubleshooting Procedures: Power Amplifier Procedures Testing Driver Circuitry The driver is a typical Class-C stage, except the base is biased with resistors R3809 and R3810. The necessary conditions for proper operation of this stage are input drive power, and bias conditions as shown in Table 4-13. NOTE: If it is necessary to replace Q3804, use a hot-air blower to remove and replace the part. It is important that the replacement device's case be properly soldered to its heatsink.
Troubleshooting Procedures: Power Amplifier Procedures 4-37 - Check for proper DC current through the PIN diodes; correct current is indicated if approximately 1.5 V is present at the junction of C3900 and L3900 during transmit mode. ! DO NOT measure bias directly at the PIN diodes while in transmit mode unless TX injection is removed. WARNING 4.5.1.2.
4-38 Troubleshooting Procedures: Power Amplifier Procedures Power-Leveling Circuitry Test With the radio connected for power measurements, vary the line voltage from 12.5 to 16 V. The power should not vary more than 2 Watts. At a line voltage of 13.8 V, vary the frequency using the three test modes. If power varies more than 2 Watts, measure the detected voltage on P0853, pin 9. If this voltage varies more than 0.
Troubleshooting Procedures: Power Amplifier Procedures 4-39 4.5.1.3.2 PA Functional Testing To test the PA assembly for proper operation, perform the following steps: 1. Disassemble the PA assembly from the radio, leaving the power cable connected to the rear connector. Replace the PA shield and cover. Disconnect the coax connectors and the ribbon cable. Connect a power meter to the antenna port using minimum cable length. a.
4-40 Troubleshooting Procedures: Power Amplifier Procedures 8. If no failure is located from the previous checks, troubleshoot the power control circuitry. A+ TO COMMAND BOARD A+ TO COMMAND BOARD CURRENT SENSE + CURRENT SENSE CONTROL VOLTAGE LIMIT 2 1 4 3 8 6 5 7 10 9 12 11 FEMALE RECEPTACLE CONNECTOR W 100 MIL SPACING MATES TO P853 REGULATED 9.6V CONTROL VOLTAGE DRIVE V DETECT K9.4 TEMP SENSE Figure 4-6. PA Test Adapter, 50 Watt Power Amplifier Table 4-15.
Troubleshooting Procedures: Power Amplifier Procedures 4-41 Table 4-15. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION 3 COMMENTS LOW TYP HI LOW TYP HI 0 0 0 0 0 0 0 2 3.2 4 0 5 0 6 1.5 0 Control AMP Input (not used) Control Voltage Limit (cutback at 3.3 V) N.C. 3.0 4.5 1.5 3.0 4.5 Power Set from D-A (max power at 1.5 V) 7 0 0 1.5 3.0 4.5 Power Set Buffer Out 8 0 1.3 3.5 6.0 Coupler Buffer Out 9 0 1.3 3.5 6.
4-42 Troubleshooting Procedures: Power Amplifier Procedures Table 4-15. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 32 10.8 13.6 16.5 10.0 13.0 16.0 33 4.0 5.0 0 0.2 34 0 1.3 35 0 0 36 0 0.8 Decoupled A+ TX PA Enable (from U520-25) Control AMP one-shot Lock (5-V of Synth Out of Lock) Control AMP one-shot 37 10.8 13.6 16.3 10.0 13.0 16.0 A+ (Current Sense +) 38 10.8 13.6 16.3 10.0 13.0 16.
Troubleshooting Procedures: Power Amplifier Procedures 4-43 3. Power Intermittently Low (or Zero) and Current Less than 1 A. When Power Drops - Check LLA stage. 4. Power Zero and Current Greater Than 5 A. - Check harmonic filter, antenna switch, and matching circuits beyond final stage. 5. Power Zero and Current Between 2 and 5 A. - Check driver and/or final stages. 6. Power Zero and Current Less Than 1 A. - Check LLA/driver circuitry. 4.5.1.3.
4-44 Troubleshooting Procedures: Power Amplifier Procedures If the above DC bias conditions are correct, check to see if the LLA is providing drive power to the pre-driver, Q3804. Do so by checking Q3804's collector current under normal drive conditions, as follows: • Remove R3810 and L3806 (Be sure to reinstall after testing). • Solder wires to the remaining pads. • Place an ammeter in series with the collector of Q3804. Check for 0.1 to 0.5 A. depending the control voltage.
Troubleshooting Procedures: Power Amplifier Procedures 4-45 • Unsolder either L3859, R3875, or L3851 to isolate the driver and final stages. Measure the collector emitter DC resistances. If the resistance is below 5k ohms, then replace the driver device. NOTE: The position of capacitors C3853 and C3854 is critical to the performance of the circuit. If they are removed for any reason, they must be re-installed as close to the cap of the final device as possible.
4-46 Troubleshooting Procedures: Power Amplifier Procedures Temperature Sense Circuit Test Temporarily place a leaded 6.8k ohm resistor in parallel with RT3875. Key the transmitter and monitor the output power. The power meter should read approximately 1/2 the rated power (25 Watts). Control-Voltage-Limit Circuitry Test Disconnect the transmitter injection from the internal transceiver chassis. This will require removal of the power amplifier assembly.
Troubleshooting Procedures: Power Amplifier Procedures 4.5.2 4-47 UHF Band 4.5.2.1 High-Power Amplifier This information will help you troubleshoot the Spectra radio. Use this information, along with the Theory of Operation, to diagnose and isolate the cause of failures. This section includes troubleshooting information that will help you test and check the circuits to localize and isolate problems.
4-48 Troubleshooting Procedures: Power Amplifier Procedures Begin troubleshooting by connecting an RF power meter and appropriate power load to the antenna connector. Connect the control cable and the power cable. Make sure the ignition sense lead is also connected to the positive lead of the power supply. Note that a regulated DC power supply capable of at least 30 A. is necessary to power a high-power Spectra transmitter. Remove the radio bottom cover.
Troubleshooting Procedures: Power Amplifier Procedures 4-49 Table 4-17. Power Control DC Voltage Chart RX MODE TX MODE LOCATION LOW TYP HI LOW TYP HI COMMENTS J1 1 0 0 2.0 3.2 2 0 2.0 7.0 10.0 Drive Voltage Current Sense + 3 10.8 13.6 16.5 10.0 13.0 16.0 4 0 0 0 9.2 9.4 9.8 5 10.8 13.6 16.5 10.0 13.0 16.0 6 7 0 — 8 — 1.2 — 0 Control Voltage Limit Keyed 9.4 A+ to Command Board Temp Sense (cutback begins at 3.3 V) — — — Key (no pin) 13.0 9.3 5.
4-50 Troubleshooting Procedures: Power Amplifier Procedures Table 4-17. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 16 5.0 5.7 6.4 5.0 5.7 6.4 5-V Series Pass Drive (6.4 at max current) 17 9.5 9.6 9.9 9.5 9.6 9.9 9.6-V Sense Input J1 18 7 7 19 5.7 5.7 20 4.9 5.0 5.1 4.9 5.0 21 1.2 1.2 22 0 0 23 0.9 24 2.9 25 v — 9.6 1.2 5-V Reg. Compensation Capacitor N.C. 5.1 9.6-V Reg. Compensation Capacitor N.
Troubleshooting Procedures: Power Amplifier Procedures 4-51 Table 4-17. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION LOW TYP HI LOW TYP HI COMMENTS J1 44 2.1 3.2 Q0500E 13.0 13.0 A+ - CR0500 Drop Q0501C 12.3 12.3 VQ0500E - B/E Drop Q0501E 0.2 0.2 V pin 23 - B/E Drop Q0503E 0 1.5 V pin 42 - B/E Drop (TX) Q0503C 13.6 9.0 Q0504B 13.6 12.9 Control AMP Reference A+ - B/E Drop (TX) Key the transmitter.
4-52 Troubleshooting Procedures: Power Amplifier Procedures Methods of analyzing individual stages of the power amplifiers are detailed below. Most of the stages are Class-C and must be analyzed under relatively high RF power levels. The following information should help in isolation and repair of the majority of transmitter failures. Testing Low-Level Amplifier (LLA) Circuitry Proper operation of the LLA can be checked by monitoring the voltage across resistor R5805.
Troubleshooting Procedures: Power Amplifier Procedures 4-53 NOTE: If it is necessary to replace Q5803, use a hot-air blower to remove and replace the part. It is important that the replacement device's case be properly soldered to its heatsink. Do so by flowing a small bead of solder around the rim of the device while it is clamped in the hot-air soldering device. The base and collector leads must be hand-soldered on the bottom side of the board.
4-54 Troubleshooting Procedures: Power Amplifier Procedures Installation of the PA board into the radio chassis must be done carefully. The PC board screws use a T-15 Torx bit and should be torqued to 6 to 8 inch-pounds. The device screws use a T-8 Torx bit and should be torqued to 6 to 8 inch-pounds. Always apply thermal compound to the area under the device flanges before installing the PA board. Current drain of the final amplifier may be checked by measuring the voltage across R5875 during transmit.
Troubleshooting Procedures: Power Amplifier Procedures 4-55 Control-Voltage-Limit Circuitry Test Disconnect J5901 (transmitter injection) from the PA input. With all other connections in normal condition, key the transmitter and monitor the control voltage at J1 pin 2. If the voltage exceeds 10.0 V, troubleshoot the control voltage limit circuitry. Current-Limiting Circuitry Test When ready to adjust current limit, decrease the relative current limit value with the keyboard per instructions.
4-56 Troubleshooting Procedures: Power Amplifier Procedures Low-Voltage Current Drain Cutback An additional circuit associated with the over-voltage protection circuit is the low-voltage current drain circuit. This circuit acts to reduce the transmitter current drain under conditions of low supply voltage. This action extends the available transmit time when, for example, the transmitter in a vehicular installation must be used when the engine is not running.
Troubleshooting Procedures: Power Amplifier Procedures 4-57 If, for diagnostic reasons, a chip component needs to be removed to facilitate testing, such as a series capacitor removed to allow for signal insertion, then the component(s) returned to the circuit should be new parts. The application of a soldering iron to many chip components will tend to cause leaching which could lead to failure.
4-58 Troubleshooting Procedures: Power Amplifier Procedures 8. If no failure is located from the previous checks, troubleshoot the power control circuitry. Table 4-19. DC Voltages and Input Power Chart Test Keyed 9.4 V 9.6 V CONTROL VOLTAGE DRIVE POWER IN (mW) A+ .V Transmit 9.4 9.6 See notea 30 13.0 Receive 0 9.6 0 0 13.0 a. Set initially to zero. Increase value until power equals 46 Wafts or 10.0 V maximum. Do NOT exceed 10.0 V.
Troubleshooting Procedures: Power Amplifier Procedures 4-59 Table 4-20. Power Control DC Voltage Chart RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI P0853 1 — — — — — — Key (no pin or wire) Control Voltage Limit 2 0 0 2.0 3.2 3 0 2.0 7.0 10.0 Drive Voltage Current Sense + 4 10.8 13.6 16.5 10.0 13.0 16.0 5 0 0 0 9.2 9.4 9.8 6 10.8 13.6 16.5 10.0 13.0 16.0 7 8 0 — 9 — 1.2 — 0 Keyed 9.4 A+ to Command Board Temp Sense (cutback begins at 3.
4-60 Troubleshooting Procedures: Power Amplifier Procedures Table 4-20. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 15 4.9 5.0 5.7 4.9 5.0 5.7 5-V Current Limit (limits at 5.7 V) 16 5.0 5.7 6.4 5.0 5.7 6.4 5-V Series Pass Drive (6.4 at max current) 17 9.5 9.6 9.9 9.5 9.6 9.9 9.6-V Sense Input 18 7 7 19 5.7 5.7 20 4.9 5.0 5.1 4.9 5.0 21 1.2 1.2 22 0 0 23 0.9 24 2.9 25 — — 9.6 1.2 5-V Reg.
Troubleshooting Procedures: Power Amplifier Procedures 4-61 Table 4-20. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 43 1.3 7.0 Loop Integrator Capacitor 44 2.1 3.2 Control AMP Reference Q0500E 13.0 13.0 A+ - CR0500 Drop Q0501C 12.3 12.3 VQ0500E - B/E Drop Q0501E 0.2 0.2 V pin 23 - B/E Drop Q0503E 0 1.5 V pin 42 - B/E Drop (TX) Q0503C 13.6 9.0 Q0504B 13.6 12.
4-62 Troubleshooting Procedures: Power Amplifier Procedures 3. Power Intermittently Low (or Zero) and Current Less than 1 A. When Power Drops - Check LLA stage. 4. Power Zero and Current Greater Than 2 A. - Check harmonic filter, antenna switch, matching circuits between driver and final stages, and matching circuits beyond final stage. 5. Power Zero and Current Less Than 1 A. - Check LLA/pre-driver circuitry. 4.5.2.2.
Troubleshooting Procedures: Power Amplifier Procedures 4-63 NOTE: The LLA voltages change with different control voltages. An example of LLA voltages with control voltage equal to 10.0 V and 6 V is shown. If Q5803 draws no current under normal conditions, then check for short or open input cable, or for defective parts in the transmit injection filter or matching circuitry between Q5801 and Q5803. If all of the above check out OK, then replace Q5803. 2. Testing Pre-Driver Circuitry.
4-64 Troubleshooting Procedures: Power Amplifier Procedures 5. Testing the Antenna Switch and Harmonic Filter Verify that most of this circuit is functioning properly by testing the receiver insertion loss as follows: - Apply a low-level signal source at the antenna connector. - Apply the conditions indicated in Table 4-19 for RX tests. - Measure the power at the receive coax. - If the difference between the input and output (insertion loss) is less than 1 dB, then the circuitry is functioning properly.
Troubleshooting Procedures: Power Amplifier Procedures 4-65 3. Control-Voltage-Limit Circuitry Test Disconnect J5901 (transmitter injection) from the internal transceiver chassis. This will require removal of the power amplifier assembly. With all other connections in normal condition, key the transmitter and monitor the control voltage at the node of R5811, C5814,L5808, and R5808. If the voltage exceeds 10.0 V, troubleshoot the control voltage limit circuitry. 4.
4-66 4.5.3 Troubleshooting Procedures: Power Amplifier Procedures 800 MHz Band 4.5.3.1 15 Watt and 35 Watt Power Amplifiers This information will help you troubleshoot the Spectra radio. Use this information, along with the Theory of Operation, to diagnose and isolate the cause of failures. The principle tools needed to troubleshoot a circuit to the component level are the schematic and the Theory of Operation.
Troubleshooting Procedures: Power Amplifier Procedures 4-67 4.5.3.1.2 PA Functional Testing To test the PA assembly for proper operation, perform the following steps: NOTE: The following instructions pertain to both the 15 Watt and 35 Watt power amplifiers. A distinction between the two PA’s is given only where necessary. 1. Disassemble the PA assembly from the radio, leaving the power cable connected to the rear connector. Replace the 15-Watt PA shield (or the 35-Watt PA shield and cover).
4-68 Troubleshooting Procedures: Power Amplifier Procedures Table 4-23. DC Voltages and Input Power Chart Test Keyed 9.4 V 9.6 V CONTROL VOLTAGE DRIVE POWER IN (mW) A+ .V Transmit 9.4 9.6 See notea 0.1 13.0 Receive 0 9.6 0 0 13.0 a. Set initially to zero. Increase value until power equals 17 wafts(15-Watt radio) or 38 Watts (35-Watt radio) or 11.0 V maximum. 3. Apply the required input power via adapter cable 30-80373B27 or equivalent.
Troubleshooting Procedures: Power Amplifier Procedures 4-69 Table 4-24. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI U0500 1 0 2 3 0 0 0 0 0 4 0 5 0 6 0 1.5 0 0 3.2 0 Ground Control AMP Input 0 0 0 0 2 3.2 0 Control AMP Input (not used) Control Voltage Limit (cutback at 3.3 V) N.C. 3.0 4.5 1.5 3.0 4.5 Power Set from D-A (max power at 1.5 V) 7 0 0 1.5 3.0 4.5 Power Set Buffer Out 8 0 1.3 3.5 6.
4-70 Troubleshooting Procedures: Power Amplifier Procedures Table 4-24. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS LOW TYP HI LOW TYP HI 29 — — — — — — 9.6-V Programming (N.C.) 30 — — — — — — 9.6-V Programming (N.C.) 31 0 0 0 0 0 0 Ground 32 10.8 13.6 16.5 10.0 13.0 16.0 33 4.0 5.0 0 0.2 34 0 1.3 35 0 0 36 0 0.
Troubleshooting Procedures: Power Amplifier Procedures 4-71 Table 4-25. Antenna Switch DC Voltage Chart TYPICAL RX TYPICAL TX NO PREDRIVE ANODE 0 1.6 TX Series P.I.N. diode CATHODE 0 0.8 (on in TX mode) ANODE 0 0.8 TX Shunt P.I.N. diode CATHODE — — (on in TX mode) ANODE 5.15V <0.2 CATHODE 4.45V 8.7 COLLEC 5.15V <0.2 LOCATION CR9920 CR9921 CR9922 Q9920 COMMENTS RX Series P.I.N. diode (off in TX mode) 4.5.3.1.
4-72 Troubleshooting Procedures: Power Amplifier Procedures 4.5.3.1.4 Isolating Failures Methods of analyzing individual stages of the Power Amplifiers are detailed below. Most of the stages are Class C and must he analyzed under relatively high RF power levels. Generators capable of such levels may not be available in all service shops, therefore the tests below are arranged in order of increasing power. This tends to allow the preceding stage to be the source of RF power for testing the next stage.
Troubleshooting Procedures: Power Amplifier Procedures 4-73 When testing is complete, replace any capacitors or resistors that were removed for testing with new parts. 3. Testing the Final Stage (35-Watt Models Only) The final stage is capable of producing over 50 Watts. Be sure to protect power measuring equipment with series attenuation. 30 dB is usually adequate. 15 Watts are needed to drive the final stage.
4-74 Troubleshooting Procedures: Power Amplifier Procedures Additional antenna switch tests are: - Check CR9922 with an ohmmeter for forward and reverse continuity. - In the transmit mode, adjust control voltage for 38 Watts at the antenna connector. Check for less than 10 mW at the end of the receive input cable. If power exceeds 10 mW, then check CR9922 and associated circuitry. Receiver sensitivity can degrade if power at this port exceeds 10 mW.
Troubleshooting Procedures: Power Amplifier Procedures 4-75 6. Power-Leveling Circuitry Test With the radio connected for power measurements, vary the line voltage from 12.5 to 16 V. The power should not vary more than 3 Watts. At a line voltage of 13.6 V, vary the frequency using the three test modes. If power varies more than 3 Watts, measure the detected voltage on P0853, pin 9. If this voltage varies more than 0.
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Chapter 5 Troubleshooting Charts 5.1 Introduction This chapter contains detailed troubleshooting flowcharts. These charts should be used as a guide in determining the problem areas. They are not a substitute for knowledge of circuit operation and astute troubleshooting techniques. It is advisable to refer to the related detailed circuit descriptions in the theory section prior to troubleshooting a radio. 5.
5-2 Troubleshooting Charts: List of Troubleshooting Charts Table 5-1. List of Troubleshooting Charts (Continued) Chart Number Description Page Number Chart C.19 No RX Audio 5-14 Chart C.20 No TX Modulation 5-15 Chart C.21 Key Load Fail 5-16 Chart C.22 800 MHz Receiver Front-End Hybrid 5-17 Chart C.23 UHF Receiver Front-End Hybrid 5-17 Chart C.24 VHF Receiver Front-End Hybrid 5-18 Chart C.25 ASTRO Spectra Plus VOCON Power-Up Failure 5-19 Chart C.
Troubleshooting Charts 5-3 Bad SINAD. Bad 20Db Quieting. No Recovered Audio. Note: Inject Modulated On Carrier Frequency Signal As Required. Inject 1st IF into Johnson connector on RF board IF Freqs: 109.65MHz Check RX Front End. Yes Audio Heard? No Check 2nd VCO "Second VCO Checks" Yes VCO Locked? No 2.1MHz Check At Pin 19 U301? No "Display Flashes "FAIL 001"" Yes 14.4MHz at ABACUS U301 Pin 15? No Check U301 Voltages, Programming, & 14.4MHz VCO Components.
5-4 Troubleshooting Charts Control Head Display: "FAIL 01/82" "FAIL 01/84" "FAIL 01/88" "FAIL 01/02" START Note 1: See Control Head Troubleshooting Chart In Spectra Detailed Service Manual. Note 2: See VOCON Board Troubleshooting Chart. Control Head Display: "FAIL 01/90" or Blank START Replace and/or Reprogram VOCON Board. (See Note 2) Check Busy In P501-20 (Press Control Head Button). Check Voltages UNSW +5V, SW +5V, +9.6V. Check U522-13 (Press Control Head Button).
Troubleshooting Charts 5-5 1 Radio Power-Up Failure. Synopsis This failure assumes the radio fails to power up correctly and does not send any Power up failure messages via the display or serial bus. Some basic failure modes: 1) Radio is inhibited. 2) Battery voltage is low. 3) A problem exists with a supply or system clock. 4) Host C code is corrupted. 5) Host FLASH or RAM is faulty. 6) Corrupted host C configuration register. 7) Host C or SLIC is faulty.
5-6 Troubleshooting Charts Host C Bootstrap Failure. Synopsis The host C bootstrap mode is used during reprogramming of the host C and DSP FLASH ROMs. Refer to appropriate Theory of Operation section for description of bootstrap operation. Since the operating code is downloaded through the serial bus instead of from the ROM and is initially executed in the C internal RAM, this is a good method of verifying operation of the C. Basic failure modes: 1) Necessary supplies, grounds, system clocks not present.
Troubleshooting Charts 5-7 Fail 01/81 Host ROM Checksum Failure Visually inspect all leads to U205 and U210 with a 5x glass. Fail 01/90 General Hardware Failure No Repair opens. Check Command Board for 9.6 V and 5.0 VDC. No Yes Replace Command Board. Use ohmmeter to electrically verify following signal connections to source IC: Signal @ U205/U210 Source HD0-HD7 U204 HA0-HA13 U204 HA14OUT,HA15OUT U206 HA16,HA17 U206 ROMCS1*,ROMCS2* U206 OE*,MEMR/W* U206 VCC +5V VSS GND Yes Replace VOCON Board.
5-8 Troubleshooting Charts Fail 01/82 or 002 External EEPROM Checksum Failure Use ohmmeter to electrically verify following signal connections to source IC: Signal @ U201 Source HD0-HD7 U204 HA0-HA13 U204 HA14OUT U206 EE1CS* U206 OE*,MEMR/W* U206 RESET* U407 VCC +5V VSS GND No Repair opens. Fail 01/84 SLIC Init Failure Synopsis This failure indicates the External EEPROM data containing mostly customer specific channel/mode information is incorrect.
Troubleshooting Charts 5-9 Fail 01/88 Host C External RAM Failure. Synopsis This failure indicates a failure in the C external SRAM at power up test. Some basic failure modes: 1) Missing supply or ground to SLIC. 2) Open in parallel address bus, data bus or associated select lines between the host C and the SLIC and the SRAM. 3) 4xECLK missing to the SLIC. 4) SLIC is faulty. 5) Improper decoding logic due to open or failure of U211 AND logic gate. 6) SRAM is faulty.
5-10 Troubleshooting Charts Fail 02/A0 ADSIC Checksum Failure Use ohmmeter to electrically verify following signal connections to source IC: Signal @ U406 Source D8-D23 U405 A0-A2,A13-A15 U405 PS*,RD*,WR* U405 SELx,RSTx U204 SPD,SCLK U204 1 VDDD,VDD1,VDD2, VDD3 VDDAb,VDDA VSSD,VSS1,VSS2, VSS3 2 VSSA,VSSAb +5V +5VA GND AGND R402 ABI 1 Note: Finding an open at VDDx may be difficult because of low isolation between supply pins. 2 Also measure continuity between GND and AGND through jumper JU407.
Troubleshooting Charts 5-11 Fail 02/88 DSP SRAM U414 Failure Synopsis On power-up the DSP writes data to the device and then verifies the data. This failure indicates the DSP SRAM failed this pattern/checksum test. U414 is selected by the DSP (U405) address bus with the addition of the OR logic gate U415. Basic failure modes are as follows: 1) Some problem exists (open/shorts) with the external address/data bus.
5-12 Troubleshooting Charts Fail 02/82 DSP SRAM U402 Failure Use ohmmeter to electrically verify following signal connections to source IC: Signal @ U402 Source D0-D23 U405 A0-A12 U405 WR*,RD* U405 E1* U405-A15 E2 U405-A13 X/Y*,V/S* GND VCC +5V VSS GND Repair opens. No Connections good? Yes Check for ADSIC programming checksum error. Refer to section on Fail 02/A0. Chart C.11 Yes ADSIC checksum error? Refer to a Fail 02/84.
Troubleshooting Charts 5-13 Fail 09/10 Secure Hardware Failure Synopsis This failure relates only to secure equipped radios and indicates a power up self-test failure for the secure module. More specifically this failure indicates a failure in communications between the Host C and secure module. The secure module is not considered field repairable so troubleshooting is limited to verifying a problem with the module and replacing.
5-14 Troubleshooting Charts No Receive Audio Verify signal at output of U524 pin 2. Verify signals per Fig. W2 at points indicated. Set radio to test mode CSQ. Inject a 1KHz modulated signal at the carrier. Frequency at -60dBm level with 3KHz deviation. No Signals present? Replace U406. Yes Verify standard bias per Table 6. No No Verify signal at input of U524 pin 1. Yes Signal present? Verify signal present at U450 pin 2.
Troubleshooting Charts 5-15 1 No Tx Modulation 2 Verify 1KHz signal present at U401. Verify standard bias per Table 6. Isolate and repair problems, See Chart C.5. No Standard bias OK? Signal present? Synopsis This failure indicates a lack of transmit modulation with the fault lying with the VOCON or Command board. It assumes no power up codes were displayed. Since all modulation modes occur through the same path, this failure applies to digital/ PL,DPL, etc.
5-16 Troubleshooting Charts Keyload Failure Kit NTN1146 NTN1152 NTN1153 NTN1158 NTN1147 NTN1367 NTN1368 NTN1369 NTN1370 NTN1371 NTN1562 NTN1563 NTN1564 NTN1565 NTN1566 Verify the use of the correct keyloader per the following table: Secure Board Kit(s) KVL Kit(s) Encryption NTN7770 T3010DX DVP NTN7771 T3011DX DES NTN7772 T3011DX DES-XL NTN7773 T3012DX DVI-XL NTN7774 T3014DX DVP-XL NTN7329 T3012DX & T3010DX DVI-XL & DVP NTN7332 T3011DX & T3010DX DES-XL & DVP NTN7331 T3011DX & T3014DX DES-XL & DVP-XL NTN7
Troubleshooting Charts 5-17 START START Check Module Gain: Inject On-Channel Signal (851-870 MHz) of -20dBm at J9127: Measure Level 109.
5-18 Troubleshooting Charts START Check Module Gain: Inject 160MHz -20dBm at J9127 Measure at IF Output Measure Transceiver Sinad by Injecting Signal at J9127 Is Sinad Yes <-120 with Preamp <-117 nonPreamp ? No Problem with RX Front End or RF Board Is >-13 with Yes Preamp; >-22 NonPreamp ? Recheck RF Board and Transceiver Sinad No No Measure Sinad Inject 106.
Troubleshooting Charts 5-19 Verify Standard Bias per Table (xref to standard operating bias table) Standard Bias OK? No See Chart C.
5-20 Troubleshooting Charts Check for 1.
Troubleshooting Charts 5-21 Inspect and Repair Repair proper components U202 Inject a 1kHz tone into MIC with sufficient amplitude to produce 3kHz of deviation, PTT radio No Check 5V supply of U202-8 and GND U202-4 Amplitude of Waveform may vary Measure waveform at TP208, should match Figure 6-13 No Yes OK? Make sure the following components are placed and soldered correctly: U202, R207, R208, C216, R209, R226, C223, C217 Yes Measure waveform at R208 (left) should match Figure 6-13 No Wavefo
5-22 Troubleshooting Charts A Inspect U201 OK? No Repair component Yes Check Patriot clocks C326 - T1 - 16.8MHz R428 - T2 - 32kHz Measure waveform at U201-39 should match Figure 6-12 16.8MHz Clock Repair regulator circuit Repair components No Yes No Waveform correct? No Inspect R200, R201, and C201 OK? Yes Yes OK? Inspect and repair Patriot IC - U300 Repair oscillator circuit OK? No Yes Repair U201 Check SSI connections per Figure 5.
Troubleshooting Charts 5-23 C B Inspect U402, also check 3V at pin6 and GND at pin 15 Inspect U501 No OK? Repair U402 No OK? Repair U501 Yes Yes Is problem with Keyed9.4_EN or TXPA_EN Inspect U404, also check 5V at pin8 and GND at pin 4 TXPA_EN Check for GND at J501-14 Yes Present? Defective PCB No OK? No Keyed9.
5-24 Troubleshooting Charts Put the radio into Test mode (CSQ 1). Connect RF Signal Generator to the RF input of the radio. Use Dev=3kHz, Amplitude=-47dBm and Freq=851.025MHz D Amplitude of waveform may vary Measure waveform at TP403, should match Figure 6-17 Make sure that R407, R400, C405 are placed and values are correct Yes OK? Measure waveform at the Vocon Connector, J501 pin 40.
Troubleshooting Charts 5-25 Make sure the Secure Module is connected to the Plus VOCON board and the radio is ON Measure the voltage at pins 1, 2 and 20 on the secure connector. The voltage reading should be between 10V and 13V No Voltages correct? Measure voltage on Q600, pin 5. Voltage should read between 10V and 13V Yes Voltage correct? No Verify placement, soldering of J501 connector Yes Measure waveforms on P1 (secure connector) at pins 7, 8, 9, and 10.
5-26 Troubleshooting Charts Make sure the Secure Module is connected to the Plus VOCON board and the radio is ON Synopsis This failure relates only to secure equipped radios and indicates a failure to load a key with the KVL indicated by the message “xFail” and keyfail tone. Typical failure modes would be: 1) Keyload line not connected properly. 2) Use of wrong KVL or KVL cable. 3) Failure of Secure Module. Replace Secure Module Connect the Key Loader and download the appropriate secure key.
Chapter 6 Troubleshooting Waveforms 6.1 Introduction This chapter contains images of waveforms that might be useful in verifying operation of certain parts of the circuitry. These waveforms are for reference only; the actual data depicted will vary depending upon the operating conditions. 6.
6-2 Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W2: DSP SSI Port RX Mode 2893 Acquisitions T Tek stopped: Ch1 Freq 19.991kHz Low signal amplitude 1 2 T 3 5.00V 5.00V Ch1 Ch3 Ch2 5.00V M 20.0us Ch1 2.2 V MAEPF-24377-O W2: DSP SSI Port RX mode. Receiving 1KHz tone @ 3KHz deviation, -60dBm. Trace 1 - RFS Trace 2 - RXD 1 Trace 3 - SCKR (2.4/0.600MHz) Note 1: Typically SCKR is a 2.4 MHz clock. In low power modes, as shown here, SCKR is 600KHz.
Troubleshooting Waveforms: ASTRO Spectra Waveforms 6-3 Waveform W4: ABACUS Programming at Mode Change 13 Acquisitions T Tek stopped: Ch1 Freq 74.610kHz T 1 Ch1 2.00V M 10.0us Ch1 W4: ABACUS programming captured during mode change. Trace 1 - (ADSIC) SBI 2.2 V MAEPF-24379-O Waveform W5: ABACUS/ADSIC Interface Tek stopped: 34513 Acquisitions T T Ch1 Freq 2.251920 MHz Low resolution 1 2 3 Ch1 Ch3 2.00V Ch2 500mV 500mV M 5.00us Ch1 W5: ABACUS/ADSIC Interface.
6-4 Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W6: SPI Bus Programming ADSIC 18 Acquisitions T Tek stopped: T Ch1 Freq = Hz No period found T 1 T 21 T T 31 Ch1 Ch3 5.00V 5.00V Ch2 5.00V Ch1 M 50ns Ch1 W6: SPI Bus Programming ADSIC. Trace 1 - ADSIC_SEL* Trace 2 - SPI_SCK Trace 3 - MOSI Note: These waveforms are typical to any device on the SPI bus. 2.2 V MAEPF-24381-O Waveform W7: Receive Audio Tek stopped: 103 Acquisitions T T 1 Ch1 Freq 7.
Troubleshooting Waveforms: ASTRO Spectra Waveforms 6-5 Waveform W8: Transmit Audio Tek stopped: 507 Acquisitions T T 1 Ch1 Freq 7.9872kHz Low signal amplitude T 2 3 4 T 5.00V 300mV Ch1 Ch3 Ch2 500mV Ch4 100mV M 200us Ch1 1.5 V W8: Transmit Audio. 1KHz Tone which provides 3KHz deviation. Trace 1 - IRQB @ DSP (8KHz) Trace 2 - MODIN Trace 3 - MIC @ node P502/R415 Trace 4 - MAI @ U406 MAEPF-26078-O Waveform W9: Power-Down Reset Tek stopped: 1 Acquisitions T T 1 T 2 Ch1 2.00V Ch2 2.
6-6 Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W10: ADSIC 2.4 MHz Reference 493 Acquisitions Tek stopped: T Ch1 Freq 2.4038MHz T 1 Ch1 2.00V M 200ns Ch1 1.64 V W10 ADSIC 2.
Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 6.3 6-7 ASTRO Spectra Digital Plus VOCON Board Waveforms This section contains images of waveforms specific to the ASTRO Spectra Digital Plus VOCON board. These waveforms might be useful in verifying operation of certain parts of the circuitry. These waveforms are for reference only; the actual data depicted will vary depending upon the operating conditions.
6-8 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 16.8 MHz Clock Waveform Trace 1 — TP401 — 16.
Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 6-9 Differential ADDAG Output Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U201 — 4 Trace 2 — U201 — 5 TX SSI Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U201 — 33 - Data Trace 2 — U201 — 35 - Frame Sync Trace 3 — U201 — 34 - Clock 68P81076C25-C July 1, 2002
6-10 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms SPI Bus Waveform Radio Power Up Trace 1 — U201 — 41 - Data Trace 2 — U201 — 43 - Chip Select Trace 3 — U201 — 42 - Clock TX 1 kHz Tone Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U402 — 17 July 1, 2002 68P81076C25-C
Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 6-11 Serial Audio Port Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U402 — 7 - Frame Sync Trace 2 — U402 — 11 - Clock Trace 3 — U402 — 13 - Data RX Audio Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Trace 1 — U402 — 2 68P81076C25-C July 1, 2002
6-12 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms RX BBP Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Trace 1 — TP221 — Frame Sync Trace 2 — TP223 — Data Trace 3 — TP219 — Clock Secure Interface Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Secure Mode Trace 1 — P1 — 8 - Data Trace 2 — P1 — 10 - SS Trace 3 — P1 — 9 - Clock July 1, 2002 68P81076C25-C
Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 6-13 8 kHz Frame Sync for Security Circuitry Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Secure Mode Trace 1 — U601 — 5 68P81076C25-C July 1, 2002
6-14 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms This Page Intentionally Left Blank July 1, 2002 68P81076C25-C
