Instruction Manual 1720/1721 Vectorscope (S/N B060000 & Above) 070-5846-07 Warning The servicing instructions are for use by qualified personnel only. To avoid personal injury, do not perform any servicing unless you are qualified to do so. Refer to all safety summaries prior to performing service. www.tektronix.
Copyright E Tektronix, Inc., 1986, 1990, 1993, 1995. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supersedes that in all previously published material. Specifications and price change privileges reserved. The following are registered trademarks: TEKTRONIX and TEK. For product related information, phone: 800-TEKWIDE (800-835-9433), ext. TV. For further information, contact: Tektronix, Inc., Corporate Offices, P.O.
WARRANTY Tektronix warrants that this product, that it manufactures and sells, will be free from defects in materials and workmanship for a period of three (3) years from the date of shipment. If any such product proves defective during this warranty period, Tektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in exchange for the defective product.
Table of Contents Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i viii x Section 1 Introduction and Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents Power Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mains Frequency and Voltage Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operating Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X Y INPUT Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Auxiliary Connector . . . . .
Table of Contents Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DIAGRAM 6 CONTROL CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Z-Axis Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trace Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents iv Bezel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Graticule Light Removal and Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CRT Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replacement of the CRT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Removing the Rear Panel . .
Table of Contents List of Figures Figure 2-1: Control and indicator locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 2-2: 1720/1721 rear panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 2-3: Signal connection for the Operator’s Checkout Procedure. . . . . . . . . . . . . . . . . . Figure 2-4: 1720/1721 typical vector display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents vi Figure 4-2: Block diagram of the Phase Lock Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4--7 Figure 5-1: Rear view of Remote plug connections.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 5-2: Loop--through connection of black burst signal to both EXT REF and CH-B. . . Figure 5-3: Using the vector graticule --3 dB markings to measure bandwidth. . . . . . . . . . . .
Table of Contents List of Tables 1720/1721 Table 1-- 1: Signal Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 1-- 2: Vector Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 1-- 3: XY Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 1-- 4: CRT Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Safety Summary Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. To avoid potential hazards, use this product only as specified. Only qualified personnel should perform service procedures. To Avoid Fire or Personal Injury Use Proper Power Cord. Use only the power cord specified for this product and certified for the country of use. Connect and Disconnect Properly.
General Safety Summary Symbols and Terms Terms in this Manual. These terms may appear in this manual: WARNING. Warning statements identify conditions or practices that could result in injury or loss of life. CAUTION. Caution statements identify conditions or practices that could result in damage to this product or other property. Terms on the Product. These terms may appear on the product: DANGER indicates an injury hazard immediately accessible as you read the marking.
Preface This manual documents the TEKTRONIX 1720/1721 Vectorscope. Information that applies to all instruments in the series refers to the 1720/1721. Information that applies to only specific instruments within the series refers to the model numbers of those instruments (i.e., 1720, 1721). The information in this manual is intended for instrument operators and service technicians. Operators are assumed to be familiar with basic television terms and measurements.
Preface Section 9, Diagrams, contains servicing illustrations. These include adjustment locations, circuit board part locations, a block diagram, schematic diagrams, and waveforms. Parts locating tables are included that cross--reference the circuit board illustrations and the schematic diagrams. Section 10, Replaceable Mechanical Parts, includes ordering information and part numbers for all replaceable mechanical parts. This parts list is referenced to an exploded view mechanical drawing.
Preface xii
Introduction and Specifications
Section 1 Introduction and Specifications The TEKTRONIX 1720/1721 is an 8-1/2”--wide by 5-1/4”--high Vectorscope, weighing 8-1/2 pounds. Both the 1720 (System M, NTSC) and the 1721 (System I, B, etc., PAL) versions can be powered from an ac source or, with the addition of a field upgrade kit (1700F10), from 12 Vdc. The crt occupies approximately two-thirds of the front-panel area, with the control panel taking up the remainder of the space.
Introduction and Specifications Accessories The 1720/1721 is shipped with a set of accessories that are needed for its installation or day-to-day operation. These are the “Standard Accessories.” They are physically packaged in a small, cardboard carton within the packing box. In addition to the Standard Accessories, there are other accessory items that can be purchased from Tektronix, Inc., which will either enhance operation or help to customize the installation.
Introduction and Specifications Safety Information 1720/1721 instruments are intended to operate from an ac power source that will not apply more than 250 V rms between the supply conductors or between either supply conductor and ground. A protective ground connection by way of the grounding conductor is essential for safe operation. The 1720/1721 was tested for compliance in a cabinet.
Introduction and Specifications Table 1- 1: Signal input Step number Characteristics Performance requirement Supplemental information Return loss (75Ω) Video inputs (CH A, CH B) EXT REF At least 40 dB from 50 kHz to 6 MHz. Loop-through terminated in 75W. Input 11 in use or not in use, instrument power on or off, all deflection factor settings. Crosstalk between channels Greater than 70 dB of isolation between channels. Measured at FSC between Channel A, Channel B, and EXT REF.
Introduction and Specifications Table 1- 2: Vector mode (cont.) Characteristic Performance requirement Subcarrier regenerator NTSC pull-- in range PAL pull-- in range Phase shift with burst amplitude change ±50 Hz of Fsc ±10 Hz of Fsc 6 ±2° from Fsc to (Fsc + 50 Hz) or Fsc to (Fsc - 50 Hz) ±2° from Fsc to (Fsc + 10 Hz) or Fsc to (Fsc - 10 Hz) 6 ±2° from nominal burst amplitude to ±6 dB. 6 ±0.5° Phase shift with VAR GAIN control ±1° as gain varies from 3 dB to - 6 dB.
Introduction and Specifications Table 1- 3: XY Mode Characteristic Performance requirement Input Supplemental information Step number DC Coupled differential inputs through rear-panel REMOTE connector. Input amplitude 2 to 9 Vp-- p Maximum input voltage ±15 V peak signal plus DC. Frequency response DC to greater than 500 kHz. 3 dB point. 14 High gain mode DC to greater than 100 kHz. 3 dB point. Not a differential input, minus inputs must be grounded.
Introduction and Specifications Table 1- 6: Environmental Characteristics Characteristic Supplemental information Temperature Non-operating Operating - 55 to +75 °C 0 to +50 °C Altitude Non-operating Operating To 50,000 feet To 15,000 feet Vibration - operating 15 minutes each axis at 0.015 inch, frequency varied from 10-55-10 Hz in 1-minute cycles with instrument secured to vibration platform. Ten minutes each axis at any resonant point or at 55 Hz if no resonant point is found.
Introduction and Specifications Table 1- 8: Certifications and Compliances (cont.) Category Standards or description Australia/New Zealand Declaration of Conformity - EMC Complies with EMC provision of Radiocommunications Act per the following standard(s): AS/NZS 2064.1/2 Industrial, Scientific, and Medical Equipment: 1992 AS/NZS 3548 Information Technology Equipment: 1995 FCC Compliance Emissions comply with FCC Code of Federal Regulations 47, Part 15, Subpart B, Class A Limits.
Operating Instructions
Section 2 Operating Instructions These instructions provide information about the front-panel controls, rear-panel connectors, the Operator’s Familiarization/Checkout Procedures, and discussions about vector and audio measurements using the 1720/1721. Front-Panel Controls and Indicators The front-panel controls and indicators consist of momentary contact push-button switches, variable controls, and backlit switch selections. See Figure 2-1 for the control and indicator locations.
Operating Instructions There are three push-button switches, located in the INPUT block, that have an extra function. The extra function is accessed by holding the switch down for approximately one second. The operating selection reverts to the top of the listed functions when the push button is repushed to exit this extra function, with the exception of TEST, which reverts to its original state when exiting. INPUT 1. MODE A momentary push-button switch that toggles between the vector and XY displays.
Operating Instructions 5. BARS A momentary contact push-button switch that toggles between correct gain for displaying 75% and 100% amplitude color bar signals, using a single set of vector targets. Burst targets for both 75% and 100% amplitude color bars are on the graticule. Back lighted nomenclature, with rectangular indicators, lights to indicate that the 1720/1721 is set up to measure color bars. PHASE 6.
Operating Instructions 12. POWER Turns on and off external power to the 1720/1721. Contains a mechanical indicator that indicates the status of the POWER switch, even when the mains power is disconnected or shut down from another location. 13. ROTATE A 270° rotation screwdriver adjustment that aligns the display with the graticule. 14. GAIN CAL A 270° rotation screwdriver adjustment that sets the amplifier gains in the Vector Mode. 15.
Operating Instructions 1 2 3 4 VECTORSCOPE PIX MON OUT AUXILIARY CONTROL IN CH-- A INPUT CH-- B X Y INPUT EXT REF 75 OHM LOOP-- THROUGH 8 7 6 5 Figure 2-2: 1720/1721 rear panel. 1. AC POWER A standard ac plug receptacle for the 120 or 220 Vac power mains. Plug is compatible with any of the three power cord options available for the 1720/1721 Vectorscope. 2.
Operating Instructions 5. EXT REF A bridging loop-through input (compensated for 75Ω) for synchronizing signals. As factory shipped, the input signal may be black burst or composite video. Changing a pair of internal plug jumpers makes it possible to use CW Subcarrier as an external reference; however, horizontal (line) sync must be present on the CH-A INPUT for synchronization. External reference is selected by the front-panel REF switch. 6.
Operating Instructions switch can be used independently, even though the instrument is in the AUXILIARY mode. REF Switching REF switching allows the 1730-Series to select either INT or EXT reference. It will not switch to TEST when the 1730-Series is switched to CAL. Reference will automatically be switched to EXT if the INPUT is switched to BOTH (from either waveform monitor or vectorscope). If the 1720/1721 REF switch is in TEST, the 1730-Series switching will not take it out of that mode.
Operating Instructions OPERATOR’S CHECKOUT PROCEDURE The following procedure is provided as an aid in obtaining a display on the 1720/1721 Vectorscope, and may be used as a check of basic instrument operation. Only instrument functions are checked in this procedure. All checks can be made with a cabinet on and it is necessary to have all internal jumpers in the factory-set position.
Operating Instructions 75% Ampl. 0% Setup ---- PAL Modulated Staircase (Flat Field, 10 Step) Black Burst Signal (Sync and Burst only) If the XY operation of the 1720/1721 is to be checked, an audio signal is required. See the following: Audio Signal: (About 2 V between 1 and 100 kHz.) 1720/1721 (rear) 1410-- Series (rear) Color bar signal Mod staircase 75Ω Termination Figure 2-3: Signal connection for the Operator’s Checkout Procedure. 2.
Operating Instructions V R g cy 50° 40° MG 30° Q 20° d∅ 10° 20% dG YL 10° b 75% 100% U 0° 10° 10% dG B yl 100% 75% G mg CY -I r Figure 2-4: 1720/1721 typical vector display. Adjust the SCALE illumination control for the desired brightness. Note that the internal waveform graticule should be illuminated.
Operating Instructions V R g cy 50° 40° MG 30° Q 20° d∅ 10° 20% dG YL 10° b 75% 100% U 0° 10° 10% dG B yl 100% 75% G mg CY -I r Figure 2-5: Modulated staircase waveform shown on a 1721. A 1720 would have what would appear to be an intensified burst.
Operating Instructions 4. Select Input Select the Channel B input for a display of the modulated staircase signal. See Figure 2-5. Push in and hold the INPUT button until both the CH-A and CH-B indicators are lit, and check for a display of both vectors and modulated staircase. See Figure 2-6. V R g cy 50° 40° MG 30° Q 20° d∅ 10° 20% dG YL 10° b 75% 100% U 0° 10° 10% dG B yl 100% 75% G mg CY -I r Figure 2-6: Color bar and modulated staircase signals both displayed on a 1721.
Operating Instructions 1720/1721 (rear) 1410-- Series (rear) Color bar signal Black burst 75Ω Termination Figure 2-7: Connection for using black burst signal for External Reference. Push the REF button and check that the front-panel EXT indicator lights. Check for a stable display of vectors (CH-A INPUT). Push and hold the REF button until the front-panel TEST indicator lights. Check for a test circle display. See Figure 2-8. Leave the 1720/1721 REF in TEST.
Operating Instructions 2- 14 1720/1721
Operating Instructions 8. Variable With the test circle displayed, push the VARIABLE push button and check that the VARIABLE ON indicator lights. Rotate the VARIABLE control fully clockwise and check that the display increases in size. Rotate the VARIABLE control fully counterclockwise and check that the outer circle is inside the outer (Red and Cyan) targets. Push the VARIABLE push button and check that the test circle is on the outer targets and that the front-panel VARIABLE ON indicator is off. 9.
Operating Instructions Color Measurements In color television, the visual sensation of color is described in terms of three qualities: luminance, hue, and saturation. Luminance. Luminance is brightness as perceived by the eye. As the eye is most sensitive to green and least to blue light of equal energy, green is a bright color and blue is a dark color as conveyed by the luminance signal to monochrome TV receivers. Chrominance. Chrominance is measured in terms of hue and amplitude.
Operating Instructions iV F=U+iV F*=U-- iV RED CYAN GREEN F MAGENTA 0.4 0.2 YELLOW YELLOW 45° a -a - 0.2 45° BLUE 0.2 U BLUE - 0.2 - 0.4 GREEN MAGENTA F* RED CYAN Figure 2-10: PAL standard color phase Vector diagram. Saturation is the degree to which a color (or hue) is diluted by white light in order to distinguish between vivid and weak shades of the same hue. For example, vivid red is highly saturated and pastel red has little saturation.
Operating Instructions dᡢ 10° 20% dG YL 75% 100% 0° 10° 10% dG yl WITH SETUP 100% WITHOUT SETUP 75% Figure 2-11: Partial 1720 graticule showing the 75% amplitude burst target, with and without setup compensation. Encoding. The hue and color amplitude information in the color television system is carried on a single subcarrier frequency: 3.579545 MHz for NTSC and 4.43361875 MHz for PAL. These signals, in modulated subcarrier form, are called chrominance.
Operating Instructions Decoding. To recover the hue information, phase demodulators are employed in the vectorscope. The phase reference is the color subcarrier, which is regenerated by an oscillator in the instrument. The oscillator is locked in both phase and frequency to the incoming color burst signal. The vectorscope displays the relative phase and amplitude of the chrominance signal on polar coordinates.
Operating Instructions 60.68° 70.68° 2.5° 2.5° 50.68° cy 50° 2.5 IRE 40° MG 10° 30° 20% 20% 10° Q 20° 10° b U Figure 2-13: Fine detail of the 1720 graticule magenta target. On the 1721 graticule, each chrominance vector related to the +V burst terminates in targets that are in the shape of two boxes (a small box inside a large box). See Figure 2-14. The large box represents ±10° centered on the exact chrominance phase and ±20% of chrominance amplitude centered around 100% standard amplitude.
Operating Instructions 70.65° 60.65° 3° 3° cy 50.65° 50° 5% 40° MG 10° 20% 20% 10° 30° Q 20° 10° b U Figure 2-14: Fine detail of the 1721 graticule target. On the 1720, the small marks at intervals along the I and Q axes denote the amplitudes of the chrominance components (see Figure 2-15). On the 1721, the small marks at intervals along the U and V axes denote the amplitudes of the U and V chrominance components (see Figure 2-16).
Operating Instructions V 90° +V BURST 135° R cy MG g Q YL b yl B U 0° 180° - V BURST 225° G mg CY r 270° Figure 2-16: Simulation of a 1721 graticule showing the relationship between amplitudes on the U and V axes and the locations of the color vector targets. The horizontal and vertical axes of the vector graticule contain markings for checking Vector Mode bandwidth. A subcarrier frequency sine wave whose amplitude places it on the outer compass rose is used as a reference.
Operating Instructions dᡢ 10° 20% dG YL 75% 100% 0° 10° 10% dG yl WITH SETUP 100% WITHOUT SETUP 75% Figure 2-17: A simulation of a part of the 1720 graticule showing the differential phase and gain measurement scales with approximately 10° differential Phase (dP). Differential gain (dG) and differential phase (dφ) measurements can be made using the graticule markings located at the outer edge of the B-Y axis (1720) or --U axis (1721).
Operating Instructions dᡢ 10° 20% dG YL 75% 100% 0° 75% AMPLITUDE BURST TARGETS 10° 10% dG yl 100% 75% Figure 2-18: Simulation of the 1721 Differential Gain and Phase graticule showing approximately 10 % differential Gain (dG). X Y Measurements Any oscilloscope, including vectorscopes that have identical X and Y amplifiers, can be used to make accurate stereo audio phase measurements.
Operating Instructions signal at a time and adjusting its gain to correspond to the appropriate axis (horizontal to the X axis and vertical to the Y axis). Once both signal gains are normalized they can be displayed in the XY Mode and the relative stereo phase measured. Looking at Incidental Carrier Phase Modulation The High-Gain X and Y inputs of the 1720/1721 can be used to look at ICPM (Incidental Carrier Phase Modulation). ICPM is a change in carrier phase with a signal level change.
Operating Instructions 2- 26 1720/1721
Warning The following servicing instructions are for use only by qualified personnel. To avoid personnel injury, do not perform any servicing other than that contained in the operating instructions unless you are qualified to do so. Refer to General Safety Summary and Service Safety Summary prior to performing any service.
Service Safety Summary Only qualified personnel should perform service procedures. Read this Service Safety Summary and the General Safety Summary before performing any service procedures. Do Not Service Alone. Do not perform internal service or adjustments of this product unless another person capable of rendering first aid and resuscitation is present. Disconnect Power. To avoid electric shock, switch off the instrument power, then disconnect the power cord from the mains power.
Service Safety Summary S- 2 1720/1721
Installation
Section 3 Installation Packaging The shipping carton and pads provide protection for the instrument during transit, they should be retained in case subsequent shipment becomes necessary. Repackaging instructions can be found in Section 6 (Maintenance) of this manual. Electrical Installation Power Source This instrument is intended to operate from a single-phase power source with one current-carrying conductor at or near earth-ground (the neutral conductor).
Installation J245 Blanking disable J696 Ext sync source Front A3 Main Bd 1 1 J920 Y High gain J921 X High gain J796 Subcarrier ref Figure 3-1: Plug jumper locations. A small arrow on the board, next to the plug jumper, denotes pin 1.
Installation Not Used +Y Input 8 -Y Input 7 6 15 +Y High gain input 14 -Y Input 4 5 GND GND 13 +Y Input 3 GND GND 12 11 2 -Y Input 1 GND GND 10 9 +Y High gain input -Y Input Figure 3-2: Rear panel XY INPUT connector showing pins with their functions. 0 dBm is equal to 1 mW or 2.19 V peak-to-peak in 600Ω. 12 dBm is equal to 15.8 mW or 8.72 V peak-to-peak in 600Ω. Inputs can be driven single-ended by driving either the + or -- X and Y inputs with the opposite polarity inputs grounded.
Installation Ground Ground 5 9 TXD 3 4 RXD 8 2 7 1 6 External strobe out Figure 3-3: View of the 1720/1721 rear panel showing AUXILIARY connector pins with their functions. Table 3- 2: AUXILIARY Connector Pin Assignments Pin # 2-3-4-6 1-5 Use No connection. Ground. 7 External Strobe In for Line Select blanking. 8 RXD (Receive Data) 1730-Series communication to the 1720/1721. 9 TXD (Transmit Data) 1720/1721 return communication to 1730-Series.
Installation 8.250 0.688 6.875 Rear 5.105 0.156 Dia (4) 1.060 6.130 16.180 12.725 Bottom Side Figure 3-4: 1700F00 plain cabinet.
Installation 3- 6 1720/1721
Installation Cabinet Securing Screws Figure 3-6: Cabinet securing screws. The optional 1700F05 side-by-side rack adapter, shown in Figure 3-7, consists of two attached cabinets. It can be used to mount the 1720/1721 and another half-rack width instrument in a standard 19-inch rack.
Installation Handle bracket is attached at this setting when shipped. To mount 1700-Series half-rack instruments even with other Tektronix Television equipment. To mount 1700-Series half-rack instruments, WFM-300A, and 760 even with 528A or 1420-Series. To mount 528A and 1420-Series. Figure 3-8: 1700F05 rack adapter adjustment. If only one section of the rack adapter is used, a 1700F06 Blank Panel can be inserted in the unused section. See Figure 3-9.
Installation Custom Installation For applications such as consoles, the instrument can be mounted with front molding flush or protruding from the console. In both cases, allow approximately 3 inches of rear clearance for BNC and power-cord connections. To mount the 1720/1721 safely, attach it to a shelf strong enough to hold its weight. Install the mounting screws through the four 0.156-inch diameter holes in the bottom of the 1700F00 cabinet. See Figure 3-10.
Installation 3- 10 1720/1721
Theory of Operation
Section 4 Theory of Operation The material in this section is subdivided into general description, which is supported by the main block diagram and simplified block diagrams, and detailed circuit descriptions that use the schematic diagrams as illustrations. A thorough understanding of the instrument starts with a knowledge of how the major circuit blocks fit together, which is then followed up by knowledge of the individual circuit functions.
Theory of Operation other line so that the +V and --V signals can be overlaid for phase matching applications. The regenerated subcarrier, used for demodulation, is applied directly to the B--Y (U) Demodulator and delayed by 90° (quadrature phased) for the R--Y (V) Demodulator. The B--Y (U) Demodulator drives the Horizontal Output Amplifier; the R--Y (V) Demodulator drives the Vertical Amplifier.
Theory of Operation front-panel indicators are driven by the Microprocessor so that they will mirror the current measurement criteria. X Input Y Input To CRT Gain CH A Vertical deflection plates 180° Flip 90° Phase shifter CH B To CRT Horizontal deflection plates Subcarrier regenerator Sync stripper EXT REF Clamp generator Detectors Center dot blanking To CRT Blanking Figure 4-1: Simple block diagram of a 1720/1721 Vectorscope.
Theory of Operation the Quad Phase Detector is delayed by 90°. The chrominance signal is compared to the regenerated subcarrier from the VCXO with the output low-pass filtered and buffered. The Phase Detector output is clamped and supplied to the Error Amplifier, which provides an output voltage to correct the VCXO should it be off frequency. The Quad Phase Detector compares the burst chrominance to 90° phase-shifted subcarrier, with the output low-pass filtered and buffered.
Theory of Operation Circuit Descriptions The following descriptions are divided by diagram number and then further subdivided by logical circuit blocks. The descriptions follow the order of the diagrams in Section 9. Individual diagrams can be folded out and consulted while studying these descriptions.
Theory of Operation junction of a differential amplifier (Q293 and Q292) that drives the Output Amplifier (Q192). The feedback resistor that sets the gain is R293. The External Reference Input Amplifier is nearly identical to the channel inputs and provides a signal to the reference switch. R994 is the input resistor and R992 is the feedback resistor, the combination of which sets the gain to 1. Gain Cell The Gain Cell, whose output is chrominance, consists of U184, U383, Q385, and Q490.
Theory of Operation Burst ref Phase detector Loop filter Burst demod Phase control Subcarrier oscillator VCO Burst amp Burst gate Figure 4-2: Block diagram of the Phase Lock Loop. The heart of the Subcarrier Regenerator is a phase lock loop. See Figure 4-2. The Subcarrier Oscillator (VCXO) is a voltage-controlled oscillator that freeruns near the reference subcarrier frequency.
Theory of Operation Luminance and Chrominance Amplifiers The reference signal is ac-coupled through a tuned circuit, C791 and L791, to drive the Chroma Amplifier, Q794 and Q795. Luminance is removed and in normal operation the chrominance is amplified by about three times. With J796 in the 2 and 3 position (External CW Subcarrier input), the gain is changed to slightly less than one.
Theory of Operation Reference Amplifier. The output of this phase detector is an ac multiplication of the input signals, which occurs only during the time that both of the input signals are present. The average dc output level is proportional to the difference in phase between the inputs. The output is filtered to remove any chrominance and harmonics and drives U640, which is a non-inverting, high-gain operational amplifier.
Theory of Operation PAL Phasing The Subcarrier Regenerator in the 1721 Vectorscope samples alternate lines and locks to every other burst. Alternate line sampling can be defeated by moving W987 to the W986 position, but the +V mode may not be properly phased and there will be more phase jitter. The Quadrature Phase Detector receives every other burst from the Reference Switch.
Theory of Operation DIAGRAM 3 DEMODULATOR Vertical position clamp DEMOD OUT Low pass filter R-Y (V) V Axis switcher CHROMA Bandpass filter Quad phase FSC Low pass filter Syc tip chroma clamp B-Y (U) Horiz position clamp Incoming chrominance is band-pass filtered, clamped at sync tip time, and compared to the phase shifted regenerated subcarrier signal for demodulation. Subcarrier signal is quadrature shifted (90°) before input to the R--Y (V) demodulator.
Theory of Operation U774B (on Diagram 2), which has identified the +V lines (for PAL) in the Subcarrier Regenerator. The flip-flop outputs drive Q552 and Q553. A high output turns on the corresponding transistor to shunt the signal at its collector to ground. This alternately grounds and drives the + and -- carrier inputs on the V Demodulator with subcarrier to demodulate the --V lines 180° away from the +V lines.
Theory of Operation The B--Y Demodulator output is also fed back through R763 to a clamp circuit consisting of U757 and Q761. U757 is an operational transconductance amplifier used in a sample-and-hold circuit. The demodulated B--Y chrominance drives the negative input (pin 2), while a voltage, controlled by the Vector Horizontal Position control (R653), is reference level to the positive input (pin 3).
Theory of Operation XY Input Amps U942 is a Quad Operational Amplifier. U942A and B are Balanced Differential Input Amplifiers, intended for audio use. In a 600Ω system, R846 and R948 can be adjusted to normalize signals from 0 dBm to +12 dBm (2 V p-to-p to 9 V p-to-p). The input impedance is greater than 20 kΩ to ground. J920 and J921 can be installed so that the plus inputs of the X and Y amplifiers are connected to the high gain X and Y ports.
Theory of Operation DIAGRAM 5 MICROPROCESSOR Auxiliary control in Buffer Readout drive Address Demux Microprocessor I/O Data switch Switch control Front panel controls NOVRAM LED Drive Operation of the 1720/1721 is controlled by the Microprocessor. It controls switching operation by either polling the front-panel switches, or in response to stored/recalled front-panel configurations (Auxiliary Input from a companion 1730-Series).
Theory of Operation control lines (75%, 100%, and Variable) for instrument switching functions. Other switching control lines are output directly from U613, ports 1 and 3. See Table 4--1.
Theory of Operation 3. In Auxiliary, when a Store or Recall is requested from the companion 1730-Series. U505 is the Power Down Detection circuit. It detects the loss of instrument power in time for the NOVRAM (U405) to execute a save operation. When the +5 V supply drops a few hundred millivolts, pin 7 is pulled low, which causes U405 to Store its current status.
Theory of Operation In Line Select mode (which requires an external blanking pulse, input through the Auxiliary connector, from a 1730-Series or other source) the intensity setting has to change to brighten up the line(s). This is accomplished by increasing the current through the current source (Q342). U341A is an open collector dual comparator that goes low when the Line Select Blanking occurs, which allows current in R241 to add to the current in Q342, the current source.
Theory of Operation DIAGRAM 7 LOW VOLTAGE POWER SUPPLY AC Line Isolated secondary Line rectifier and filter Voltage snubber Kick starter Pulse width modulator Base drive and switching transistr Supply voltage Current limit Opto isolator Error +5V Isolated secondary The Low Voltage Power Supply converts the mains line voltage (90--250 VAC) to supply the power requirements of the instrument. The voltages supplied by the Low Voltage Power Supply are +40 V, 15 V, and +5 V.
Theory of Operation Pulse Width Modulator Simplified pulse width modulator Oscillator Switcher mosfet Q9 +2.5V R83 10.0K From peak detector 2 + -- 2R -+ R 1 R84 24.9K R79 49.9K Latch 6 3 R101 49.9 R87 22.1 R96 0.51 U5 is a current-mode pulse width modulator (PWM). A current-mode PWM uses two feedback loops. The inner current-feedback loop directly controls the switcher mosfet peak current. The outer voltage-feedback loop programs the inner loop peak current trip point.
Theory of Operation Error Amplifier The Error Amplifier regulates the +5 V output by feeding an error signal to the Pulse Width Modulator. VR1 is a 2.5 V shunt regulator containing an op-amp and a voltage reference. The +5 V is divided by R69 and R70 to provide 2.5 V to VR1, with fine adjustment provided by R99. C40 and R71 determine the gain and frequency response of VR1. VR4 controls overshoot of the +5 V at power up. R98 and CR26 provide a minimum operating current for VR1. R68 decouples C39 from VR1.
Theory of Operation DIAGRAM 8 HIGH VOLTAGE POWER SUPPLY 4X Multiplier CRT OSC Error Focus <6> Z-Axis <6> The High Voltage Power Supply generates the heater, cathode, control grid, focus anode, and post accelerating potentials required to display the outputs of the Vertical and Horizontal Output Amplifiers. HV Osc and Error Amp The High Voltage Power Supply is generated by a sine-wave oscillator and step-up transformer.
Theory of Operation Q1 and Q2 form an operational amplifier that sets the voltage at the bottom of the focus divider. The front-panel FOCUS pot determines the voltage at the bottom of the focus divider. The Center Focus control, R11, is set for optimum beam focus, as viewed on the crt, with the front-panel FOCUS control set to mid range.
Theory of Operation pull-down transistor. C6 speeds up the amplifier by coupling ac signals to the base of Q3. CR2 and R41 protect the amplifier during crt arcing. The pinout for the CRT is shown in Figure 4-3. Pin Description 1.....................................Filament (f) 2.....................................Cathode (k) 3.......................................GRID (g1) 4...................................FOCUS (g3) 5.....................................ASTIG (g4) 6...................................
Checks and Adjustments
Section 5 Checks and Adjustments Checks and adjustments are two separate procedures. The first, a Performance Check, is used to determine compliance with the Performance Requirements in the Specification. The Specification in Section 1 contains numerical references to the procedure. The second procedure is the Adjustment Procedure, which provides adjustment instructions for the instrument that will return it to operation within the written Specification (Section 1).
Checks and Adjustments PAL TEKTRONIX 1411 with Option AA and Option AB (modified SPG12 and TSG11) and TSG13. PAL-M TEKTRONIX 1412 with Option AA and Option AB (modified SPG22 and TSG21) and TSG23. The 1410, 1411, and 1412 Option AA are mainframes with modified SPG2, 12, and 22 Sync Generators with the added features of: Variable Subcarrier Frequency (±20 Hz, ±50 Hz for the 1410; ±5 Hz, ±10 Hz for the 1411 and 1412), Variable Burst amplitude, Variable Sync amplitude, and SCH unlock. NOTE.
Checks and Adjustments For example: A TEKTRONIX TM506 Power Module. 7. Variable Autotransformer For example: General Radio Metered Auto Transformer W10MT3W. If 220 Volt operation must be checked, a conversion transformer or appropriate 220 V autotransformer is needed. 8. Spectrum Analyzer with Tracking Generator Bandwidth ² 10 MHz and sensitivity to 50 dB. For example: TEKTRONIX 2712 Opt 04 Auxiliary Equipment 9. RF Bridge Range, at least 46 dB loss sensitivity, 50 kHz to 10 MHz.
Checks and Adjustments 14. Dual Input Coupler Matched BNC cable-T for making phase comparisons between two inputs. Matched length of the two arms within ±0.1 inch. For example: Tektronix Part No. 067--0525--02. 15. Precision 50Ω Coaxial Cable Tektronix Part No. 012--0482--00 (used with the TEKTRONIX SG503). 16. 50Ω to 75Ω Minimum Loss Attenuator Tektronix Part No. 011--0057--00. 17. Female to Female BNC adapter Tektronix Part No. 103--0028--00 18.
Checks and Adjustments Performance Check Procedure Short-Form Reference The short-form reference table is intended for those who are familiar with the complete Performance Check procedure. Step and page numbers provide easy cross-reference to the long-form procedure on the following pages. Table 5- 1: Performance Check Procedure Short-Form Reference Step # Step Name Step Requirement Page # 1 Preliminary Setup Initial equipment connections and control settings.
Checks and Adjustments Performance Check Procedure 1. Preliminary Setup a. Connect the variable autotransformer to the AC power connector. Turn Power On and set the autotransformer for the voltage shown by the rear-panel Line Voltage Selector switch. b. Connect a composite color bar signal with 100% Peak White Bar and 75% amplitude color bars through the CH-B INPUT and terminate the opposite side of the loop-through with a 75Ω terminator. c.
Checks and Adjustments 1720/1721 (rear) 1410-- Series (rear) Black burst 75Ω Termination Figure 5-2: Loop-through connection of black burst signal to both EXT REF and CH-B. b. Use the 1720/1721 PHASE control to place the burst vector tip(s) on the graticule target(s). c. Remove the 75Ω terminator from CH-B. d. CHECK -- for stable display in both EXT and INT reference modes. e. Triple terminate CH-B, using three 75Ω terminators. f. CHECK -- for a stable display in both EXT and INT reference modes. g.
Checks and Adjustments Figure 5-3: Using the vector graticule - 3 dB markings to measure bandwidth. Amplitude is set to the compass rose at the center frequency, and then as the frequency is increased or decreased the total deflection reduces to the openings, at the shaded inner circle, on the axes lines. e. CHECK -- that the frequency readout on the Sine Wave Generator is between 2.98 to 3.18 MHz NTSC and PAL-M (3.83 to 4.03 PAL). f. Repeat parts c. and d. for the horizontal graticule axis. g.
Checks and Adjustments c. CHECK -- that all of the vectors fall within ±1.25° and ±1.25 IRE (NTSC and PAL-M), or ±1.25° and ±2.5% (PAL) of the target centers. These specifications represent one-half the dimension from the center cross of a vector target to the edge of the small inner box. Perform steps d. and e. for the 1721 only: d. Select the +V VECT MODE. e. CHECK -- that the Burst vectors can be overlaid with the PHASE control. 6.
Checks and Adjustments 5- 10 1720/1721
Checks and Adjustments staircase) to the burst cross on the horizontal graticule axis. Use the small dot on the --U axis for PAL and PAL-M. b. Turn on the VARIABLE switch and use the VARIABLE control to place dots at the outer graticule circle. c. CHECK -- that dots are overlaid to ±1° in phase, and ±1% in gain. 9. Check Chrominance Vector Clamp Performance REQUIREMENT -- Clamp stability: 1/64” (0.4 mm) or less center dot movement as the PHASE control is rotated throughout its range.
Checks and Adjustments g. Disconnect the Black Burst signal and the terminators from the 1720/1721. 11. Return Loss Requirement -- Video Inputs: ≥40 dB to 6 MHz. Power on or off.. NOTE. Return Loss Check: The Return Loss Check needs to be done only if repairs have been made on the Input circuitry. a. Connect a precision 50Ω cable from the spectrum analyzer RF Input to the RF Output on the RF Bridge. b. Connect a precision 50Ω cable from the spectrum analyzer TG Output to the RF Input on the RF Bridge. c.
Checks and Adjustments o. Remove the precision high-frequency terminator from the RF Bridge. p. Connect the male-to-male bnc adapter to the Device Under Test connector on the RF Bridge. q. Connect the Device Under Test connector on the RF Bridge to the 1720--Series CH-A INPUT. Terminate the CH-A loop-through with the same precision high-frequency terminator used in step o. r. Select CH-A INPUT. s. Check -- that the Reference Level Readout on the spectrum analyzer is ≥40 dBm, with the instrument on and off.
Checks and Adjustments Not used +Y INPUT 8 7 -Y INPUT 6 5 GND GND 15 14 +Y HIGH GAIN INPUT 13 -Y INPUT +X INPUT 4 3 GND GND 12 11 -X INPUT 2 1 GND GND 10 +X HIGH GAIN INPUT 9 -X INPUT Figure 5-5: Rear-panel XY INPUT connector showing inputs. g. CHECK -- that either end of the trace can be moved >1° (one-half minor division on the compass rose) either direction from horizontal. h. Set ROTATE so that the trace is on the horizontal axis. 13.
Checks and Adjustments Minimum opening Figure 5-6: Audio frequency XY display. 14. Check XY Frequency Response REQUIREMENT -- The --3 dB point at 500 kHz or greater in standard mode; 100 kHz or more in High Gain mode. a. Connect the Function Generator, using the red alligator clip, to pin 3 (+X) of the 1720/1721 rear-panel XY INPUT connector. Leave the black alligator clip connected to pins 1 and 5. See Figure 5-5. b.
Checks and Adjustments Perform parts i. through p. only if internal jumpers J920 and J921 (Main board) are set to High Gain mode. i. Connect the Function Generator output to pin 11 (+X HIGH GAIN) and ground pin 9 (+X) of the 1720/1721 rear-panel XY INPUT connector. See Figure 5-5. j. Set the Function Generator frequency to approximately 10 kHz and adjust its amplitude for a display equal to the width of the graticule compass rose. k. Set the Function Generator to 100 kHz. l.
Checks and Adjustments Adjustment Procedure This procedure is divided into two parts. The first, a short form, is an outline of the full procedure. The full procedure is more detailed and is intended to lead a technician through each step. The short form can be used as a short cut for those familiar with the instrument calibration or an index of steps in the longer form. Figure 5-7 shows the adjustment locations. (Note that R453 +V Overlay is only in the PAL and PAL-M, 1721 Vectorscopes.
Checks and Adjustments 1720/1721 (rear) 1410-- Series (rear) 75Ω Terminator Color bar Black burst 75Ω Termination Figure 5-8: Starting connections for the adjustment procedure. Connect the Function Generator to the 1720/1721 XY INPUT. See Figure 5-1 for a diagram of how to hook up the 15-pin D-type connector to calibrate the 1720/1721 Vectorscope. Set the Function Generator frequency to 50 kHz.
Checks and Adjustments Table 5- 2: Adjustment Procedure Short-Form Reference Step # 1720/1721 Step Name Adjusted Components Page # 1 Adjust +5 V R99 5-- 20 2 Adjust CRT Bias R58 5-- 20 3 Adjust Geometry, Focus and Astigmatism R45, R11, R49 5-- 20 4 Adjust Trace Rotation and Orthogonality R578 5-- 20 5 Adjust On- Board Regulated Power Supplies R259, R267 5-- 21 6 Adjust Lock-In Phase C235 5-- 22 7 Adjust Center Dot Overlay and Vector Position R355, R653 5-- 22 8 Adjust Phas
Checks and Adjustments Long-Form Adjustment Procedure See the Front-Panel Presets and Signal Connections in the Adjustment Procedure introduction for the correct settings of the front-panel controls and the correct signal connections for this procedure. Figure 5-7 shows the adjustment locations. 1. Adjust +5 V a. Connect the DMM negative lead to TP1 (GND) and the positive lead to W1 (+5V). b. ADJUST -- R99 (+5V ADJ) for +5.0 V 0.5V. 2. Adjust CRT Bias a. Turn the intensity control fully counterclockwise.
Checks and Adjustments g. Adjust R571 (Orthogonality) on the Main board for a straight vertical line parallel to the Y axis. h. Disconnect the Function Generator from the 1720/1721. 5. Adjust On--Board Regulated Power Supplies a. Connect the voltmeter ground lead to one of the rear-panel ground lugs and the active lead to the --11.8 V test point. See Figure 5-9. A3 Main Bd Front +11.8 V Test point - 11.8 V Test point U164 R259 - 11.8 V ADJUST 1720/1721 U172 R267 +11.
Checks and Adjustments c. Change the Television Signal Generator’s subcarrier frequency by --50 Hz for NTSC and PAL-M (--10 Hz for PAL). d. Connect the voltmeter ground lead to one of the rear-panel ground lugs, and the active lead to pin 1 of U734. e. Adjust C235 for a locked display and a voltmeter reading of 0.5 V for NTSC and PAL-M (1 V for PAL). f. Change the generator’s subcarrier frequency by +50 Hz for NTSC and PAL-M (+10 Hz for PAL) and check for a locked display. g.
Checks and Adjustments b. Connect the Function Generator red clip lead to pin 7 ( +Y) on the rear-panel X Y INPUT connector. Connect the Function Generator black clip lead to pins 1 (--X) and 5 (--Y). c. Adjust R846 (Y Gain) for a Y axis display equal to the vertical distance between the centers of the dB boxes. d. Move the Function Generator red clip lead from pin 7 to pin 3 (+X) on the rear-panel X Y INPUT. e.
Checks and Adjustments b. Hold the REF switch in until the TEST indicator lights. c. Set the front-panel GAIN CAL to midrange. d. Position the center dot directly under the graticule center mark (+). e. Adjust C453 (Quad Phase) and R453 (+V Bal) for the best overlay of the test circles. 13. Adjust R--Y and B--Y Gains a. Check to see that the center dot is directly under the graticule center mark (+). b. Adjust R460 (R--Y Gain) to place the outer circle directly over the RED and CYAN (R and CY) targets. c.
Checks and Adjustments 15. Adjust Line Select Focus With a 1730-Series Waveform Monitor: a. Connect an Auxiliary cable between the 1720/1721 and a 1730-Series of the same color standard. b. loop-through connect the color bar signal to both the waveform monitor and the 1720/1721. c. Set the 1730-Series Waveform Monitor for line select and display one line from the active part of the field (after the vertical interval). d. Push the 1720/1721 AUXILIARY button. e.
Checks and Adjustments 5- 26 1720/1721
Maintenance
Section 6 Maintenance This section contains instructions for preventive maintenance, general troubleshooting, Serial Port and LED Driver diagnostics, and corrective maintenance. If the instrument does not function properly, troubleshooting and corrective measures should be taken immediately to circumvent additional problems. Preventive Maintenance Preventive maintenance consists of cleaning, visual inspection, performance checking, and, if needed, readjustment.
Maintenance (high-velocity air can damage some parts). Hardened dirt or grease may be removed with a cotton-tipped applicator dampened with a solution of mild detergent and water. Abrasive cleaners should not be used. If the circuit board assemblies must be removed for cleaning, follow the instructions for removal/replacement under the heading of Corrective Maintenance. After cleaning, allow the interior to thoroughly dry before applying power to the instrument. CAUTION.
Maintenance Table 6- 1: (Cont.)Static Susceptibility Relative Susceptibility Levels 7 Voltage LINEAR CIRCUITS 400 to 1000 V est. 8 LOW POWER SCHOTTKY TTL 900 V 9 TTL 1200 V Observe the following precautions to avoid damage: 1. Minimize handling of static-sensitive components. 2. Transport and store static-sensitive components or assemblies in their original containers, on a metal rail, or on conductive foam. Label any package that contains static-sensitive components or assemblies. 3.
Maintenance Troubleshooting The material contained here is general and is not intended to cover specific cases. Note that the manual itself is considered a troubleshooting aid, and as such a brief discussion of its content is in order. The procedural information that appears as General Troubleshooting Techniques should be familiar to most technicians; however, a quick review may save some time and reduce “wheel spinning.
Maintenance A1 Power Supply Board A3 Main Board A2 Front Panel Board Figure 6-1: Circuit board assembly locations Parts Lists There are two separate parts lists in this manual. The Replaceable Electrical Parts list is in Section 8, which precedes the schematic diagrams and circuit board illustrations. The Replaceable Mechanical Parts list (Section 10), accompanied by exploded view drawings, follows the schematic diagrams and circuit board illustrations. Replaceable Electrical Parts.
Maintenance numbers that identify terminal connectors; numerals are used from 2 up. A triangular key symbol is used to identify pin 1 on the circuit board and the connector to assist in aligning the connector with correct square pins. Figure 6-2 shows the numbering scheme (and the triangular marking) on the connector and the marking on the etched circuit board. A pin replacement kit including necessary tools, instructions, and replacement pins is available from Tektronix, Inc.
Maintenance Instructions in Section 2), and by being sure that a malfunction has not occurred down stream from the vectorscope. 2. Determine and evaluate all trouble symptoms. This is accomplished by isolating the problem to a general area such as an assembly. The block diagram is a valuable aid in signal tracing and circuit isolation. CAUTION. Probes and Meter Leads: Use extreme care when probing with meter leads or probes, because of the high component density and limited access within the instrument.
Maintenance Specific Troubleshooting Procedures Two areas of the the 1720/1721 instrument require specific troubleshooting methods. The power supply can not be worked on safely without using an Isolation Transformer and following a specific troubleshooting procedure. The Serial Port (Auxiliary Input) and the LED Driver circuits have specific diagnostic routines. These should be followed to isolate problems quickly.
Maintenance determining which section of the power supply the problem is in. Apply ac power and turn on the power supply. From Table 6--2, determine which symptom the power supply exhibits and refer to the corresponding procedure.
Maintenance NOTE. Low Volts Supply Power Connection: The Low Volts power supply troubleshooting is performed without applying ac power. b. Disconnect ac power from the instrument. Disconnect the instrument from the Power Supply by removing the jumper from J4. c. Use the digital multimeter to measure the voltage between TP2 and the tab (drain) of Q9. Check that the voltage is near 0 V. CAUTION. Dangerous Voltages: Do not proceed until the drain of Q9 is near 0 V.
Maintenance c. Connect the positive output from the 20 VDC Power Supply to TP1. Connect the negative output to W3 (--15 V). The circuit should draw less than 20 mA. Excessive current draw can be caused by CR12. d. Connect the negative output from the 5 VDC Power Supply to TP1. Connect the positive output to W1 (+5 V). The circuit should draw less than 20 mA. Excessive current draw can be caused by CR13 or Q1 and Q2 (High Volts power supply). 4. Control Circuit Check a.
Maintenance b. Connect the negative output of another variable DC power supply to TP1. Connect the positive output to W4 (+15 V). Set the variable power supply to 20 VDC. c. Connect the digital multimeter between TP1 and the cathode of CR15. d. Set the variable DC power supply connected to W1 (+5 V) to 4.8 V. The cathode of CR15 should be approximately 20 V. e. Set the variable DC power supply connected to W1 (+5 V) to 5.2 V. The cathode of CR15 should be approximately 2 V. f.
Maintenance 3. Z-Axis Amplifier Check a. Unsolder and lift one end of R8. b. Power up the power supply. c. Using the digital multimeter, measure the voltage between TP1 and the collector of Q4. It should be approximately +10 V. d. Short together the base and emitter of Q5. The collector of Q4 should be approximately +100 V. e. Reconnect the lifted end of R8. 4. Grid Drive Check a. Turn off the power supply. Use the diode check on the digital multimeter to test CR1, CR2, CR3, CR5, and CR6 for shorts. b.
Maintenance 6. CRT Voltage Check NOTE. High Voltage Probe: This check requires a high voltage probe having an input resistance of 1 GΩ or more. a. Connect the high voltage probe ground to TP1. b. Load the Low Volts supply with the instrument, or with a 20Ω, 2 watt resistor loading the 5 V supply. c. Power up the power supply. d. Use the high voltage probe to measure the voltage at the anode of CR4. It should be approximately --2530 V. e. Measure the voltage at the anode end of CR3.
Maintenance 5. Turn off POWER. This ends the Diagnostic Procedure. When the 1720/1721 is powered up again it will be operating in the normal vectorscope configuration. Corrective Maintenance NOTE. Solder: A 2% RMA flux content solder is recommended for making repairs in this instrument. Cleaning of rosin residue is not recommended. Most cleaning solvents tend to reactivate the rosin and spread it under components where it may cause corrosion under humid conditions.
Maintenance Mechanical Disassembly/Assembly The instructions contained here are for disassembly. Re-assembly is performed by reversing the order of the steps used to disassemble the instrument. WARNING. Unplug Power Cord: Before attempting any disassembly of the instrument be sure to disconnect the power cord. CAUTION. Rear Panel Screws: Do not re-insert screws in the rear panel when the instrument is removed from the cabinet. NOTE.
Maintenance Remove these screws in order to remove the bezel Figure 6-3: Screws that need to be removed to remove the bezel. Graticule Light Removal and Replacement For graticule light removal and replacement, tweezers with curved, serrated tips are recommended. For example: Miltex PL312, 6--100 (equivalent to PL312), or PL317 (longer than PL312). CAUTION. Bulb Removal: Needle-nosed pliers are not recommended. Replacement bulbs are supplied with this instrument as Standard Accessories.
Maintenance 3. To install a bulb, hold it with the tweezers as described in step 2, position it in front of the socket and push the bulb with your finger until it snaps into place. 4. Replace the bezel. CRT Removal Removal of the CRT 1. Remove the bezel. WARNING. The CRT may retain a dangerous charge. Ground the conductor of the anode to discharge the CRT. Do not allow the conductor to touch your body or any circuitry. 2.
Maintenance WARNING. The CRT may retain a dangerous charge. Ground the the anode connector to discharge the CRT. Do not allow the conductor to touch your body or any circuitry. 3. Use a screwdriver to ground the anode connector on the CRT to the chassis. 4. Slide the CRT into the instrument, guiding the rubber manchet on the end of the shield into the rear CRT support. 5. Align the socket on the A10 CRT Socket board with the pins and key on the CRT.
Maintenance Remove these five (5) screws to remove the rear panel. VECTORSCOPE DEMOD OUT AUXILIARY CONTROL IN CH-- A INPUT CH-- B X Y INPUT EXT REF 75 OHM LOOP-- THROUGH Figure 6-4: Screws that need to be removed to remove the rear panel Removing the Front Panel Circuit Board 1. Remove the blue multiwire connector from J154. 2. Remove the two screws holding the board in place. See Figure 6-5 for locations. 3. Remove the board by slipping it through the front-panel opening. 4.
Maintenance To remove front panel assembly To separate board from the front panel To remove front panel assembly Figure 6-5: Screws that hold the Front Panel circuit board (A2) in place. Removing the Main Board 1. Remove the plugs from the following connectors: J216 to the Front Panel board, J546 on the Power Supply board, the plug on the Phase Shifter (Assembly A4), and J225 on the Main board (the trace rotation leads to the crt). 2.
Maintenance A3 Main Bd J153 Front J216 J933 Figure 6-6: Screws holding the main circuit board (A3) in place. 5. Remove the board by sliding it toward the rear panel until the toe of the board clears the front, then lift out. 6. To replace the Main board, lay the board flat and slide it back into place. 7. To complete the replacement of the board, reverse the rest of the steps. Removing the Power Supply Board 1.
Maintenance 8. To replace the board, reverse this procedure. Ground shield A1 Pwr Supply Bd J3 Front J1 J2 J4 Figure 6-7: Screws holding the Power Supply circuit board (A1) in place. Repackaging Identification Tag If the instrument is to be shipped to a Tektronix Service Center for service or repair, attach a tag to the instrument showing: 1. Owner (with complete address) and the name of the person at your firm that can be contacted. 2.
Maintenance 6- 24 1720/1721
Options
Section 7 Options This section describes instrument options and customer-installable Field Upgrade Kits for the 1720/1721. Options CRT Options The standard instrument is shipped with a P31 (green) phosphor crt installed. If Option 74 is ordered the instrument is shipped with a P4 (white) phosphor crt installed. The Option 74 crt part number is given at the end of the Replaceable Electrical Parts list. Power Cord Options Any of the following power cord options can be ordered for the 1720/1721.
Options the installation of these instruments. Only a brief description is provided here, for more information contact a Tektronix field office or distributor. Dimensional cabinet drawings are located in Section 3 (Installation) Plain Cabinet (1700F00) Carrying Case (1700F02) Side-by-Side Rack Adapter (1700F05) This is a plain, silver-grey cabinet that is designed for permanent mounting.
Replaceable Electrical Parts
Replaceable Electrical Parts This section contains a list of the components that are replaceable for the 1720/1721. Use this list to identify and order replacement parts. There is a separate Replaceable Electrical Parts list for each instrument. Parts Ordering Information Replacement parts are available from or through your local Tektronix, Inc., Field Office or representative.
Replaceable Electrical Parts List of Assemblies A list of assemblies can be found at the beginning of the electrical parts list. The assemblies are listed in numerical order. When the complete component number of a part is known, this list will identify the assembly in which the part is located. Column Descriptions Component No. (Column 1) The component circuit number appears on the diagrams and circuit board illustrations, located in the diagrams section.
Replaceable Electrical Parts The mechanical subparts are shown as *ATTACHED PARTS* / *END ATTACHED PARTS* or *MOUNTING PARTS* / *END MOUNTING PARTS* in column five (5). Mfr. Code (Column 6) Mfr. Part No. (Column 7) 1720/1721 Indicates the code number of the actual manufacturer of the part. (Code to name and address cross reference can be found immediately after this page.) Indicates actual manufacturer’s part number.
Replaceable Electrical Parts Cross Index - Mfr. Code Number To Manufacturer Mfr. code.
Replaceable Electrical Parts Mfr. code. Manufacturer Address City, state, zip code 33096 34361 COLORADO CRYSTAL CORP OMRON ELECTRONICS INC.
Replaceable Electrical Parts Mfr. code.
Replaceable Electrical Parts Replaceable Electrical Parts Component number Tektronix part number Serial / Assembly number Effective Discontinued A1 A1 A1 671-- 2890-- 10 671-- 2890-- 11 671-- 2890-- 12 B050000 B060000 B066637 B059999 B066636 A1 A1 A1 671-- 2890-- 10 671-- 2890-- 11 671-- 2890-- 12 B050000 B060000 B066738 B059999 B066737 A2 A2 670-- 9384-- 00 670-- 9384-- 01 B050000 B060000 B059999 A2 A2 670-- 9528-- 00 670-- 9528-- 01 B050000 B060000 B059999 A3 A3 A3 A3 672-- 1227-- 07
Replaceable Electrical Parts Component number Tektronix part number A1C3 A1C4 A1C5 A1C6 A1C7 283-- 0261-- 00 283-- 0261-- 00 285-- 1341-- 01 281-- 0771-- 00 285-- 1470-- 00 A1C8 A1C9 A1C10 A1C11 A1C12 A1C13 A1C14 A1C15 A1C16 283-- 0261-- 00 283-- 0261-- 00 281-- 0563-- 00 283-- 0021-- 00 281-- 0707-- 00 281-- 0707-- 00 281-- 0707-- 00 285-- 1341-- 01 290-- 1311-- 00 A1C17 A1C18 A1C19 285-- 1341-- 01 281-- 0775-- 01 290-- 1310-- 00 A1C20 A1C21 A1C22 A1C23 281-- 0707-- 00 281-- 0707-- 00 281-- 0563-
Replaceable Electrical Parts Component number Tektronix part number A1C44 A1C45 A1C46 A1C47 A1C47 A1C48 A1C49 A1C50 A1C51 A1C52 A1C53 A1C54 A1C56 A1C57 A1C58 A1C59 A1C60 A1C61 A1C65 A1C66 285-- 1331-- 00 281-- 0563-- 00 283-- 0005-- 03 281-- 0563-- 00 283-- 0059-- 00 281-- 0809-- 00 281-- 0775-- 01 281-- 0563-- 00 281-- 0773-- 00 281-- 0773-- 00 285-- 1437-- 00 290-- 1275-- 00 285-- 1246-- 00 285-- 1222-- 00 281-- 0809-- 00 281-- 0775-- 01 281-- 0775-- 01 281-- 0768-- 00 285-- 1301-- 01 290-- 1311-- 00
Replaceable Electrical Parts Component number A1DS4 A1F1 Tektronix part number 150-- 0050-- 00 159-- 0021-- 00 200-- 2264-- 00 204-- 0906-- 00 A1J1 131-- 5338-- 00 A1J2 131-- 4794-- 00 A1J3 A1J4 A1J6 A1L1 131-- 5337-- 00 131-- 3392-- 00 119-- 1946-- 00 108-- 1412-- 00 A1L2 108-- 1412-- 00 A1L3 108-- 1412-- 00 A1L4 108-- 0205-- 00 A1Q1 A1Q2 A1Q3 A1Q4 A1Q5 A1Q6 151-- 0749-- 00 151-- 0190-- 00 151-- 0350-- 03 151-- 0347-- 02 151-- 0350-- 03 151-- 0476-- 00 214-- 3848-- 00 A1Q7 A1Q8 A1Q9 151--
Replaceable Electrical Parts Component number Tektronix part number A1R25 A1R26 A1R27 A1R28 A1R29 A1R30 A1R31 A1R32 A1R33 A1R34 A1R35 A1R36 A1R37 A1R38 A1R39 A1R40 A1R41 A1R42 A1R43 A1R44 A1R45 A1R46 A1R47 A1R48 A1R49 A1R49 322-- 3097-- 00 322-- 3452-- 00 322-- 3300-- 02 322-- 3344-- 00 315-- 0470-- 03 315-- 0103-- 03 322-- 3385-- 00 322-- 3452-- 00 322-- 3300-- 02 322-- 3222-- 00 322-- 3162-- 00 322-- 3222-- 00 322-- 3034-- 00 315-- 0226-- 01 315-- 0471-- 03 315-- 0103-- 03 322-- 3121-- 00 322-- 3402--
Replaceable Electrical Parts Component number Tektronix part number Serial / Assembly number Effective Discontinued A1R78 A1R79 A1R80 A1R81 A1R82 A1R83 A1R84 A1R85 A1R86 A1R87 A1R88 A1R89 A1R90 A1R91 A1R92 A1R93 A1R94 A1R95 A1R96 A1R97 A1R98 A1R99 A1R101 A1R102 A1R103 A1T1 322-- 3248-- 00 322-- 3356-- 00 322-- 3222-- 00 322-- 3121-- 00 322-- 3260-- 00 322-- 3289-- 07 322-- 3315-- 00 322-- 3385-- 00 308-- 0793-- 00 322-- 3034-- 00 322-- 3222-- 00 307-- 0746-- 00 305-- 0242-- 00 306-- 0104-- 00 306-- 010
Replaceable Electrical Parts Component number A2 Tektronix part number 670-- 9528-- 01 Serial / Assembly number Effective Discontinued B060000 352-- 0779-- 00 A2DS116 150-- 1109-- 00 A2DS118 150-- 1109-- 00 A2DS132 150-- 1109-- 00 A2DS133 150-- 1109-- 00 A2DS134 150-- 1109-- 00 A2DS146 150-- 1109-- 00 A2DS147 150-- 1109-- 00 A2DS227 A2DS247 150-- 1138-- 00 150-- 1109-- 00 A2DS249 150-- 1109-- 00 A2DS321 150-- 1109-- 00 A2DS323 150-- 1109-- 00 A2DS521 150-- 1109-- 00 A2J303 175--
Replaceable Electrical Parts Component number A2R412 Tektronix part number Serial / Assembly number Effective Discontinued 311-- 2540-- 00 670-- 9528-- 01 366-- 1701-- 01 214-- 4725-- 00 670-- 9384-- 01 214-- 4725-- 00 670-- 9528-- 01 A2R429 A2R429 311-- 2287-- 00 311-- 2540-- 00 670-- 9384-- 00 670-- 9384-- 01 670-- 9384-- 00 A2R429 A2R429 311-- 2287-- 00 311-- 2540-- 00 670-- 9528-- 00 670-- 9528-- 01 670-- 9528-- 00 366-- 1701-- 01 214-- 4725-- 00 670-- 9384-- 01 214-- 4725-- 00 670-
Replaceable Electrical Parts Component number A2S243 Tektronix part number Serial / Assembly number Effective Discontinued 260-- 2300-- 00 366-- 0616-- 00 A2S317 260-- 2300-- 00 366-- 0616-- 00 A2S518 260-- 2300-- 00 366-- 0616-- 00 A3 A3 A3 A3 672-- 1227-- 07 672-- 1227-- 09 672-- 1227-- 10 672-- 1227-- 12 B050000 B060000 B065975 B068301 B059999 B065974 B068300 A3 A3 A3 A3 672-- 1228-- 08 672-- 1228-- 09 672-- 1228-- 10 672-- 1228-- 12 B050000 B060000 B066273 B077737 B059999 B066272 B07773
Replaceable Electrical Parts Component number Tektronix part number A3C198 A3C199 281-- 0302-- 00 290-- 0848-- 00 A3C211 A3C211 A3C211 A3C211 A3C211 A3C211 A3C211 A3C211 A3C213 A3C213 A3C213 A3C213 A3C213 A3C213 A3C213 A3C213 A3C219 A3C219 A3C219 A3C219 A3C219 A3C219 A3C219 A3C219 A3C222 A3C223 A3C234 A3C235 A3C236 A3C237 A3C239 A3C246 A3C250 A3C251 A3C256 A3C257 A3C278 A3C290 A3C328 A3C333 A3C336 A3C336 A3C336 A3C337 A3C337 A3C337 A3C339 A3C344 A3C346 A3C347 A3C348 A3C349 281-- 0775-- 01 283-- 0177--
Replaceable Electrical Parts Component number Tektronix part number A3C349 A3C349 A3C352 A3C353 A3C353 A3C353 A3C356 A3C361 A3C362 A3C363 A3C368 A3C370 A3C372 A3C374 A3C376 A3C380 A3C381 A3C388 A3C389 A3C394 A3C405 A3C405 A3C405 A3C405 A3C405 A3C405 A3C405 A3C405 A3C428 A3C432 A3C437 A3C437 A3C437 A3C438 A3C446 A3C448 A3C451 A3C451 A3C451 A3C452 A3C453 290-- 0943-- 02 290-- 0943-- 02 281-- 0775-- 01 283-- 0638-- 00 283-- 0674-- 00 283-- 0638-- 00 281-- 0773-- 00 281-- 0775-- 01 281-- 0775-- 01 290-- 094
Replaceable Electrical Parts Component number Tektronix part number A3C512 A3C512 A3C512 A3C512 A3C513 A3C520 A3C523 A3C532 A3C534 A3C536 A3C540 A3C543 A3C548 A3C548 A3C548 A3C554 A3C555 A3C562 A3C576 A3C591 A3C592 A3C593 A3C596 A3C616 281-- 0775-- 01 283-- 0177-- 00 281-- 0775-- 01 283-- 0177-- 00 290-- 0948-- 00 281-- 0775-- 01 281-- 0775-- 01 281-- 0826-- 00 283-- 0628-- 01 283-- 0628-- 01 283-- 0645-- 01 283-- 0645-- 01 283-- 0796-- 00 283-- 0639-- 00 283-- 0796-- 00 281-- 0775-- 01 281-- 0775-- 01
Replaceable Electrical Parts Component number Tektronix part number A3C761 A3C764 A3C769 A3C776 281-- 0775-- 01 290-- 0943-- 02 290-- 0943-- 02 281-- 0862-- 00 A3C777 A3C781 A3C787 A3C788 A3C791 A3C791 A3C791 A3C805 A3C806 A3C824 A3C826 A3C832 A3C836 A3C838 A3C842 A3C844 A3C854 A3C855 A3C856 A3C872 A3C873 A3C881 A3C885 A3C898 281-- 0765-- 00 281-- 0775-- 01 281-- 0775-- 01 281-- 0775-- 01 283-- 0638-- 00 283-- 0674-- 00 283-- 0638-- 00 281-- 0819-- 00 281-- 0819-- 00 283-- 0788-- 01 283-- 0796-- 01 28
Replaceable Electrical Parts Component number Tektronix part number A3CR167 A3CR235 A3CR236 A3CR242 A3CR248 A3CR297 A3CR357 A3CR358 A3CR428 A3CR438 A3CR474 A3CR476 A3CR484 A3CR486 A3CR496 A3CR518 A3CR519 A3CR522 A3CR536 A3CR540 A3CR632 A3CR639 A3CR680 A3CR681 A3CR682 A3CR751 A3CR752 A3CR776 A3CR781 A3CR837 A3CR876 A3J153 152-- 0066-- 00 152-- 0269-- 01 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 0141-- 02 152-- 014
Replaceable Electrical Parts Component number Tektronix part number A3L146 108-- 1262-- 00 A3L185 108-- 0317-- 00 A3L337 108-- 0317-- 00 A3L353 108-- 0317-- 00 A3L433 108-- 1344-- 00 A3L437 108-- 0317-- 00 A3L451 108-- 0317-- 00 A3L533 108-- 0317-- 00 A3L642 108-- 1343-- 00 A3L750 108-- 0317-- 00 A3L791 108-- 0317-- 00 A3L845 108-- 1343-- 00 A3P245 131-- 0993-- 00 A3P696 131-- 0993-- 00 A3P796 131-- 0993-- 00 A3P915 131-- 0993-- 00 A3P916 131-- 0993-- 00 A3P917 131-- 09
Replaceable Electrical Parts Component number A3Q362 A3Q371 A3Q372 A3Q385 A3Q391 A3Q424 A3Q434 A3Q474 A3Q480 A3Q481 A3Q490 A3Q493 A3Q532 A3Q540 A3Q541 A3Q552 A3Q564 A3Q570 A3Q571 A3Q576 A3Q580 A3Q581 A3Q632 A3Q666 A3Q670 A3Q671 A3Q672 A3Q680 A3Q685 A3Q687 A3Q688 A3Q693 A3Q732 A3Q733 A3Q761 A3Q764 A3Q780 A3Q781 A3Q794 A3Q795 A3Q836 A3Q855 A3Q856 A3Q866 A3Q867 A3Q868 A3Q874 A3Q880 A3Q884 A3Q896 A3Q897 A3Q966 A3Q967 A3Q975 A3Q994 8- 22 Tektronix part number 151-- 1025-- 00 151-- 0190-- 00 151-- 0195-- 00 15
Replaceable Electrical Parts Component number A3R135 A3R136 A3R137 A3R138 A3R142 A3R143 A3R144 A3R152 A3R157 A3R158 A3R166 A3R167 A3R170 A3R171 A3R172 A3R173 A3R174 A3R175 A3R177 A3R178 A3R181 A3R182 A3R183 A3R184 A3R185 A3R186 A3R187 A3R189 A3R190 A3R191 A3R194 A3R198 A3R212 A3R221 A3R222 A3R223 A3R224 A3R232 A3R233 A3R234 A3R235 A3R236 A3R237 A3R238 A3R239 A3R240 A3R241 A3R242 A3R243 A3R244 A3R245 A3R246 A3R247 A3R248 A3R250 1720/1721 Tektronix part number 322-- 3230-- 00 322-- 3318-- 00 322-- 3314-- 0
Replaceable Electrical Parts Component number A3R252 A3R253 A3R254 A3R255 A3R259 A3R267 A3R280 A3R281 A3R282 A3R283 A3R284 A3R285 A3R286 A3R287 A3R288 A3R289 A3R292 A3R293 A3R294 A3R295 A3R328 A3R331 A3R332 A3R333 A3R334 A3R341 A3R342 A3R343 A3R346 A3R347 A3R348 A3R353 A3R354 A3R355 A3R356 A3R357 A3R358 A3R362 A3R363 A3R368 A3R369 A3R381 A3R382 A3R383 A3R384 A3R385 A3R386 A3R387 A3R388 A3R389 A3R390 A3R395 A3R396 A3R397 8- 24 Tektronix part number 322-- 3198-- 00 322-- 3260-- 00 322-- 3097-- 00 322-- 309
Replaceable Electrical Parts Component number Tektronix part number A3R424 322-- 3289-- 00 A3R428 A3R431 A3R432 A3R433 A3R441 A3R442 A3R443 A3R444 A3R445 A3R446 A3R447 A3R448 A3R449 A3R453 A3R454 A3R455 A3R455 A3R455 A3R457 A3R458 A3R459 A3R460 A3R462 A3R463 A3R464 A3R465 A3R466 A3R467 A3R470 A3R471 A3R472 A3R474 A3R483 A3R484 A3R486 A3R491 A3R492 A3R502 A3R508 A3R518 A3R522 A3R528 A3R530 A3R534 A3R536 A3R540 A3R542 A3R547 A3R548 A3R549 A3R554 A3R554 322-- 3289-- 00 322-- 3185-- 00 322-- 3318-- 00 322
Replaceable Electrical Parts Component number A3R554 A3R557 A3R558 A3R559 A3R562 A3R563 A3R566 A3R567 A3R568 A3R569 A3R570 A3R571 A3R574 A3R575 A3R576 A3R578 A3R579 A3R581 A3R582 A3R583 A3R593 A3R594 A3R595 A3R596 A3R602 A3R603 A3R605 A3R606 A3R609 A3R616 A3R631 A3R632 A3R633 A3R634 A3R635 A3R636 A3R637 A3R638 A3R639 A3R642 A3R643 A3R644 A3R645 A3R646 A3R647 A3R647 A3R647 A3R648 A3R649 A3R650 A3R651 A3R652 A3R653 A3R654 A3R655 8- 26 Tektronix part number 322-- 3148-- 00 322-- 3162-- 00 322-- 3097-- 00 32
Replaceable Electrical Parts Component number A3R656 A3R657 A3R658 A3R661 A3R662 A3R663 A3R664 A3R665 A3R666 A3R667 A3R668 A3R669 A3R670 A3R671 A3R672 A3R674 A3R675 A3R676 A3R677 A3R680 A3R682 A3R683 A3R684 A3R685 A3R686 A3R687 A3R691 A3R692 A3R693 A3R694 A3R702 A3R703 A3R734 A3R735 A3R736 A3R737 A3R738 A3R739 A3R740 A3R741 A3R742 A3R743 A3R744 A3R745 A3R746 A3R747 A3R748 A3R749 A3R750 A3R752 A3R760 A3R761 A3R762 A3R763 A3R764 1720/1721 Tektronix part number 322-- 3177-- 00 322-- 3097-- 00 322-- 3097-- 0
Replaceable Electrical Parts Component number A3R765 A3R766 A3R767 A3R768 A3R770 A3R771 A3R772 A3R773 A3R774 A3R775 A3R776 A3R777 A3R780 A3R781 A3R782 A3R786 A3R791 A3R830 A3R831 A3R832 A3R833 A3R834 A3R837 A3R839 A3R840 A3R841 A3R842 A3R843 A3R845 A3R846 A3R847 A3R848 A3R849 A3R855 A3R856 A3R857 A3R858 A3R868 A3R869 A3R870 A3R871 A3R872 A3R873 A3R873 A3R873 A3R874 A3R875 A3R876 A3R877 A3R878 A3R880 A3R882 A3R883 A3R884 A3R885 8- 28 Tektronix part number 322-- 3097-- 00 322-- 3193-- 00 322-- 3277-- 00 32
Replaceable Electrical Parts Component number Tektronix part number A3R890 A3R891 A3R892 A3R893 A3R894 A3R895 A3R896 A3R921 A3R937 A3R938 A3R939 A3R940 A3R941 A3R942 A3R943 A3R944 A3R945 A3R946 A3R947 A3R948 A3R952 A3R953 A3R954 A3R955 A3R956 A3R957 A3R958 A3R967 A3R969 A3R971 A3R972 A3R975 A3R976 A3R984 A3R990 A3R991 A3R992 A3R994 A3U164 A3U172 A3U184 322-- 3289-- 00 322-- 3269-- 02 322-- 3154-- 00 322-- 3230-- 00 322-- 3226-- 00 322-- 3222-- 00 322-- 3239-- 00 322-- 3322-- 00 322-- 3222-- 00 322-- 322
Replaceable Electrical Parts Component number Tektronix part number A3U440 156-- 0048-- 00 A3U446 A3U467 A3U505 A3U508 A3U585 A3U613 156-- 0411-- 00 156-- 2460-- 00 156-- 1126-- 00 156-- 0991-- 00 156-- 1850-- 00 160-- 4202-- 01 050-- 2297-- 02 160-- 4202-- 02 Serial / Assembly number Effective Discontinued B012271 B068300 B010790 B012271 B010790 B068301 B077737 B077736 B068300 B077736 136-- 0757-- 00 A3U640 A3U646 A3U659 A3U734 A3U739 A3U757 A3U774 A3U818 A3U854 A3U876 A3U884 A3U889 A3U942 A3U
Replaceable Electrical Parts Component number A3A1DS100 Tektronix part number Serial / Assembly number Effective Discontinued 150-- 0168-- 00 LAMP,INCAND:14V,0.08A,WEDGE BASE,T1.75 FOR SKT MT *MOUNTING PARTS* SOCKET, LPHLDR:PCB,LAMPHOLDER,FEMALE,STR, SINGLE 0.404H X 0.218 TAIL TIN, T-- 1.75 WEDGE BASE *END MOUNTING PARTS* LAMP,INCAND:14V,0.08A,WEDGE BASE,T1.75 FOR SKT MT *MOUNTING PARTS* SOCKET, LPHLDR:PCB,LAMPHOLDER,FEMALE,STR, SINGLE 0.404H X 0.218 TAIL TIN, T-- 1.
Replaceable Electrical Parts Component number Tektronix part number Serial / Assembly number Effective Discontinued Name & description Mfr. code Mfr. part number A11 A11J2 671-- 3761-- 00 131-- 3925-- 00 CKT BD ASSY:SERIAL FILTER CONN,DSUB:PCB,FEMALE,RTANG,9 POS,0.112 CTR,0.318 MLG X 0.125 TAIL,4-- 40 THD INSERT,BD RETE 80009 00779 671376100 747844-- 4 S1 260-- 2465-- 00 SWITCH,PUSH:0.4A,125VAC,W/SOLDER LUG,BUTTON *ATTACHED PARTS* CA ASSY,SP:RIBBON,POWER SWITCH;MIXED/CRIMP,2,26 AWG,3.5 L,0.
Diagrams/Circuit Board Illustrations
Replaceable Mechanical Parts
Replaceable Mechanical Parts This section contains a list of the components that are replaceable for the 1720/1721. Use this list to identify and order replacement parts. There is a separate Replaceable Mechanical Parts list for each instrument. Parts Ordering Information Replacement parts are available from or through your local Tektronix, Inc., Field Office or representative.
Replaceable Mechanical Parts Chassis Parts Chassis-mounted parts and cable assemblies are located at the end of the Replaceable Electrical Parts list. Column Descriptions Figure & Index No. (Column 1) Items in this section are referenced by figure and index numbers to the illustrations. Tektronix Part No. (Column 2) Indicates part number to be used when ordering replacement part from Tektronix. Serial No.
Replaceable Mechanical Parts Cross Index - Mfr. Code Number To Manufacturer Mfr.
Replaceable Mechanical Parts Replaceable Mechanical Parts Fig. & index no. Tektronix part no.
Replaceable Mechanical Parts Fig. & index no. Tektronix part no.
Replaceable Mechanical Parts Fig. & index no. - 48 - 49 Tektronix part no.
Replaceable Mechanical Parts Fig. & index no. Tektronix part no. Serial number Effective Dscont Qt y 016-- 0475-- 00 200-- 3897-- 01 ----------- 1 1 1 --------------------------------------------------- 1 1 1 1 1 1720/1721 Name & description VIEWING HOOD:1740 COVER,FRONT:1700F02,HOT STAMPED CAMERA,SCOPE:C9 (OPTION 20 ONLY) PLAIN CASE ASSY:1700F00 PTD CASE ASSY:1700F02 RACK ADAPTER:1700F05 FILLER PANEL:1700F06 DRAWER,UTILITY:1700F07 Mfr. code Mfr. part no.
Replaceable Mechanical Parts 10- 8 1720/1721
