Micro-Tech 2400 Amplifier Service Manual POWER AMPLIFIER SERVICE MANUAL MICRO-TECH -2400 ® ©1995 by CROWN INTERNATIONAL, INC. Mailing Address: P.O. Box 1000 Elkhart, IN U.S.A. 46515-1000 Shipping Address: 57620 C.R. 105 Elkhart, IN U.S.A. 46517 Micro-Tech®, ODEP® and Crown® are registered trademarks of Crown International, Inc.
Micro-Tech 2400 Amplifier Service Manual The information furnished in this manual does not include all of the details of design, production, or variations of the equipment. Nor does it cover every possible situation which may arise during installation, operation or maintenance. If you need special assistance beyond the scope of this manual, please contact the Crown Technical Support Group. Mail: P.O. Box 1000 Elkhart IN 46515-1000 Shipping: 57620 C.R.
Micro-Tech 2400 Amplifier Service Manual Table of Contents Introduction ............................................................. 4 Scope ...................................................................... 4 Warranty .................................................................. 4 Parts Information ..................................................... 5 Specifications .......................................................... 6 Voltage Conversion .................................................
Micro-Tech 2400 Amplifier Service Manual Introduction This manual contains service information on Crown power amplifiers. It is designed to be used in conjunction with the applicable Owner's Manual. However, some important information is duplicated in this Service Manual in case the Owner's Manual is not readily available. Each of the compact audio power amplifiers are designed for professional or commercial use.
Micro-Tech 2400 Amplifier Service Manual Parts Information GENERAL INFORMATION Later sections include both mechanical and electrical parts lists for this product. The parts listed are current as of the date printed. Crown reserves the right to modify and improve its products for the benefit of its customers. PART NUMBERING SYSTEMS As of the printing of this manual, Crown is using two numbering systems. The elder system always uses eight characters. The first character is a letter.
Micro-Tech 2400 Amplifier Service Manual Specifications Unless noted otherwise, all specifications are based on driving an 8 ohm load per channel, both channels driven, the sensitivity switch in the 26dB position, the AC supply is 120VAC at 60Hz. Crown specifications are guaranteed through the warranty period (normally 3 years). Because our testing methods are more stringent than our published specifications, every Crown amplifier will exceed its published specifications.
Micro-Tech 2400 Amplifier Service Manual Voltage Conversion The 120 Volt 60 Hz version, sold in the United States, is not voltage selectable. It does not have a voltage selection board. This version is to be used only with 120 Volts and only with 60Hz. All other versions of the Micro Tech 2400 use a voltage selection board. The following chart indicates different configurations of jumpers for different voltages.
Micro-Tech 2400 Amplifier Service Manual Theory OVERVIEW It should be noted that over time Crown makes improvements and changes to their products for various reasons. This manual is up to date as of the time of writing. For additional information regarding these amplifiers, refer to the applicable Technical Notes provided by Crown for this product. This section of the manual explains the general operation of a typical Crown power amplifier. Topics covered include Front End, Grounded Bridge, and ODEP.
Micro-Tech 2400 Amplifier Service Manual Theory The ODEP transistors steal drive as dictated by the ODEP circuitry (discussed later). The control/protection transistors act as switches to totally shunt audio to ground during the turn-on delay, or during a DC/LF or Fault protective action. amplifies the difference between input and output signals, any difference in the two waveforms will produce a near open loop gain condition which in turn results in high peak output voltage.
Micro-Tech 2400 Amplifier Service Manual Theory High Side (HS) The High Side (HS) of the bridge operates much like a conventional bipolar push-pull output configuration. As the input drive voltage becomes more positive, the HS NPN conducts and delivers positive voltage to the load. Eventually the NPN devices reach full conduction and +Vcc is across the load. At this time the HS PNP is biased off.
Micro-Tech 2400 Amplifier Service Manual Theory respect to each other. This allows the power supply to deliver +Vcc and -Vcc from the same bridge rectifier and filter as a total difference in potential, regardless of their voltages with respect to ground. The LS uses inverted feedback from the HS output to control the ground reference for the rails (±Vcc). Both LS quadrants are arranged in a three-deep Darlington and are biased AB+B in the same manner as the HS.
Micro-Tech 2400 Amplifier Service Manual Theory BGS BALANCED INPUTS VGS -1 POSITIVE HIGH SIDE OUTPUT NPN STAGE +LVA -1 +VOLTAGE TRANSLATOR ERROR AMP OUTPUT DEVICE EMULATION PROTECTION HIGH SIDE BIAS SERVO NEGATIVE HIGH SIDE OUTPUT PNP STAGE -LVA -1 -VOLTAGE TRANSLATOR MAIN NEGATIVE FEEDBACK (NFb) LOOP POSITIVE LOW SIDE OUTPUT NPN STAGE -1 INVERTING BRIDGE BALANCE LOW SIDE BIAS DIODE STRING NEGATIVE LOW SIDE OUTPUT PNP STAGE Figure 3.
Micro-Tech 2400 Amplifier Service Manual Electrical Checkout Procedures GENERAL INFORMATION The following test procedures are to be used to verify operation of this amplifier. DO NOT connect a load or inject a signal unless directed to do so by the procedure. These tests, though meant for verification and alignment of the amplifier, may also be very helpful in troubleshooting. For best results, tests should be performed in order. All tests assume that AC power is from a regulated 120 VAC source.
Micro-Tech 2400 Amplifier Service Manual Electrical Checkout Procedures TEST 6: VOLTAGE GAIN TEST 10: SLEW RATE & 10 KHZ SQUARE WAVE Spec 26dB Gain: Gain of 20.0 ±3%. Spec 0.775V Sensitivity: ±6%. Spec 1.4V Sensitivity: +12%/–6%. Initial Conditions: Controls per standard. Procedure: No load connected. Inject a 0.775 VAC 1 kHz sine wave with the Sensitivity Switch in the 26 dB position. Measure 15.5 VAC ±0.5 VAC at the amplifier output. Inject a 0.
Micro-Tech 2400 Amplifier Service Manual Electrical Checkout Procedures Procedure Short: Inject a 60 Hz sine wave at 5 VAC minimum output. After establishing signal, short the output for 10 seconds. TEST 14: ODEP LIMITING Spec: No oscillation on ODEP Limiting wave form; either channel controls limiting in Parallel Mono Mode. Initial Conditions: Controls per standard; rag or other obstruction blocking fan so that it does not turn. Procedure: Load the amplifier to 4 ohms on each channel.
Micro-Tech 2400 Amplifier Service Manual Parts List (Non-Module) SUPPLIMENTAL ITEMS CPN D 4137-2 C 3342-0 A10087-71012 K80603-2 ITEM Nylon Thumbscrew Washer Feet, Black Self-Stick 10-32 .75 Machine (Rack Screw) MT Series Owners Manual QTY 4 4 4 1 ITEM Power Cord (US Models) Power Cord (European plug) Power Transformer (120V 60 Hz only) Power Transformer (Universal Volt) Circuit Breaker, 15A (100V-120V) Circuit Breaker, 7.5A (200V-240V) Fuse, 1A 3AG (100V-120V) Fuse, .
Micro-Tech 2400 Amplifier Service Manual Parts List (Non-Module) OUTPUT ASSEMBLY CONT. (ONE PER CHANNEL) CPN D 7665-9 D 7666-7 C 8813-5 B 5842-8 C 5826-0 B 5464-1 D 8774-8 A10315-1 C 9491-9 D 7796-2 D 7797-0 D 8197-2 C 9387-9 F12019-0 M21322J8 ITEM Clip, TO-3P Mounting Bracket, TO-3P Heatsink Q318/Q418 Bias Servo MPSA18/MPS8097 Tubing, #23 TFE Thin Wall Red (For C 8813-5) S100/S200 Thermal Sense LM334Z Tubing, #24 Teflon Thin Wall (For C 5826-0) PTC Thermal Sensor 95DEGC Screw, 6-32-.
Micro-Tech 2400 Amplifier Service Manual Parts List (Non-Module) MAIN CHASSIS ASSEMBLY CPN D 8501-5 D 8548-6 A10110-70605 M21447J3 ITEM Cover, Top Cover, Bottom Screw, 6-32-.312 Taptite Ph (Covers) Main Chassis QTY 1 1 16 1 ITEM 8-32 x .750 Taptite Pnhd Screw Washer, #6 Black Star Screw, 8-18-1.375 Pan Ph Snap Bushing .5 Tension Retainer Board Support Spacer Nut, 1 inch Spacer Nut, .75 inch 5.5" Cable Tie 7.5" Cable Tie & Clamp 15" Cable Tie 16.
Micro-Tech 2400 Amplifier Service Manual Module Information MODULE HISTORY The Micro Tech 2400 amplifier was introduced in January of 1995. Since then there have been several updates and revisions, some of which called for new modules. The following is a list of all modules used up to this date, July 1995. OUTPUT MODULES: (left and right are identical) Q43354-2 Original Output Module, still in production. Uses P10429-2 board. MAIN MODULES: Q43328-6 Original Main Module on D 8679-9 board.
Micro-Tech 2400 Amplifier Service Manual M46330-3 Fuse Module & Q43327-8 Display Module Parts List M46330-3 FUSE MODULE 2 11 1 C 5060-6 C 7817-7 P10425-0 PC Mount Fuse Clip Tab, AMP .25 Faston PC Mount MT-2400 Fuse Board For replacement fuse see Power Supply Parts List on page 16. Q43327-8 DISPLAY MODULE CAPACITORS C503 C507 C701 C702 C603 C607 C 6806-1 C 6809-5 C 6802-0 C 6802-0 .01µF 220pF .47µF .
Micro-Tech 2400 Amplifier Service Manual Q43354-2 Output Module Parts List (P10429-2 Board) Q43354-2 Output Module for MT-2400. For Schematic See J0658-5 CAPACITORS C01 C02 C03 C04 C05 C06 C07 C08 C09 C43 C 8511-5 C 8426-6 C 8426-6 C 6806-1 C 6806-1 C 6806-1 C 6807-9 C 6810-3 C 6809-5 C 7697-3 .047µF .1µF .1µF .01µF .01µF .01µF .001µF 180pF 220pF .
Micro-Tech 2400 Amplifier Service Manual Q43328-6 Main Module Parts List (D8679-9 Board) Q43328-6 MT-2400 ORIGINAL MAIN MODULE Use Schematic J 0658-5 CAPACITORS C1 C2 C4 C5 C6 C7 C8 C100 C101 C102 C103 C104 C105 C106 C107 C108 C109 C110 C112 C113 C114 C115 C116 C117 C118 C119 C122 C123 C124 C129 C130 C132 C133 C134 C135 C136 C137 C138 C139 C140 C141 C144 C145 C146 C147 C148 C149 C150 22 C200 C201 C202 C203 C204 C205 C206 C207 C208 C209 C210 C212 C213 C214 C215 C216 C217 C218 C219 C222 C223 C224 C229 C230
Micro-Tech 2400 Amplifier Service Manual Q43328-6 Main Module Parts List Cont. (D8679-9 Board) RESISTOR NETWORKS N101 N102 N201 N202 D 7944-8 D 6082-8 Res. Net. Res. Net.
Micro-Tech 2400 Amplifier Service Manual Q43328-6 Main Module Parts List Cont.
Micro-Tech 2400 Amplifier Service Manual Q43328-6 Main Module Parts List Cont. (D8679-9 Board) J500 J800 J600 J700 HW5-8 Z1-Z5 D 8681-5 D 8680-7 C 8812-7 OPEN 10 In. RBN 6 In. RBN 5.
Micro-Tech 2400 Amplifier Service Manual Q43399-7 Main Module Parts List (D8827-4 Board) Q43399-7 MT-2400 MAIN MODULE Use Schematic J 0691-6 CAPACITORS C1 C2 C4 C5 C6 C7 C8 C100 C101 C102 C103 C104 C105 C106 C107 C108 C109 C110 C112 C113 C114 C115 C116 C117 C118 C119 C122 C123 C124 C129 C130 C133 C134 C135 C136 C137 C138 C139 C140 C141 C144 C145 C146 C147 C148 C149 C150 C151 26 C200 C201 C202 C203 C204 C205 C206 C207 C208 C209 C210 C212 C213 C214 C215 C216 C217 C218 C219 C222 C223 C224 C229 C230 C233 C23
Micro-Tech 2400 Amplifier Service Manual Q43399-7 Main Module Parts List Cont. (D8827-4 Board) RESISTOR NETWORKS N101 N102 N201 N202 D 7944-8 D 6082-8 Res. Net. Res. Net.
Micro-Tech 2400 Amplifier Service Manual Q43399-7 Main Module Parts List Cont.
Micro-Tech 2400 Amplifier Service Manual Q43399-7 Main Module Parts List Cont. (D8827-4 Board) U103A U203A OPEN MISC. Board Socket HW9-10 HW11-15 J1 J2 J11 J12 J100 J200 Cover J101 J201 J500 J800 J600 J700 HW5-8 Z1-Z5 D 8827-4 C 3450-1 C 9494-3 C 9944-7 C 7593-4 C 4508-5 C 7526-4 Not Used C 6777-4 C 6778-2 Not Used D 8681-5 D 8680-7 C 8812-7 OPEN 14 Pin Heatsinks Nyl. Spacer 5 Pin HDR 16 Pin 3 Pin HDR Ph. Jack Ph Jk CVR 10 In. RBN 6 In. RBN 5.