Page 2 - CAUTION
Micro-Tech 1200 Amplifier Service Manual 2 À PRÉVENIR LE CHOC ÉLECTRIQUE N’ENLEVEZ PAS LES COUVERTURES. RIEN DES PARTIES UTILES À L’INTÉRIEUR. DÉBRANCHER LA BORNE AVANT D’OUVRIR LA MODULE EN ARRIÈRE. TO PREVENT ELECTRIC SHOCK DO NOT REMOVE TOP OR BOTTOM COVERS. NO USER SERVICEABLEPARTS INSIDE. REFER...
Page 3 - Table of Contents
Micro-Tech 1200 Amplifier Service Manual 3 Introduction ............................................................. 4Scope ...................................................................... 4Warranty .................................................................. 4Parts Information ...........
Page 4 - Crown; SCOPE; Introduction
Micro-Tech 1200 Amplifier Service Manual 4 Crown Technical Support Group Factory Service Parts Department Mailing Address: PO Box 1000 Elkhart, IN USA 46515-1000 Shipping Address: 57620 C.R. 105 Elkhart, IN USA 46517 Phone: (219) 294-8200 Toll Free: (800) 342-6939 FAX: (219) 294-8301 This manual con...
Page 5 - Parts Information
Micro-Tech 1200 Amplifier Service Manual 5 Parts Information shipment on a C.O.D. or pre-payment (check or creditcard) basis. TERMS Normal terms are pre-paid. Net-30 Days applies toonly those firms having pre-established accounts withCrown. If pre-paying, the order must be packed andweighed before a...
Page 6 - Specifications
Micro-Tech 1200 Amplifier Service Manual 6 Specifications Unless noted otherwise, all specifications are basedon driving an 8 ohm load per channel, both channelsdriven, the sensitivity switch in the 26dB position, theAC supply is 120VAC at 60Hz. Crown specificationsare guaranteed through the warrant...
Page 7 - Voltage Conversion; VOLTAGE SELECTION BOARD
Micro-Tech 1200 Amplifier Service Manual 7 Voltage Conversion The 120 Volt 60 Hz version, sold in the United States,is not voltage selectable. It does not have voltageselection boards. This version is to be used only with120 Volts and only with 60Hz. All other versions of the Micro Tech 1200 use vol...
Page 8 - Theory; OVERVIEW
Micro-Tech 1200 Amplifier Service Manual 8 Theory OVERVIEW It should be noted that over time Crown makes im-provements and changes to their products for variousreasons. This manual is up to date as of the time ofwriting. For additional information regarding theseamplifiers, refer to the applicable T...
Page 9 - VOLTAGE AMPLIFICATION; GROUNDED BRIDGE TOPOLOGY
Micro-Tech 1200 Amplifier Service Manual 9 Theory amplifies the difference between input and outputsignals, any difference in the two waveforms willproduce a near open loop gain condition which in turnresults in high peak output voltage. The output of theError Amp, called the Error Signal (ES) drive...
Page 11 - OUTPUT DEVICE EMULATION PROTECTION
Micro-Tech 1200 Amplifier Service Manual 11 respect to each other. This allows the power supply todeliver +Vcc and -Vcc from the same bridge rectifierand filter as a total difference in potential, regardlessof their voltages with respect to ground. The LS usesinverted feedback from the HS output to ...
Page 13 - Electrical Checkout Procedures; GENERAL INFORMATION
Micro-Tech 1200 Amplifier Service Manual 13 Electrical Checkout Procedures GENERAL INFORMATION The following test procedures are to be used to verifyoperation of this amplifier. DO NOT connect a load orinject a signal unless directed to do so by the proce-dure. These tests, though meant for verifica...
Page 14 - In
Micro-Tech 1200 Amplifier Service Manual 14 TEST 4: AC POWER DRAW Spec: 100 Watts maximum quiescent. Initial Conditions: Controls per standard. Procedure: With no input signal and no load, measure AC line wattage draw. If current draw is excessive,check for high AC line voltage or high bias voltage....
Page 16 - TEST 19: INTERMODULATION DISTORTION; POST TESTING
Micro-Tech 1200 Amplifier Service Manual 16 Spec: No dangerous transients. Initial Conditions: Controls per standard. Procedure: From an on condition, turn off the amplifier and monitor the output noise at the time of turn off. Note:Turn off noise may increase significantly if the amplifieris cycled...
Page 17 - SUPPLIMENTAL ITEMS
Micro-Tech 1200 Amplifier Service Manual 17 Parts List (Non-Module) SUPPLIMENTAL ITEMS CPN ITEM QTY D 4137-2 Nylon Thumbscrew Washer 4 C 3342-0 Feet, Black Self-Stick 4 A10087-71012 10-32 .75 Machine (Rack Screw) 4 K80583-6 MT Series Owners Manual 1 POWER SUPPLY CPN ITEM QTY M43534-3 MT Fuse Board A...
Page 18 - BACK PANEL ASSEMBLY
Micro-Tech 1200 Amplifier Service Manual 18 Parts List (Non-Module) OUTPUT ASSEMBLY (CONT.) CPN ITEM QTY (ONE PER CHANNEL) D 8774-8 PTC, 95 Deg. Thermal Sensor 1 F12019-0 Aluminum Heatsink Slug (under diodes on output mod) 1 C 8813-5 MPS8097/MPSA18 NPN Transistor (Q318/Q418) 1 B 5842-8 #23 Tubing fo...
Page 20 - Module and Schematic Information; MODULE HISTORY
Micro-Tech 1200 Amplifier Service Manual 20 Module and Schematic Information MODULE HISTORY The Micro Tech 1200 amplifier was introduced inJanuary 1986. Since then there have been severalupdates and revisions, some of which called for newmodules. The following is a list of all modules used upto this...
Page 21 - Fuse and Display Module Parts Lists
Micro-Tech 1200 Amplifier Service Manual 21 Fuse and Display Module Parts Lists Q43061-3 ODEP DISPLAY MODULE CAPACITORS C503 C603 C 6806-1 .01µF 100V C507 C607 C 6809-5 220pF 100V C701 C 6802-0 .47µF 50V C702 C 6802-0 .47µF 50V DIODES D701 C 3533-4 1N966B 16V Zener D702 C 3533-4 1N966B 16V Zener LED...
Page 28 - CAPACITORS; TRANSISTORS
Micro-Tech 1200 Amplifier Service Manual 28 CAPACITORS C1 C 4303-1 1000uF C2 C 3913-8 470uF C3 C 4303-1 1000uF C4 C 6802-0 .47uF C100 C200 C 5053-1 18uF C101 C201 C 2821-4 10pF C103 C203 C 6805-3 .022uF C104 C204 C 6805-3 .022uF C105 C205 C 6950-7 82pF C106 C206 C 6950-7 82pF C108 C208 C 6812-9 47pF...
Page 29 - SWITCHES
Micro-Tech 1200 Amplifier Service Manual 29 R116 R216 A10266-3351 3.3M R118 R218 A10266-2711 270 OHM R119 R219 A10266-3011 300 OHM R120 R220 A10266-2711 270 OHM R121 R221 C 5062-2 100K TRIM R122 R222 A10266-2741 270K R123 R223 A10266-1831 18K R124 R224 A10266-6821 6.8K R125 R225 C 7782-3 100 OHM R12...
Page 32 - DIODES
Micro-Tech 1200 Amplifier Service Manual 32 CAPACITORS C1 C 3913-8 470µF C2 C 3913-8 470µF C4 C 6802-0 .47µF C5 C 6806-1 .01µF C6 C 6806-1 .01µF C7 C 6094-9 33µF C8 C 6806-1 .01µF C100 C200 C 5311-3 22µF C101 C201 C 2820-6 5pF C103 C203 C 6805-3 .022µF C104 C204 C 6804-6 .1µF C105 C205 C 6812-9 47pF...
Page 33 - RESISTORS
Micro-Tech 1200 Amplifier Service Manual 33 Q116 Q216 C 3786-8 PN4250A Q117 Q217 D 2961-7 2N3859A Q118 Q218 D 2961-7 2N3859A Q119 Q219 C 3625-8 2N4125 Q120 Q220 C 3625-8 2N4125 Q121 Q221 C 7458-0 2N4123 Q122 Q222 C 7458-0 2N4123 RESISTORS R1 A10265-53621 53.6K R2 A10266-2402 24 OHM R3 A10266-2402 24...
Page 34 - INTEGRATED CIRCUITS
Micro-Tech 1200 Amplifier Service Manual 34 INTEGRATED CIRCUITS U1 C 5095-2 MC7815 U2 C 5096-0 MC7915 U100 U200 C 6911-9 UPA75 PNP U103 U203 C 6910-1 UPA76 NPN U104 U204 C 6900-2 MC34084P CONNECTORS J1 C 7593-4 HDR, 5 PIN J2 C 4508-5 16 PIN Soc J9 C 7527-2 HDR, 6 PIN J10 C 7592-6 HDR, 4 PIN J11 C 75...
Page 39 - RESISTOR NETWORKS
Micro-Tech 1200 Amplifier Service Manual 39 Q43035-7 Main Module (D7993-5 board) Parts List Cont. Q122 Q222 C 7458-0 NPN 2N4123 Q123 Q223 C 7458-0 NPN 2N4123 Q124 Q224 C 3625-8 NPN 2N4125 RESISTOR NETWORKS N101 N201 D 7946-3 Resistor Network N102 N202 D 6082-8 Resistor Network RESISTORS R1 A10265-53...
