Yorkville Sound 3400 service manual the M1002 or M1002A circuit board to be serviced

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the M1002 or M1002A circuit board to be serviced.

STEP 1. Locate the assembly drawing for the version number printed on

the M1002 or M1002A circuit board to be serviced.

2.Remove all of the transistors coloured RED on the assembly drawing.

3.Measure and remove any of the diodes coloured BLUE on the assembly drawing that may be damaged. Replace a 1N4732A 1W 4V7 zener (#6459) {These components already exist on version 9 and higher, add only in versions 9 and lower.] that may have been added to the component side of the board along with a series 0.5 ohm resistor. Refer to figure 1.

Figure 1

4.Rotate the trim pot RT1 fully counter - clockwise as in figure 2. Inspect and replace any resistors that look burnt. Measure all of the resistor values coloured YELLOW on the assembly drawing. The value that you measure may not be exactly what is shown on the assembly drawing but if the resistor doesn’t look damaged it should measure within + or – 5% of the printed value.

Figure 2

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Contents 3400 HIGH EFFICIENCY STEREO POWER AMPLIFIERQuality and Innovation Since CANADAPower Sources IMPORTANT SAFETY INSTRUCTIONSREFER SERVICING TO QUALIFIED SERVICE PERSONNEL Power CordCIRCUIT DESCRIPTION VOLTAGE AMPLIFIERSHUTDOWN CIRCUIT CIRCUIT DESCRIPTIONTHE SECOND TIER QUIESCENT CONDITIONCurrent Limit Protection Circuitry DC ProtectionConditions of test Fan Circuit EMS CircuitThermal Shutdown Circuit Identifying Defective Boards in the AP-3400STEP 3 POWER UP PROCEDURE WITHOUT M1002A BOARDS SPECIFICATIONSSTEP 4 DISMANTLING AND REASSEMBLY PRECAUTIONS POWERSTEP 4 DISMANTLING AND REASSEMBLY PRECAUTIONS STEP 3 POWER UP PROCEDURE WITHOUT M1002 BOARDSAP3400 Parts List 10/28/98 STEP 1 VISUAL INSPECTION OF FRONT PANEL AND FANM1011A.SCH DATABASE HISTORY M1002A.SCH DATABASE HISTORYM1013A.SCH DATABASE HISTORY MODELS - AP-3400 M1011A.SCH DATABASE HISTORYDATE VER# DESCRIPTION OF CHANGEMS2BOTTOMBAMP M1011ASHEAR SHEARM1011A.PCB DATABASE HISTORY M1011ALEFT = CHAN A RIGHT = CHAN BM1012 C8M1012SHEAR SHEARMPSA06 MJH110182N5551 B C E2N5551 MJH11018MPSA06 B C EAP-3400 M1013ACOPPER OZ SHEARM1002A AP-3400 5WATT@R55WATT Testing Repaired Circuit Board AP3000 AND AP3400 SERVICE Quick Fix for M1002 and M1002AYORKVILLE SOUND the M1002 or M1002A circuit board to be serviced If the AP-3400 M1002ASHEAR CHECKAP-3400CEXFMR WIRING NOV SHOWN WIRED FOR#1289 A C - W H I T EAP-3400CEXFMR WIRING NOV SHOWN WIRED FOR#1289 A C - W H I T E