Harman Kardon AVR 525, Service Manual

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7) Replace the DSP and Processor boards
8) Recheck all bias voltages, following the instructions below:
MAIN AMP IDLE CURRENT ADJUSTMENT PROCEDURE
(Set variable resistors for MAIN/SURROUND Board)
Specialized equipment/parts needed:
Variable AC transformer (“Variac” type) to adjust and monitor AC line voltage.
Two pin harness plug to connect DMM to idle current test points, hk part# 55212910NR or equivalent
Conditions:
No Signal; No Load
AC Line Voltage adjust to: 120V/60Hz (120v model) or 230V/50Hz (230v model)
After turning the unit ON for 25 minutes or more to keep the Power/Driver TR at normal temperature,
adjust the DC voltage at the two pin connector to the specified value by rotating the variable resistors.
VR71-74 are located on the Bias PCB’s.
P801-804 are located on the main PCB just below the Bias PCB’s. To guide/seat the two pin harness plug
into the sockets, you may have to attach the harness wire to a long blade screwdriver as P801-803 are in
a deep recess.
CHANNEL ADJUSTMENT MEASUREMENT POINT VOLTAGE
FRONT L CHAN VR71 P801 23mV ±2mV
FRONT R CHAN VR74 P804 23mV ±2mV
SURROUND L CHAN VR73 P803 23mV ±2mV
SURROUND R CHAN VR72 P802 23mV ±2mV
SURROUND BACK AMP IDLE CURRENT ADJUSTMENT PROCEDURE
Same conditions as above.
After turning the unit ON for 25 minutes or more to keep the Power/Driver TR at normal temperature,
adjust the voltage value at the two pin connector to the specified value by rotating the variable resistors.
AVR325-525: VR31,41,51 and P301,308,309 are located at the center of the Surround PCB
AVR430-630: VR31,32,51 and P301,308,309 are located at the top edge of the Surround PCB
CHANNEL ADJUSTMENT MEASUREMENT POINT VOLTAGE
AVR325-525 VR41 P308
CENTER
AVR430-630 VR32 P308
23mV ±2mV
SURROUND BACK L VR31 P301 23mV ±2mV
SURROUND BACK R VR51 P309 23mV ±2mV
9) After 5 minutes, check all voltages again at measurement points and re-adjust if necessary.
10) After more 5 minutes, check all voltages again at measurement points and re-adjust if necessary.
11) Replace the top cover and test the unit.
Model
Serial Number (120v) Serial Number (230v)
Status Action
AVR325 All serial numbers affected n/a
Unit may shut down or fan
may run continuously
Hard wire bias cables
to PCB’s
AVR525
All serial numbers affected n/a
Unit may shut down or fan
may run continuously
Hard wire bias cables
to PCB’s
AVR430
TF0001-01000
to
TF0001-08116
TF0006-01000
to
TF0006-06663
Unit may shut down or fan
may run continuously
Hard wire bias cables
to PCB’s
AVR430
TF0007-08117 and above TF0007-06664 and above Modified by Factory None Required
AVR630
TF0002-01000
to
TF0002-11138
TF0007-01000
to
TF0007-05650
Unit may shut down or fan
may run continuously
Hard wire bias cables
to PCB’s
AVR630
TF0002-11139 and above TF0007-05651 and above Modified by Factory None Required
AVR525
harman/kardon
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