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ADJUSTMENT PROCEDURE-1
IDLING CURRENT ADJUSTMENT
[When]
1. Exchange the power transistors (Q6050 - 6056, Q6060 - 6066, Q6080 - 6086, Q6090 - 6096).
2. Exchange the amplifier PC board ass'y (NAAMP-9061, 9062, NACLA-9063 - 9069).
[Procedure]
<Note> No load and No signal
Refer to <Fig-1, 2, 3> in " ADJUSTMENT PROCEDURE-2, 3, 4 " for the adjustment points and the test points.
1. Before idling current adjustment, turn the trimming resistors to counter clockwise.
2. Connect the dc voltmeter to test points,
using two 100 ohm resistors between the poles of the jig terminal and the dc voltmeter terminals.
DC voltmeter
3. Connect the ac power cord to wall outlet.
4. Press STANDBY/ON button to turn the power on.
5. Adjust the trimming resistors as the following procedure immediately after power on.
Channel
Front Left
Front Right
Center
Surround Left
Surround Right
Surround Back Left
Surround Back Right
6. Wait for 4 to 6 minutes for heat running.
7. Re-adjust the trimming resistors as the following procedure.
Channel
Front Left, Right
and Center
Surround Left
Surround Right
Surround Back Left
Surround Back Right
8. Disconnect the dc voltmeter.
9. Press STANDBY/ON button to turn the power off.
10. Disconnect the ac power cord of the unit from the wall outlet.
100 ohms
Jig terminal
1/4watts
Connect
Adjustment point
Mark
(Trimming resistor)
R6040
L
R6041
R
R6042
C
R6043
SL
R6044
SR
R6045
SBL
R6046
SBR
Adjustment point
Measured value
R6040, R6041
In case below 3 mV
In case 3 - 4 mV
and R6042
In case over 4 mV
R6043
R6044
R6045
R6046
Test point
ID-
ID+
Measuring point
Adjustment value
(Test point)
P6070
3.0 mV
P6071
3.0 mV
P6072
3.0 mV
P6073
3.0 mV
P6074
3.0 mV
P6075
3.0 mV
P6076
3.0 mV
Adjustment value
3 mV
No re-adjustment
4 mV
Idling currents are stabilized in about
10 minutes after power on.
TX-SR875
Specifications
( In a stable state)
3 +/- 1 mV
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