Adjustment Procedure - Onkyo HTR-550 Service Manual

ADJUSTMENT PROCEDURE-1

IDLING CURRENT ADJUSTMENT
[When]
1. Exchange Power transistor (Q6050 - Q6056, Q6060 - Q6066).
2. Amplifier PC board (NAAF-8779).
[Procedure]
<Note> No load and No signal
Refer to " ADJUSTMENT PROCEDURE-2 " for the adjustment points and the test points.
1. Before idling adjustment, turn the trimming resistors fully 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 a 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
Center
Front Left
Front Right
Surround Left
Surround Right
Surround Back Left
Surround Back Right
6. Wait for 4 - 6 minutes. (Heat running)
7. Re-adjust the trimming resistors as the following procedure.
Channel
Front Left, Front 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.
100 ohms
Jig terminal
(1/4 watt)
Mark Adjustment point
(Trimming resistor)
C R6040
L R6041
R R6042
SL
R6043
SR R6044
SBL R6045
SBR
R6046
Adjustment point Measured value
In below 9 mV
R6041, R6042
In case 9 - 11 mV
and R6040
In case over 11 mV
R6043, R6044,
In case below 6 mV
In case 6 - 8 mV
R6045 and R6046
In case over 8 mV
Test point
ID+
ID-
Measuring point Adjustment value
(Test point)
P6080 2.5 mV
P6081 2.5 mV
P6082 2.5 mV
1.5 mV
P6083
P6084 1.5 mV
P6085 1.5 mV
1.5 mV
P6086
Adjustment value
9 mV
Leave it as it is
11 mV
6 mV
Leave it as it is
8 mV
Idling currents are stabilized in about 10 minutes after power on.
HT-R550
Specifications
( In a stable state)
12 +/- 3 mV
9 +/- 3 mV