Adjustment Procedure - Onkyo SKW-940 Service Manual

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ADJUSTMENT PROCEDURE

SKW-940 : POWERED SUBWOOFER / ADJUSTMENT OF IDLING CURRENT
[When]
1. Exchange transistors (Q505 - Q519).
2. Exchange MAIN PC board ass'y (NAAF-8829).
[Procedure]
<Note> No speaker load and No input signal.
1. Short test point P631 for amplifier is under active mode.
2. Adjust the trimming resistor R544 so that the reading of multimeter becomes 52 ohm to 53 ohm.
3. Connect the DC voltmeter to test point P531. <Fig-1>
4. Connect the AC power cord into a wall outlet.
5. Press POWER button to turn on the unit. (MPP type only)
6. Confirm the voltage of above point after 6 minutes to 8 minutes. (Heat running)
7. When less than 3.20 mV : Readjust the trimming resistor above so that the voltage becomes 4.5 mV to 5.0 mV.
When 3.30 mV to 5.20 mV : Not necessary to adjust.
When 5.21 mV to 10.0 mV : Readjust the trimming resistor above so that the voltage becomes 5.0 mV to 5.5 mV.
When 10.1 mV to 20.0 mV : Readjust the trimming resistor above so that the voltage becomes 5.6 mV to 6.0 mV.
8. Press POWER button to turn off the unit. (MPP type only)
9. Disconnect the DC voltmeter.
10. Disconnect the AC power cord from a wall outlet.
TE
L 13942296513
Trimming resistor
R544
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Test point
Test point
P531
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8
100 ohm
(1/4W)
<Fig-1>
Q Q
3 6 7 1 3 1 5
P531
MAIN PC board ass'y "NAAF-8829"
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9 4 2 8
DC voltmeter
0 5 8 2 9 9 4 2 8
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Test point
HTP-940
9 9
9 9
P631
Short