Onkyo SKW-204(B)/(S)/(Y)-Powered Subwoofer Circuit diagram, exploded view, Current adjustment

Black, Silver and Yellow models

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 multi-meter becomes 52 ohm to 53 ohm.
3. Connect the DC voltmeter to test point P531. 

4. Connect the AC power cord into a wall outlet.
5. Press POWER button to turn on the unit.
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 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 so that the voltage becomes 5.0 mV to 5.5 mV.
When 10.1 mV to 20.0 mV : Readjust the trimming resistor so that the voltage becomes 5.6 mV to 6.0 mV.
8. Press POWER button to turn off the unit.
9. Disconnect the DC voltmeter.
10. Disconnect the AC power cord from a wall outlet.

Circuit diagram (Schematic),PWB and Exploded view

Click on the pictures to magnify