Test L: The Subwoofer Is Inoperative
PINPOINT TEST L: THE SUBWOOFER IS INOPERATIVEL1-L3:
L3-L5:
L6-L7:
Normal Operation
The subwoofer speaker is powered by a separate subwoofer amplifier. The START input circuit, 174 (GY/BK), carries out two functions: to turn on the subwoofer amplifier, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then reduces the audio output signal to the subwoofer amplifier. The subwoofer amplifier receives power on circuit 720 (RD/YE) and ground on circuit 694 (BK/LG). Audio signals are received by the audio unit through circuits 169 (LG/BK) and 172 (LB/RD).
Possible Causes
- circuit 720 (RD/YE) open
- circuit 174 (GY/BK) open, short to power, or short to ground
- circuit 169 (LG/BK) open, short to power, or short to ground
- circuit 172 (LB/RD) open, short to power, or short to ground
- circuit 694 (BK/LG) open
- subwoofer amplifier
- subwoofer
- audio unit