Test H: The Subwoofer Is Inoperative

PINPOINT TEST H: THE SUBWOOFER IS INOPERATIVE

H1-H2:

H2-H4:

H5-H6:

H7-H8:

H9-H11:

Normal Operation
The subwoofer speaker is powered from a separate subwoofer amplifier. The enable/clip circuit, 174 (GY/BK), carries out 2 functions: to turn on the subwoofer amplifier, and to indicate to the audio control unit when the subwoofer output distortion signal reaches a damaging level. The audio control unit then reduces the audio output signal to the subwoofer amplifier. The subwoofer amplifier receives voltage on circuit 1678 (WH/VT) and ground on circuit 1204 (BK/OG).

Possible Causes
- circuit 720 (RD/YE) open
- circuit 174 (GY/BK) open or short to ground
- circuit 176 (PK/LG) open or short to ground
- circuit 179 (OG/RD) open or short to ground
- circuit 1204 (BK/OG) open
- subwoofer amplifier
- subwoofer
- audio control unit