rockford fosgate p4004

[mike49504]

Im working on this amp and something strange is going on . If you have the switch on two channel input all 4 channels work fine. Then if you switch it to 4 channel input only 3 channels work -- left front channel is dead. Wondering what might cause this??

Any help would greatly be appericated

[Perry Babin]

Email Rockford for the schematic diagram.

A defective switch, RCA jack or op-amp could cause it. The switch or jack would likely be intermittent. A defective op-amp may get significantly hotter than other similar op-amps (those with the same part numbers). You can also compare the inverting input to the non-inverting input on each op-amp used for audio. Those two inputs (for each half of each individual op-amp) should have essentially the same voltage (±0.020mv DC -- approximately).

[mike49504]

Ok i found that the rca jack was loose resolderd it. Also theres a burnt trace in the power supply section But the amp still works it. It popped the trace on both sides of the board near the caps Wondering if you might know why this is??

[Perry Babin]

I don't know what caused it to burn. Several people have emailed me with similar problems. Generally, they repair the trace and the amp works. If you determine what caused it, post it here.