I posted 7 years ago here with the exact same issue. Got the amp serviced locally and they fixed it (original post attached below)... They didnt tell me what happened, except that the amp got recapped completely during service, and its been working good until a few months ago.
Same issue is back. You flip the power switch ON, power led turns ON... no sound output. Flip it OFF and ON about 10-20x and the sound comes back to the speakers and the speaker relays inside the amp click.
Now, no more relay click after cycling for 100x times.
I opened it up and see the Caps that have been replaced and I found a blown 1k 1/2W resistor on the cap board, where the transformer wires go in. I can clip the resistor and and solder in a new 1k resistor but just curious why these resistors blow, in case it happens again. Or what that resistor does.
Also anything else I can check on the board while i’m in there?
Ill attach pics and schematic of a Fosgate 4200 amp (cant find the 4100 online), and my original post!
Thanks for any help or advice
P.S. I have another Fosgate 4100 that has a fuzzy left channel, another issue,.. But i can use parts from that amp or check anything from reference from it too.https://imgur.com/a/4d1hjCchttps://imgur.com/a/K5LD9vdhttps://imgur.com/a/A1KLm3Mhttps://imgur.com/a/5mXxZAmhttps://imgur.com/a/07852RQ