Got a JL Audio in for repair. The amp powers on. Power led and low ohm led are lit. Distortion, screeching and high pitch whine in the output. Sounds like the old dial up modems. Does it with no signal input also. I read there should be about 60 volts to ground on the speaker leads. I'm getting about 115 volts on the speaker leads. Checked the resistors in the output filter circuit. No broken leads and they check fine. Any ideas? Thanks!
Hi Perry, upon closer inspection, I've found four broken legs. Two on diodes in the bridge circuit and two on mosfets. Replaced these and now have the amp running. I suspect the amp has been mounted to a speaker box. Although the owner claims it wasn't. I will double check all mosfets and burn the amp in. Thanks for your help.
Perry, would you recommend changing all the outputs with the same date code? Or is this amp forgiving in that regard?