The amp biased correctly at about half way on the bias pot.
The resistance needed was 370 ohm.
I removed the jumper from q11 and the amp turns on as it should.
Audio sine waves look great through the amp at the output. I tested a few different frequencies from 40 hz to 15 kHz to be sure.
After about 2 hours of music playing through the amp at a good loud level with a 3 ohm 6x9 on each channel the amp was running about 96-97 degrees measured via ir thermometer on the output mosfets.
Thank you Perry Babin for all your help! I really appreciate it and the owner of the amp is thrilled!
The resistance needed was 370 ohm.
I removed the jumper from q11 and the amp turns on as it should.
Audio sine waves look great through the amp at the output. I tested a few different frequencies from 40 hz to 15 kHz to be sure.
After about 2 hours of music playing through the amp at a good loud level with a 3 ohm 6x9 on each channel the amp was running about 96-97 degrees measured via ir thermometer on the output mosfets.
Thank you Perry Babin for all your help! I really appreciate it and the owner of the amp is thrilled!
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You weren't running it hard enough for testing if you're repairing this for someone. In about 5 minutes, when running hard, it will be FAR too hot to touch.
Run it hard enough to get the temperature up to see if the bias holds at higher temperatures. If you don't want to run it harder, cover it with a towel to prevent it from cooling. Check the idle current about every 10 degrees. I'd suggest running it up to thermal shutdown when checking the bias.
Run it hard enough to get the temperature up to see if the bias holds at higher temperatures. If you don't want to run it harder, cover it with a towel to prevent it from cooling. Check the idle current about every 10 degrees. I'd suggest running it up to thermal shutdown when checking the bias.
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