Audiobahn A8002V overheating

[blabay 10+ year member]

I'm looking at a A8002V for a friend and it has a strange problem. It works fine for a few minutes at higher levels and then goes into protect. The less you push it, the longer it runs. I know its thermaling out, but I can't figure out why. I ran it on the bench bridged with a 4 ohm load and a 100Hz sinewave at less than 10 watts and it only ran for about 15 minutes. The fan is working and it doesn't overheat with no signal, so the bias seems ok. Anyway, I'd love to get a schematic for it if anyone has one. Any advice on the problem would also be greatly appreciated.

Thanks

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[Timmothy Web 10+ year member]

do u know if the output side or the power supply is over heating?

 

[Imtjnotu 5,000+ posts]

Where are you gain set t and what is u voltage like while playing

 

[blabay 10+ year member]

The power supply is cool relative to the outputs. Its not too hot to touch, but pretty warm. The power supply I'm using isn't very big, and I can't get much power out of the amp before the supply sags. Under the test I mentioned above, the power supply was at about 13v.

One curious thing, I don't see any thermal sensing components or bias transistors mounted to the heatsink. How does its thermal management work?