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Gentlemen, I managed to burn 2 front channels on my Harman Kardon AVR-255 receiver. The woofers of the speakers are burnt as well.
I found the scheme, but don't really understand a lot.
I replaced the Q658 and Q652 just to find out that it did not fix the problem. I checked those transistors with R-tester, they seem Ok.
Maybe someone could give me a hint what should I try to replace next. Those channels still can produce some sound, but it has lower volume and very noisy, compared to the working channels. When I switch the receiver on, it usually switches into protected mode immediately. After about 10 tries it starts normally.
Any help is appreciated, as the only way I have is to remove transistors one by one and check them with my multi-meter.
PS. Not sure you can see the scheme, it gets resized on small screens for some reasons
scheme
I found the scheme, but don't really understand a lot.
I replaced the Q658 and Q652 just to find out that it did not fix the problem. I checked those transistors with R-tester, they seem Ok.
Maybe someone could give me a hint what should I try to replace next. Those channels still can produce some sound, but it has lower volume and very noisy, compared to the working channels. When I switch the receiver on, it usually switches into protected mode immediately. After about 10 tries it starts normally.
Any help is appreciated, as the only way I have is to remove transistors one by one and check them with my multi-meter.
PS. Not sure you can see the scheme, it gets resized on small screens for some reasons
scheme
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