Hello,
I have some basic understanding of circuits but I'm in the deep end on this. I'm trying to determine if it's feasible or even possible to repair an old amp. I noticed that the right speaker in my car didn't work suddenly, and I traced the fault to the amp. After measuring the faulty output, it seems it has reversed it's polarity, the marked positive terminal is actually negative. The voltage is roughly the same on both channels. Faulty channel does output sound but at a very low level. No other fault indications or blown fuses, however it did start popping a bit on startup for a few days before that channel failed.
It's a 2-channel amp with bridged output possibility, CLS CA21 if it matters. I took it apart but no clear signs of destruction, just some flux residue that I cleaned up. I attached few pictures of the board and the channel output transformers/transistors/mosfets on it, as I thought some of those might be faulty. I didn't desolder them yet for testing since I wanted to ask for advice first. Maybe something wrong on the bridging circuit?
I've identified these components per channel:
4x
FQP50N06 Mosfet
2x
2SA1694 & 2SC4467 Power transistors
FMG22S + 22R recovery rectifier diodes(?) - why would you need these with dc input power? Related to bridging?
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