I've been working on an Aiwa HS-J9. Two of the problems were weak volume, and only very faint audio from the right channel. Eventually I narrowed the channel problem down to the equalizer. But I couldn't locate the problem deeper than that. I suspect the graphite surfaces the equalizer tabs slide on are damaged, but they look ok. Checking voltages, resistors and capacitors on the equalizer board led nowhere. Before, I advised bypassing the equalizer by shorting the Lin and Lout, and Rin and Rout terminals for the equalizer flat ribbon cable. But that didn't fix anything on this one. Instead, I connected the Dolby Out, R and L, to the Rin and Lin connectors on the volume control. This restored both full volume and the R channel. These equalizers are delicate, and impossible to buy as spare parts. So far most of my attempts to fix them have failed. I'm considering using conductive paint to restore the graphite surfaces. Not having an equalizer function is not a big deal in functionality, since few players like this have them. Especially if everything else works.
