Nakamichi OMS-7/Kyocera DA-910 intermitent output. any ideas?

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Just picked up a very clean Kyocera DA-910 , which is basically a Nakamichi OMS-7 in a fancy case. Some p/s upgrades , but same dac board; dual TDA-1540's. Also a similiar , but potted , output circuit. I changed the belt on the transport and it seems to read most of my cd's very well; just some problems with the rough ones. About a half hour of being proud of myself for fixing it so easily , the right channel became distorted and eventually muted. Since I have another dac board from an OMS-5 , I swapped it out. Played fine for 15 minutes , then the same issue. My guess is the output board is the problem , but it seems to work again if I unplug the power to it , with cd playing , and reconnect it. But only for a short time. Anyone familiar with these(Nak/Kyo)?
 
Sadly, you have the classic symptom of a failure within that sealed output module. On the Nak OMS-7, this is a repairable circuit, but the DA-910 has the whole thing potted in epoxy or tar(can't recall which). Your only option is to either build a new output stage of some design, or replicate/steal the output stage of an OMS-7. If the potting material is tar or something else not too high temp, you might be able to bake it out, but I've never tried that on one of those.
 
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