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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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In Reply to: RE: Adcom GFA-555II repair: just how unstable are these 2SA1210's? posted by EchoWars on September 27, 2007 at 03:00:26:
The 1210's that were in there, along with all the other parts, look to have been original to the amp (original solder, parts markings all matched, etc). I got the replacements from MCM. The packaging says they are Sanyo parts. IIRC, neither Digi-Key nor Newark carried them, and B&D didn't carry enough of the other things I needed. They're failure seemed to me to be a potential issues because I had seen a second one, again this was in the other channel and in a differnt position in the circuit, fail so soon after replacing an already bad one, and because a number of Google hits about this amp turn up discussions of this same failure mode.
Do people really bother making fakes of 80 cent parts?
As for the bias, I think I'll need to open 'er back up and check again. I had adjusted the repaired channel (left) to match the right channel, which was initially working. The right channel was dropping 6mV across its emitter resistors, so that's what I adjusted to. Sounds like it was biased a bit low already, or had drifted low.
Thanks again for the help,
Paul
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Follow Ups
- Thanks for the info... - SQLGuy 07:20:31 09/27/07 (1)
- Fake Parts ? - djk 03:16:11 09/29/07 (0)
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