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Onkyo Receiver swtiching between A and B speakers

Onkyo TX-DS747. Started switching from speaker A to speaker B, and from Speaker B on to Speaker B off, and same with A, off and on over time. Now it is all the time. Started with just A, then we wired our speakers to B, then it started later with B, now it is with both.
I thought maybe it was front panel switches. Took unit apart, looked around, pulled front panel, looked at that, and it looks like those little switches would last nearly forever. So, when the unit is plugged in, I can hear the clicking of the switching happening. You can trace this to two parts, identical, on a board near the huge heat sink in the unit. The parts are DEC parts- DG2SU- and lo and behold, Onkyo and DEC don't even recognize those part numbers any more. As in, they can't even order them, bring them up in their systems, etc...
So I don't know what to do. I was going to try replacing the switches by unsoldering the wave solder on the bottom of the board and putting in new one's to try that, but I can't even get parts????
Does anyone have any insight on how to fix, find parts, or work around this problem?
The parts say on them 24vDC, 2A 125vAC. I would assume the 24v is the circuit power from the front switches; and the 125vAC is the current to the speaker channel? Anyway- how can I fix this?

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Any help on this would be appreciated. I have the same problem now with my 727.

Posted on Dec 05, 2010


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