I wish I could find a schematic but no luck so far - it does sound like it may be a simple component failure. Do you know if C7 is a filter cap or a decoupling cap? Tracking the signal back shouldn't be too hard with an oscilloscope and should give an idea if the issue is in the analog signal path or in the power/digital part. You just have to have or know someone with a scope...
On Sat, Aug 25, 2018 at 10:34 PM John-Robert La Porta < [email protected]> wrote: > Fudgecicles...I think I have shorted out my sound circuitry. Part of the > monitor output board touched one of the capacitors briefly in the sound > area. Now, the sound comes on on startup, and then disappears. I can > briefly short out across capacitor C7, and that makes the sound work for 3 > or so seconds, then fade out into static. If I repeatedly short it > on-off-on-off, etc, I can keep it going. However, keeping it shorted > doesn't help either. Seems like some capacitor somewhere may have been > shot. In brief, I have no idea, and unless someone is an absolute genius > with this...I need a new Quadra/Performa 63x motherboard. > > Does anyone have a spare or one that they would be willing to part with? > > -- > -- > ----- > You received this message because you are a member of the Vintage Macs > group. > The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > To leave this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/vintage-macs > > Support for older Macs: http://lowendmac.com/services/ > --- > You received this message because you are subscribed to the Google Groups > "Vintage Macs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
