Typically we did not have a revision of a chip number make it incompatible with other chips, so,me slight exceptions where constants needed tweaking. If you have one it is worth a swap out I would think as even if it isn’t 100% compatible it should still be loud if the pcb is working. If you have a scope there are some places you could test voltage and signal, even a low bandwidth scope due to it being audio. Bil Herd -----Original Message----- From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of Ed Johnson Sent: Monday, January 30, 2012 10:12 PM To: firstname.lastname@example.org Subject: RE: LOW VOLUME SOUND C64c I see the 6581 uses a 12 volt supply - the 8580, a nine volt supply But does the revision on the 8580 SID matter? Best regards, Ed Johnson -----Original Message----- From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of Marko Mäkelä Sent: Monday, January 30, 2012 2:02 AM To: email@example.com Subject: Re: LOW VOLUME SOUND C64c On Sun, Jan 29, 2012 at 04:43:51PM -0500, Ed Johnson wrote: >I checked the fuse inside. It was good. >The board is a PCB ASSY #252311 REV 3 > >I has a very sharp clear video picture. Better than the older bread box >version I tested the power supply with. > >Any other ideas? Could the SID chip be damaged? Over 20 years ago, I damaged a SID chip in an old-style C64 (+12V VIC and SID) by hot-plugging the audio output to a stereo receiver that was also hooked to an antenna amplifier that may have been powered from a different mains voltage phase. This could have caused a ground current. I cannot remember clearly, but I think that the audio was very quiet after the incident. Replacing the SID chip cured it. Marko Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2012-01-31 04:00:35
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