C64 sound problems

[David Betz]

On Jul 10, 2009, at 2:43 PM, David Betz wrote:

>> are you using the correct cable plugged into the correct place?
>> this is usually the biggest cause.
>> sound was mono, and you need the proper wiring, and your tv/etc may  
>> only accept
>> mono sound on a specific input
>
> One thing I've been wondering about is if this could be caused by  
> problems with the 12v supply feeding the SID. Is there anything else  
> in the C64 that uses that voltage or is it just for the SID?

I finally got around to checking the 12v supply in my C64 and it seems  
to be working. I also verified that 12v is getting to the VDD pin on  
the SID chip so lack of 12v is not my problem. One thing I noticed  
that I thought rather strange was that the VCC pin on the SID reads  
5.27v but the output of the 5v regulator is correct. Is there a reason  
why the VCC at the SID would be higher? Could this be causing a problem?