please help diagnose my SID chip

[thatguy]

I have a Commodore 64C (new motherboard). The SID chip is an 8580, made in 1988.

 

I have tried running the Plogue SID benchmark (http://ploguechipsounds.blogspot.dk/2010/05/one-page-basic-sid-benchmark.html) and my chip doesn't really sound like any of the reference audio files. I have to really crank the volume to even hear the sweeps and there's a low-pitched tone during the pitch sweeps. The filter sweeps are very faint.

 

I tried loading up International Karate. I can hear the music in the background, but it's very quiet. The sound effects (punches, etc.), however, seem to be at normal volume.

 

What does this tell you about my chip?

[Hawkeye]

It might have broken filters, but it would also be possible, that your C64 has some problems on the audio output circuit. Do you have a fully working 8580, that sounds good in your C64?

 

Many greets,

Peter

[thatguy]

I see. Well, I hope it's the audio circuit then. I was planning on using this chip in my (still unassembled) sammichSID.

 

Unfortunately, I don't have a fully working 8580 at the moment, but I'll have to buy one at some point since I need two for the sammichSID, obviously. I plan on running the SID benchmark before buying, so that I know I'll be getting a fully working SID.

 

I do have a brown C64 with a 6581, however, but I don't have the power supply for the brown C64. Is it safe to use the power supply from the newer C64 to power the old one? Don't worry, I don't plan on using two mismatched SIDs in my sammichSID.

[Hawkeye]

You can safely test the other C64 - the power supplies are identical. Be aware, that the 6581 needs 12V though (and you just cannot swap the SID chips between different C64 models).

 

Many greets,

Peter

[thatguy]

Thanks. Turns out the brown one is broken. I only get the blue screen and the border, no "BASIC" text, but I guess the SID chip might still be OK.

[thatguy]

Update: the SID turned out to be fine :)