i wonder how many c64's and sids have been thrown away due to the operator not realizing their machine isn't actually dead.. but a simple thing such as an oxidized socket has caused issues.. or simple power supply problems...

sad to think about really.

a simple way to test a SID chip if you happen to have Messiah, is to go into the test mode. you can test all 3 channels.

hmm... hadn't thought about that. Will check that thanks!

Hey rumpelfilter, check the internal blow fuse- it might be broken, which causes the sid to produce no sound, but still produce a clear picture- obvious thing to miss, and people always shout CAPS. As your SID still seems to be alive I'm guessing it'll be this.

back again on this subject. Since I was busy with other project I had left is aside for some time, but now I decided to see if I could find the problem with that C64C. I removed the SID, put it into the SammichSID and voilà! It works! Even better than the one I had installed (less noise). In fact, when the SID was still in the computer I had run a few tests with joysticks and pots to see if it was responding, and in fact it was...

So now my guess is that it's either some caps, os something else is broken. I could go on and change all the caps on the board, but I guess I'll just leave it at this, and sell it for some ridiculously low price... anybody interested?

As long as you put hem in a 100% working motherboard it should be OK.
I did the other way round: I had a C64 with no sound so I had the bright idea of putting another SID in it. It would still get no sound. I did it again. The problem was on the motherboard therefore I fried 3 SIDs in one afternoon. Yipee yay!

If you're comfortable with working with the ICs and have another C64 with sound that works, you can swap the ICs from their sockets.  I turned four dead C64s into two working ones in that way.

copy-paste would have been great for this!
thanks, I'll try this as well!

edit: typo

Some dude post it on lemon64, old fashion way of testing sid by typing fuckin code, it rocks:

To test voices:
10 FORL=54272TO54296:POKEL,0:NEXT:POKE54296,15:GOSUB60
20 POKEW,17:POKEA,9:POKEHF,15:POKELF,35:POKES,128:GOSUB50:GOSUB70
30 POKEW,17:POKEA,9:POKEHF,20:POKELF,40:POKES,128:GOSUB50:GOSUB80
40 POKEW,17:POKEA,9:POKEHF,25:POKELF,50:POKES,128:GOSUB50:GOTO10
50 FORX=1TO2000:NEXTX:RETURN
60 W=54276:A=54277:HF=54273:LF=54272:S=54278:RETURN
70 W=54283:A=54284:HF=54280:LF=54279:S=54285:RETURN
80 W=54290:A=54291:HF=54287:LF=54286:S=54292:RETURN

Test Filters (please take note of the +16 +32 and +64. This will need to be changed to test each):
Code:

10 poke54296,15+32 :rem filters:  +16=low-pass, +32=band-pass, +64=high-pass
20 forv=1to3:print:print"voice";v:forl=54272to54295:pokel,0:next
30 onvgosub80,90,100:pokehf,15:pokelf,35:pokehp,8:pokelp,0:pokea,9:pokes,128
40 pokew,65:poke54295,2^(v-1)+128:forp=0to1
50 forf=0to2047step9:gosub70:next:forf=2047to0step-9:gosub70:next:next:next
60 forl=54272to54296:pokel,0:next:end
70 printf;"{left} {up}":poke54294,f/8:poke54293,fand7:return
80 w=54276:a=54277:s=54278:hf=54273:lf=54272:hp=54275:lp=54274:return
90 w=54283:a=54284:s=54285:hf=54280:lf=54279:hp=54282:lp=54281:return
100 w=54290:a=54291:s=54292:hf=54287:lf=54286:hp=54289:lp=54288:return

Thanks a lot people!
I'll try some of this and in case report back!
Hannes

Yeah, that's happened to me. Still, it would give rumpelfilter an idea if the pots don't work.

I think the DAC or some other audio shit can stop working but still let the chip read the pots...

The SID is used to read analog data from the joystick ports. If you have a device (paddle, pot controller) that you could plug in and see if the SID talks to them, that would give you an idea if the SID is working.

Other than testing a known good SID, that's the only way I can think of!

I had loose Sid on sid2sid (fucked socket) which I eventually fried and whole C64 stopped working. Luckily i got about 15 spares
So maybe it is a resistor or something else.

Goto80 mentioned testing out the sid chip on a console with different versions of power supplies to check if it is really dead or not. Check his site for more information.

http://goto80.blipp.com/sid-chaos-paranoia

Sometimes capacitors fail, but when you get flat out no sound, it's probable that the chip is dead.