lisalover1 Posted August 11, 2013 Share Posted August 11, 2013 I got a C64 a while back that I have never been able to get working quite right. The AV output in particular seems to be an issue. When I have the computer plugged into my TV via RF, everything looks fine, and I am able to load up software just fine, except that there is no sound coming out of the speakers whatsoever. I also have a mono composite AV cable that I use for my Master System that I tried for my C64, and depending on the TV I plug it into, it either makes an incessant high-pitched screeching noise, or displays scrolling black bars across all the TV's inputs. I tried opening up the C64 and giving it a good cleaning, and even re-seated the SID chip for good measure, but to no avail. Any ideas on what to do? Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/ Share on other sites More sharing options...
lisalover1 Posted August 11, 2013 Author Share Posted August 11, 2013 No ideas? Does anyone have a spare SID I could buy off of them? Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808501 Share on other sites More sharing options...
R.Cade Posted August 11, 2013 Share Posted August 11, 2013 (edited) The Master System AV cable has a different pinout than the C64 one, even though the plug may fit. You likely have blown the SID/sound chip by plugging it in this way. Edited August 11, 2013 by R.Cade Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808506 Share on other sites More sharing options...
lisalover1 Posted August 11, 2013 Author Share Posted August 11, 2013 The Master System AV cable has a different pinout than the C64 one, even though the plug may fit. You likely have blown the SID/sound chip by plugging it in this way. ...Shit, I just assumed it was a standard connection, given that I've seen the same input on multiple devices. Now I really do need a new SID chip. Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808545 Share on other sites More sharing options...
R.Cade Posted August 11, 2013 Share Posted August 11, 2013 Yeah, fortunately (unfortunately for you) one of those pins is an unprotected input into the analog portion of the chip. This can be used to run filters and other effects on the signal. Hooking it to a TV (escpecially while 64 is powered on) can blow it. Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808549 Share on other sites More sharing options...
RickR Posted August 11, 2013 Share Posted August 11, 2013 If the RF still works, you blew nothing up using the wrong cable. C64's, in my experience, are hard to find completely working. You may or may not need a new SID chip, but you may have better luck getting another C64. If that one doesn't work, then you'll have parts to mix and match between the two to hopefully get one working. Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808550 Share on other sites More sharing options...
lisalover1 Posted August 11, 2013 Author Share Posted August 11, 2013 If the RF still works, you blew nothing up using the wrong cable. C64's, in my experience, are hard to find completely working. You may or may not need a new SID chip, but you may have better luck getting another C64. If that one doesn't work, then you'll have parts to mix and match between the two to hopefully get one working. Well, C64's are pretty pricey, so I think I'd like to try and find a SID chip alone first. :S Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808576 Share on other sites More sharing options...
Osgeld Posted August 11, 2013 Share Posted August 11, 2013 I think it would be more prudent to get the correct cable and see if you blew anything before you go shotgunning this using up as much hardware as possible ... I am not a 64 expert but the outputs on the back of the TV is going to put out at most 1v and the inputs are not going to measure anything, making it interesting that one could blow anything with a high impedance analog input inside the device Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808631 Share on other sites More sharing options...
R.Cade Posted August 11, 2013 Share Posted August 11, 2013 It happens from fumbling with the cables while swapping them around to figure out which is which. If you short that ring to tip, it's blown. Sure, it's possible this didn't happen. Get a C64 video cable and try it out. Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808675 Share on other sites More sharing options...
lisalover1 Posted August 11, 2013 Author Share Posted August 11, 2013 It happens from fumbling with the cables while swapping them around to figure out which is which. If you short that ring to tip, it's blown. Sure, it's possible this didn't happen. Get a C64 video cable and try it out. So you're saying that just because the RF isn't outputting audio doesn't mean that the AV port won't? Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808786 Share on other sites More sharing options...
R.Cade Posted August 11, 2013 Share Posted August 11, 2013 So you're saying that just because the RF isn't outputting audio doesn't mean that the AV port won't? Very slim chance, but you'll want the right cable anyway. Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2808790 Share on other sites More sharing options...
thegamezmaster Posted September 2, 2013 Share Posted September 2, 2013 I've got a C64C with no sound. What's weird is there is no voltage coming in on pin 28, I think that's right, but everything from what I've read that shouldn't work does. It's one of the newer motheroards too. Wish I could figure out. Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2822584 Share on other sites More sharing options...
bvenneker Posted December 11, 2013 Share Posted December 11, 2013 If your commodore 64 with new style motherboard has no sound, it is very likely just the internal fuse!If the fuse is broken on a new motherboard, your tape interface will not work AND there is no sound, but loading a game from disk is no problem.On an old motherboard, if the fuse is broken, the power led comes on but there is no image on tv.How to identify OLD or NEW motherboards: On the old motherboard the fuse is placed horizontal (left to right)On a NEW motherboard the fuse is placed vertical (top to bottom) Quote Link to comment https://forums.atariage.com/topic/215424-c64-sound-issues/#findComment-2883506 Share on other sites More sharing options...
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