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Talon
Account closed
Registered: May 2007
Posts: 11 |
Replacing sid/vic, version question
Aloha!
I currently have four C64 (of which one is a C64c) in my home. Yesterday, the last functional one broke (only shows a reset-y screen with no characters on it on startup).
The C64c's keyboard is broken, but I connected one of the other keyboards to it so that works. But the 6581 in it seems to be dead too!
Do you guys know if it would work stealing a 6581 from one of the older machines? I remember one of them sounding especially nice - it has a 6581 from mid 1983 in it (the so called "6581, revision 3"). The C64c has an 6581 revision 5 in it (8580R5). If it's an OK operation it will just have made the C64c sound better :)
Apart from that, have anyone of you experienced the failure I described at the top (unresponsive screen without text, looks like 38 columns or so)?
Maybe I could just as well steal a working vic chip instead, and fix that machine? Or does it seem more of a CPU thing? Crappy error description from me I suppose - maybe you can ask me some good questions about it if you care to help.
I haven't been much of a hardware guy till now, but since I now have 4 malfunctioning vintage computers it might be time to get a soldering gun and have a go :)
Best
/T |
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Devia
Registered: Oct 2004
Posts: 401 |
You cannot use the 6581 from your old C64 in a C64c with 8580 chip in it, so please do NOT attempt this.
You can also not use the VIC from your C64c in your old C64 without the risk of frying it (it will work at first, but who knows for how long)
In reality, I haven't seen an unfixable c64 yet, but it does require knowledge and some skill to do it in most cases.
Where in the world are you located, Talon?
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Talon
Account closed
Registered: May 2007
Posts: 11 |
Great info, thanks!
I live in Stockholm, Sweden.
/T |
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ready.
Registered: Feb 2003
Posts: 441 |
about display problem, if you get the usual light blue & blue colors at start up, VIC is 99% ok, the problem might be one of the CIA chips or both (6526), or even a damaged RAM chip. |
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Devia
Registered: Oct 2004
Posts: 401 |
Best choice would be to have one of the guys from Stockholm who are going to LCP bring your HW to LCP and let Mogwai fix it.
From 3 broken breadbins, chances are two can be fixed.
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Devia
Registered: Oct 2004
Posts: 401 |
uhm.. just read your post again...
So you have a functioning C64c with no sound?
Check the fuse in the machine!
Check the fuses in the powersupply, if it's the old model powersupply with fuses in them. Alternatively, try a different powersupply.
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taper
Registered: Dec 2001
Posts: 119 |
I agree with Devia. At LCP (www.lcp.c64.org) in a few days, Mogwai will attempt to repair broken hardware, just as he has done prvious years with great result.
Bring your machines there, or give them to someone from Stockholm who will attend.
That is, unless it was the fuse that needed to be replaced afterall! :) |
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taper
Registered: Dec 2001
Posts: 119 |
Devia: By the way, I ofcourse knew that the 6581 and 8580 is not interchangable because of voltage differences.
But, could you elaborate about VIC chips not being interchangeable aswell? This is news to me. How come this is the case? Do you mean the really old cheramic VIC's, or also the plastic ones? |
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Devia
Registered: Oct 2004
Posts: 401 |
ARRGH!!! I wrote a shitlong post and it got lost on submission :(
shorter version:
Old VIC-II (6569/6567) needs +12 VDD on pin 13.
New VIC-II (8565/8562) needs +5V VDD on pin 13.
Old VIC will work perfectly in new C64, but without video output, which I presume most people would want ;-)
New VIC in old C64 will work perfectly too, but you'd be supplying it with 7V more than it was designed for. There is a chance that C= thought about this and actually implemented some sort of voltage regulation or whatever, but until someone with the right skillset takes a closer look at the hires die photos of the new VIC-II and can say that this is the case, I would not risk it on other peoples behalf.
Personally I have had an 8565 running in an old C64 for a couple of days without any issues.
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Devia
Registered: Oct 2004
Posts: 401 |
same thing goes for SID, btw.. New SID in old C64 will work, but sound really awful due to the 3V overvoltage ;-)
haven't tried old sid in new machine, they are too precious ,-) ..but I suspect that they would either be silent or sound like crap.
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Talon
Account closed
Registered: May 2007
Posts: 11 |
Quoting ready.about display problem, if you get the usual light blue & blue colors at start up, VIC is 99% ok, the problem might be one of the CIA chips or both (6526), or even a damaged RAM chip.
Yeah the blue/lt. blue screen, blank, and in what looks like 38 column mode.
Thanks for the pointer here.
/T |
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