derbiangames@gmail.com wrote on 07. January 2016:   
   >   
   > I have a '83 breadbin C64 that glitches in one particular demo called   
   > "Parts" (http://csdb.dk/release/?id=11689). It always happens during   
   > the first part of the demo (intro text / vector buildings). Either   
   > short flashes of garbage characters on the screen, or sometimes the   
   > graphics completely mess up and the demo freezes, accompanied by an   
   > abnormal sound.   
   >   
   > The strange thing is, I have run 100s of different demos/games on this   
   > machine and this is the ONLY one that doesn't work properly.   
   >   
   > I've already ruled out the following:   
   >   
   > -Disk/drive problems (tested with a known working drive, and another floppy)   
   >   
   > -VSP problems (the VSP test shows no problems on this machine. Another   
   > C64 I have DOES have VSP problems but it has no problems running this   
   > particular demo).   
   >   
   > -Faulty PSU (tested with another one, no change)   
   >   
   > -Tested with another breadbin, same cables and equipment -> no glitch   
   >   
   > -Both breadbins are PAL models   
   >   
   > It's not a big issue since it only affects this one demo, but I'd still   
   > like to solve this mystery. Maybe some tiny timing issue that only   
   > affects the most sensitive programs? RAM, CIA, PLA, SID and VIC are   
   > socketed, and some of them have had contact problems in the past. But   
   > it's unlikely that would affect just ONE program. And since some of the   
   > sockets are already pretty worn out, I'd prefer not to put more stress   
   > on them unless needed.   
      
   [...]   
      
   Can't help. Just mention when I got an Amiga 500 in 1989 with a similar   
   problem. I had to return the first and also its replacement. Although   
   both worked fine they both wouldn't play a specific demo. I really had a   
   hard time to return the second one because the clerk couldn't believe two   
   Amigas sold to me wouldn't work.   
      
   Anyway, got a third and that would play the demo. May be it was from a   
   different plant or used a chip from a different manufacturer responsible   
   for the problem.   
      
   Oh. And the very first Commodore 64 I bought late 1983 just had garbage   
   on the screen when just turning on. Had it replaced and that one served   
   me well for the next 6 years until I sold it.   
   --   
   Andreas   
      
   I use a Unix based operating system, which means I get laid almost as often   
   as I have to reboot my computer.   
      
   --- SoupGate-Win32 v1.05   
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