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Broken C64
https://retrohackers.org/viewtopic.php?f=1&t=346		 Page 1 of 1
Author:  janno [ Wed Feb 20, 2008 9:38 pm ]
Post subject:  Broken C64
Hello all,

I have faulty C64 :(. When I start my Commodore I see this picture:
Image .

Can anyone suggest, what's wrong with my computer?

Thanks in advance,
Janno
Author:  MagerValp [ Wed Feb 20, 2008 10:01 pm ]
Post subject: 
U17 PLA is a pretty good guess:

http://personalpages.tds.net/~rcarlsen/cbm/c64-ic.txt
Author:  mareLock [ Wed May 13, 2009 5:16 pm ]
Post subject:  Re: Broken C64
i think it looks allright :D
Author:  RaveGuru [ Thu May 14, 2009 10:36 am ]
Post subject:  Re: Broken C64
Check if the computer responds on blind commands. Try LOAD "$",8 and see if the diskdrive starts spinning. If so it's probably a bad VIC chip. Could also be bad RAM or ROM. Touch all the chips to see if anyone is unusually hot (SID and PLA normally runs hot but you shouldn't burn your fingers)
Author:  janno [ Thu May 14, 2009 12:15 pm ]
Post subject:  Re: Broken C64
RaveGuru wrote:
Check if the computer responds on blind commands. Try LOAD "$",8 and see if the diskdrive starts spinning. If so it's probably a bad VIC chip. Could also be bad RAM or ROM. Touch all the chips to see if anyone is unusually hot (SID and PLA normally runs hot but you shouldn't burn your fingers)

Thanks, I'll do that.
I replaced the U17, but problem still remained. So it has to be something else.
Author:  mistermsk [ Thu Jul 02, 2009 5:01 pm ]
Post subject:  Re: Broken C64
U16 CD4066 (generic CMOS quad bilateral switch)
Color problems such as random color "checkerboard" pattern on screen
or no color.


Looks like the chip at U16 (MOS CD4066). Might not be but it kinda' sounds like what your picture looks like.
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