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c0pperdragon / C64-Video-Enhancement

Component video modification for the C64 8-bit computer
MIT License
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C64 does not boot with VIC-II Adapter Board #86

Open Picornavirus opened 1 year ago

Picornavirus commented 1 year ago

Hi, i have encountered a strange problem with the adapter board (obtained the mod at VGP). I have installed the mod on a PAL ASSY 250407 Rev. B with a VICII 6569R1. In general my C64 runs without any problems. However, as soon as i install the adapter, the C64 does not boot and i get a black screen. The Dead Test Cardridge results in flashing 2 times. After the removal of the adapter the C64 works again without any hassels. Any idea what could possibly cause this symptom? Any suggestions how to troubleshoot (I have an oscilloscope)? Thanx in advance

c0pperdragon commented 1 year ago

I guess with "adapter", you just mean the small PCB that goes between the VIC and its socket. This should normally not interfere with the working of the computer at all, so something is broken here.

My guesses (in decreasing order of probability):

  1. The pins from the adapter to the socket are not making good contact. This can be due to pretty low quality of these sockets and because the adapter has quite short pins. For checking continuity, you would probably need to take the main board out of the C64. If this is ineed the problem you could fix it by putting a precision 40-pin socket in the C64 and put the adapter on top.
  2. There is some short between the pins of the adapter itself.
  3. The voltage regulator on the adapter is broken. I am not totally sure if this would indeed cause the signals to be corrupted, but you can check nevertheless if the 3.3 volts are generated.