Response from Jonathan: Michael,

Thank you for the kind words. Glad you have found our website useful. Now, let’s get to your questions:

1.) I am assuming that your Donkey Kong cabinet has a Sanyo 20EZ monitor in it. This is the most common monitor for Nintendo upright cabinets. If you want to be sure, compare your monitor chassis to this image and see if it looks similar. If you do indeed have a Sanyo 20EZ, start off your repair by checking to make sure that test switch SW301 on your monitor chassis is in the Normal position and not the Service position. This can cause issues like this. If that doesn’t work then you could have some problems with the vertical section of your monitor chassis. Make sure you look specifically at transistors TR402 and TR403 and the parts around them for any component failure. It might also be a good idea to install a cap kit while you’ve got the chassis out as this can fix a multitude of issues especially with this particular model of monitor.

2.) I’ve seen this before. You might try reseating/pushing on the ROM chips at locations 6E and 6F as this can cause this issue. If that doesn’t work, you may need to replace these ROM chips entirely. Highly recommend checking out the Lawnmowerman’s Pac-man Website if you haven’t already as it has lots of great information on Pac Man boards. There used to be a great page on Pacman Troubleshooting on the arcadegameover.com site. It looks like the site has been taken down but archive.org still has an image of it if you want to check it out. Both those sites are great resources for repairing Pac Man board issues.

3.) Hmm, this one is interesting. We would probably start off by letting the board get to the flashing state you are describing and check the voltage with our multimeter at that time. This would tell us if the issue was caused by the board or the power supply. Obviously if the voltage is higher than normal at this point then we’re probably having a power supply issue of some sort. Otherwise we’re probably leaning more towards a board issue. The power supplies are pretty easy to rebuild but the board can be tricky. It could be a problem with your CPU chip but that would be just a guess on my part. There’s a lot of great information on the Nintendo Vs system on the John’s Arcade website including a power supply manual and lots of information on how the board works. I would start looking through his content if you continue to have problems.

Hope that helps. Thank you for your questions and good luck with your repairs.