Ms. Pac-Man Upright -- Fuses Questions

SpellboundLogic

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What was happening:
The original issue I was troubleshooting is that the game would suddenly freeze with a spill of random characters and glyphs. The board was serviced and played fine in another machine, so I'm content to believe the flaw is somewhere on the transformer block.

When the glitch would happen:
Sometimes on the attract screen, sometimes many screens into the game. It seemed like a voltage drop, so I did some research here and noticed that almost everyone recommended replacing the fuses and fuse holders. While I didn't replace the fuse holders, I cleaned the clasps for all of them with 800 grit sandpaper and sprayed them with DeOxit. Connections appear to be tight, making proper contact around the fuses. Deoxit on all molex connectors, edge connector and wiring harness.

The outcome thus far:
This seems to have fixed the freeze issue, but I'm concerned about fuses getting very hot. Here is what I've been seeing:
  • I noticed that the 12v fuse for the marquee light was getting hot very quickly. It was a 1.5a slow blow fuse and some instructions have said that newer revisions used a 2a slow blow fuse. I'm pretty sure the fuse label, though tattered and dirty, indicates a 2a fuse. When I replaced it with a 2a, it no longer ran hot. In doing so, did I risk other components down circuit in the event of a current overdraw? Or was this the correct fuse to work with?

  • On the 7v 5a fuse next to the green wire which goes to the logic board, I noticed it's still drawing a lot of heat. After a minute, it starts to get really hot in the middle of the glass. Is this normal or is it a sign of excess heat dissipation and current overdraw? I paid special attention to the fuse holder for this and sanded it with a few passes.

  • Several ICs on the game board were getting pretty warm to the touch. Is that normal?
 
Components on the game board can get warm or even hot to the touch depending on what it is. But it shouldn't burn you.

If you haven't replaced the fuse holders, do yourself a favor and just do that. The originals are terrible and will cause you all sorts of headaches. Make sure your card edge on the game board and card edge connector is clean and is not tarnished. That can cause voltage drop.

To be honest, I really don't like the AC power setup with pacman boards. Even doing everything right can still result in a burnt board card edge. It can be a fight.
 
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