In part 1, I told the story of how I acquired my arcade cabinet and the unwanted guests we had hidden inside. In this post, I will go over my discoveries after spending a day with the (unworking) cab.
I woke up early Saturday morning so I could get started before it got too hot (it still smells bad from having the dead rat in it, so we're keeping it in the carport to air out). I plugged in the cab and the speakers made a crackling sound for a few seconds and then went silent. There were no sounds and the monitor did not turn on.
So, I began to follow the excellent instructions on the Fix your Pac-Man website. I started with the fuses. Here's a picture of one of the fuse blocks.
This is definitely a problem. I took each fuse out to check for continuity. They were all good except for one of the 1 amp fuses. However, they were corroded and were not making good contact. I spent the afternoon acquiring new fuses. When I got back from our lunch trip, I put the new fuses into the machine. Still no change.
So I started checking voltages and various points. I started with the obvious, the power cord. It measured ~115v, so that's good. I then measured the voltage going into the monitor (at the molex connector). It was ~5v. Not good. It's supposed to be ~115. I then started backtracking to the isolation transformer. I measured the voltage on the top pins (the ones that feed the monitor) and they were the same ~5v. So I checked the bottom pins (going to the AC line filter). Nope, still bad.
Next, I checked the voltage going into the line filter. Good. Coming out of the line filter was a different story. It's supposed to be ~115v. It wasn't. So, I have isolated my issues to a bad line filter.
Rather than simply replace the line filter and continue on, I'm going to do a total rebuild of the power supply based on this excellent article on arcadecontrols.com. While I'm at it, I'm going to rewire the cabinet for a JAMMA interface. This will allow me to use JAMMA boards in the cabinet.