No power to Pac-Man monitor

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    • No power to Pac-Man monitor

      I just acquired my first arcade cabinet, a 1980 Pac-Man cocktail cabinet. However, when I plug it in, I only hear some crackling from the speaker for a few seconds and then silence. There's no picture on the monitor or sounds coming from the game. I measured the voltage on the power cable and it's 120v (my house is a little on the high side). I replaced all of the fuses and checked the voltage on the monitor cable. It was less than 5v. I then checked the voltage on the monitor transformer and I'm not getting the expected 115v.

      I'd like to do a power supply conversion, but all of them tap the monitor voltage.

      I've studied the schematic in the manual and I think it may have something to do with the filter, but I'm not sure what pin is what on that component.

      I am an electronics hobbyist, not a professional, so my knowledge is limited.

      Based on what I've tried already, does anyone have any ideas on how I might proceed? If I can, I'd like to continue to use the existing power supply. At the least, I'm going to have to find a way to get that 115v to the monitor.

      Thanks.
    • Midway games have a lot of issues with the older fuse blocks. I've had to replace them on a number of occasions, but your mileage may vary. Like Mitsu said, follow the AC voltage through the transformer and see if you can nail down where you're losing it.

      Go here for a generic lesson on how the AC wiring in a typical arcade machine works.

      arcadecontrols.com/BBBB/acwiring.html

      It won't be exactly like your Pac, but it should give you at least an idea of what to expect.
    • I haven't read the link you sent, yet, so hopefully the answer will be in there.

      I just measured the voltage going into the filter and it's ~115v. However, coming out of the filter and into the transformers it's hovering around ~5v (it should be ~115v). So nothing in the cabinet is getting power. When I got the cabinet, the ground pin on the plug had been removed, so I replaced the plug last night.

      Are these filters necessary? Can I safely remove it or should i find a replacement?

      Edit: I just read the link you sent me about power supplies and it includes the filter. I guess I'll just build a new power supply. I'm assuming isolation filters are easy to get. I was worried that they would be hard to find.

      The post was edited 1 time, last by cerkit ().

    • Nah, most parts for the AC side are pretty easy. These guys have them, but their shipping can be a bit high compared to the price of the parts.

      twistedquarter.com/index.php?m…o97kjpgo0dthcjq14soo582r1

      You may get lucky and find something at Lowes or Home Depot too.

      The missing ground pin wouldn't cause the voltage loss you're seeing, but it's good practice to fix that anyway.
    • I did some more troubleshooting today and I have to admit that I'm a little embarrassed. I took the power supply and harness out of the cabinet so I could work on it on my bench. I hooked it up to power and there was nothing. I then looked at the schematic and realized that I had to "close" both the safety switch and the power switch. Once I did this, I had the correct voltages on the transformers. So I went out to my cabinet and looked at the safety switch. Sure enough, it was in the "off" position. I didn't know that this cocktail table's safety switch works just like the stand-up cabinet. I pulled the lever out and did a continuity check on it and it was fine.

      I was testing voltages with the safety switch turned off the whole time. So, it wasn't the filter.

      To make things worse, I made a rookie mistake and actually cut wires on my harness to get it out, thinking that I'd reuse the molex connectors for the player 1 and 2 consoles as well as the coin door and monitor cables. I spent two and a half hours soldering the harness wires back together again.



      With the power supply assembly on my bench, I tested the voltages across the fuses. They were terrible. As you can see based on the image, there's a good reason for that. So, I ordered two 4-fuse fuse blocks from Amazon. As soon as they get here, I'll reconnect everything and try again.

      I took the opportunity to clean everything up and wipe down the wires. This cabinet spent many years in smoky bars and there was a layer of grime on the harness. It was so bad that I couldn't tell the colors of some of the wires.

      The post was edited 1 time, last by cerkit: Added harness soldering image ().