Bally Midway Power supply workaround (down & DIRTY)

This is a description of how I more or less got around a damaged power supply in a Burger Time Cabinet. It's not amazingly insightful but rather my solution based on my knowledge and ability level. I am sure this will make some collectors and purists cringe but it works for now and Doesn't seem to have any advers effects on the machine...

The problem with the game (aside from the fact it didn't work) was that when I plugged the PS harness into the board and fired up the cabinet the 5V circuit would drop to less than 1 volt and the fuse would blow out after about 30 seconds. After spending 4 hours changing the electrolytics and trying to find a shorted component on the game board I decided on a lark to hook it up to a known good PS. Low and behold.... no shorts, must be the PS.

I pulled and checked the CAPs and diodes on the old supply and didn't find anything I thought was bad. Looking at the other components I decided that at this point I was more likely to do more damage than good and I really have no way (or knowledge of how) to test the big transistors and voltage comparators under load. Additionally since there is no "parts" store local that would carry these dino's I hit on a simpler idea.

Since I had several older switching PS laying around why not graft one into the older PS ? As it turns out all the 5V out pins on the original PS are grouped together (except for one that is not passed to the game board) and they are fed from one large trace on the PCB that has a clear straight run with an area that is void of other traces on opposite side of the board. If your a purist you should stop reading here.....

At this point I went past the point of no return and cut a 1/4" gap into the trace between the out feeding pins and the last component. I ohm'd out the board in order to assure there was no connection between the pins and components. I disassembled the good power supply to the point that there was only the board itself and 2 wires (5V and GND) and the AC pigtail coming off of it. in order to ensure a good and lasting graft on the old board I scraped the solder mask from the pin side of the cut trace and a portion of the ground trace that encircles the old PCB and drilled a small hole in each (making sure there was not a trace on the opposite side.) I soldered the leads from the new PS into the new "pads", plugged it in and fired it up (sans game board.) Everything checked out fine voltage wise and there seemed to be no over heating issues anywhere (finger test.)

The next step was to bite my lip and plug the game board in. When I did everything checked out OK voltage wise so I let my breath out, unplugged the power and disconnected the boards. When I assembled everything back in the cabinet and turned it on I was very happy to find Peter Pepper running around his little world of ladders and platforms. A week later the machine is running flawlessly.

There is no great electronics tutorial here (I'm a carpenter not an EE or tech) just a description of a hack I made in order to get my fifty dollar BT cabinet up and running. Hopefully it may help someone else under similar circumstances....