I didn't read all 10 pages but has anyone had success with a new rottendog power supply improving the hum? In my case I don't want to install a switching power supply, I consider that a hack, but to each his own. The dmd makes it's own mild hum but doesn't improve the sound hum when unlpugged. If the lamps are contributing to the hum, I plan on switching to LED's anyway, wondering if that improves the hum. I may send my sound board out for a recapping just for the hell of it if nothing else works, will report back.

Thanks for the input. I'm hoping the newest revised rottendog power supply will help more than hurt, needed one anyway. Then I'll swap out LED's, then I'll probably recap the sound board whether it needs it or not but I'm sure it won't hurt. BTW, not in this particular case, but I have had some improvements in the past by tightening the 4 bolts that bolt down the transformer, worth a try.

I was talking about the bolts that bolt it down to the bottom of the cabinet, not the bolts that go through the actual transformer. The idea being it helps to ground the transformer better to the ground strapping that runs underneath it, and I always seem to find those bolts are loose. It's not a miracle cure by any means but has improved the hum in a few instances.

Okayy, well a little feedback on my experience to get rid of the hum. Installed a new rottendog power supply, new speakers, new ribbon cables, checked all the grounds, groundstraps etc, tightened transformer, had ALL caps changed on sound board, isolated ground on sound board with plastic washers, MUCH improved but still a mild hum. Installed an auxiliary power supply and no hum! So like many things in life I took the long way around the block, I don't usually give up easy and I inherently do not like to hack machines (at least I consider it a hack-however neatly installed and reversible). And so now I know what I need to do in the future with Data East hum problems......

I used this: ebay.com link: MEAN WELL RT 50B

Been about a year, got rid of the hum, holding up fine. Small enough to hide in the backbox, no complaints.

I found a place in the backbox to mount the power supply. I disconnected the power plug to the sound board and tucked it away and made up a new harness with connectors to go from the power supply to the power in to the sound board. I like to do things like this reversible so things can be put back the way they were and not permanently cut alter or hack the existing wiring harness. It's best if you try to use color correct wires when making up the harness, black for ground, red for +5 etc. Then I took 2 longer wires for the 110 ( black & white ) and ran them down through into the bottom cabinet and tapped off the 110 from the transformer. I checked to make sure it was switched so it goes on and off with the power switch. All wires neatly zip tied or tucked into the cable clamps so it looks factory.

Would this work on a sega terminator 3 ?

Thanks for the info, I read up on that while googling, think I’ll give the resistor fix a try.

I've worked on and sold enough new Data East games to confidently say, they did not hum like this when they were new.

I think many of you are forgetting the original fix for this. To buy a small power supply, I used the mean well rt50b (about $40) . You mount it wherever you want, tie it into a switchable 110 so it turns off. Then run wires to the connector that supplies power to the sound board and disconnect the old one and tuck it away. I think it's ground, +5, 12, and maybe -12 0r -5, I forget, but it's somewhere in this thread. It's not that difficult. I've used this method many times and it always worked.