Starting to pull my hair out with this one so I'm hoping someone can help me narrow down where I went wrong. My JD DMD has been taking a while to warm up and the high voltage was low. I'd been putting it off for a while and figured quarantine was finally the time I would rebuild the HV section of the DMD controller board.

I'm now getting 116v, 104v and the 60v reads about 4v and then starts dropping towards 0 with the DMD totally dead. I swapped in the board from my BSD and it boots great, so I know the problem is on the board somewhere.

I'm pretty disappointed that I somehow got a worse result after rebuilding it and figured I must have either shorted something or I'm missing connection on a trace where I should have one. I spent the last 3 hours going back over every component making sure they all tested good and following all the traces I could see to make sure continuity was good and nothing is jumping out at me.

I can get some pictures of the area tomorrow if it would help. This seems like a common issue with these boards but none of the fixes in the threads I found seemed to get me anywhere. I didn't replace any of the caps so that is one of the last things left I can think of but any starting points would be helpful.

Hey Lloyd, thanks for chiming in. The 60v was reading high before I did the rebuild, close to 70 (going from memory, I didn't write it down unfortunately, bah). Before I did the rebuild the DMD would slowly warm up over a few minutes. the 125 and 113 were each about 15v low...110 and 99-ish if I recall correctly, so that's what prompted the initial thought to rebuild.

Now I have 116 and 104v. In some reading I was doing last night I found a few things saying that as long as you have 12v separation there (which I do), the voltages lower than 125 and 113 should be ok - I'm not sure if that's true or not (though I did read it on the internet!).

Now at the connector on the DMD my 60v pin reads about 4v then starts dropping to 0 with the game on, no display activity at anytime.

I'm going to take a look back and triple check everything against the schematic and maybe reflow some of the solder just to make sure i have a connection on the pads, but I was pretty diligent and didn't notice any pads lifting during my work. I'm going to start back at the 60v pin on the board and work my way back through the traces. None of the caps (large or small) were replaced with the kit and I didn't touch the BRs either...so that could be an option but since the DMD worked (although slow to warm up) before, I'm not totally sold on a bad BR.

I just ran across the trace images on PinWiki which I'm hoping will help a lot. Based on what I have read on PinWiki, it does sound like those lower (116/104) voltages are ok and Williams changed them at some point to 112/100v so I'm thinking I am ok there and just need to resolve the 62v problem.

It sounds like I don't need to worry about any of the capacitors on the board...but if those are bad would that matter? What circuit are these in?

Yeah not saying I disagree with Chris, just want to understand why they aren't important. Are they not in the HV circuit? I am going to work through the traces this afternoon.

I spent alot of time going back over the board this afternoon. All the traces in the 60v circuit have continuity on the front and back of the board where they should. I tested BR1 just to rule that out and it tests good also. I am 99% confident that I didn't cut a trace anywhere and held alot of light behind the board as I checked. Not really sure where to go next here aside from pulling and retesting the individual components again to make sure they are good.

I did throw the board in my BSD just to rule out any other board or cabinet related issues and the dmd has no display in that game either.

Sure...let me know if this works. Fuses are good with a meter. Even the areas that look pretty crispy are testing good for continuity where they should, but willing to try whatever!

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No worries, always appreciate a second look!

I'll take a look and buzz them out today. I don't believe I checked that. Do you actually mean ohm or just run continuity to make sure I didn't bridge the solder pads?

Interesting this is great info. I've honestly never tried checking for shorts using ohm measurements before. Are you just looking to confirm there is no resistance between the solder points?