The Shadow's giving me some trouble... Power on and everything works as expected. Part way through the first game (at different times during play) the DMD will go blank, then displays a few glitchy images and eventually stays blank. At this point power cycling doesn't reset the display, the game needs to be off for an hour or so, then comes up fine, but goes blank again as described above. Also doesn't require gameplay, if left on, within 30 minutes of attract mode the DMD will go blank. Prior to blanking the Display Test works fine and the RAM passes. All voltages at the power connector are normal before and after going blank. I have also reseated all ribbon cables with no change. Any thoughts? Thanks in advance.

Will check and reflow if necessary. That said, manipulating that connector didn't have any impact on the display.

No dice. Hard to see the solder side of the DMD HV connector as it's under the display panel itself. However I did confirm continuity at each pin and wiggle them without any sounds of an open circuit, imperfect I know. I also reflowed the pins on the driver board side. Same result works perfectly for a few mins, then gets scrambled and goes out.

Yep, that helps narrow it down. Swapping the DMD control board solves the problem, so presumably that's where the problem lies. I took some readings from the power supply connector after the DMD had blanked (using problematic Shadow board), and then some from BSD (with it's working board) for comparison. Sorry about the formatting below, but you should be able to decipher the scrunched up numbers.

Pin Shadow BSD
1 -121 -118
2 -121 -107
6 4.97 4.90
7 12.50 12.28
8 66.2 63.0

The only only value that looks a bit out of range is pin 2, which seems a bit more negative than nominal. Not sure if this would cause this problem or not. I'm going to let the machine "cool down", although this might very well be temperature related, and take those readings at startup when then DMD is working. In the meantime if this means anything to anyone please let me know. Thanks.

According to the PinWiki it looks like the difference between pins 1 and 2 is critical. I'll still do the follow up testing, but it looks like I might need to rebuild the HV section of that board. I recently did this for a STTNG and it wasn't too bad. I also think I picked up an extra repair kit from GPE when I needed one of the STTNG.

Yep, R43 (actually on mine R8 for WPC) was reading >1M ohm. I pulled the 4.7K 5W resister out of the GPE kit and tacked in temporarily. So far the machine has been running for a hour and the DMD is still fine, so it appears that in fact was the issue. General question... When the DMD power board failed in my STTNG it was blowing one of the fuses on that board, I can't remember which. I also tested a couple of components and found them to be either bad or further from spec than I preferred. So, I rebuilt the whole HV section. In my current situation would you simply leave it at replacing R43/R8? It doesn't look like form the schematic that if that resistor were to fail open that other parts would be damaged. Obviously the board is a bit toasty in that area and I'm sure some of the components could be replaced, but as of now everything is working fine. So, do anything more or just permanently replace the failed resistor? Thanks again for everyone's help.

Thanks Chris, that's my inclination as well, but honestly the reason I asked is I was expecting to get an "if it ain't broke, don't fix it" response. I'll swap out the rest and forget about it. Much appreciated.