Quoted from PinballManiac40:
But you are seeing good results when you reset that power connector. As mentioned, highly likely the issue. I had seen this on several games I had repaired.
It’s a weird issue. Sometimes it takes a jiggle or a few times of unplugging and re-plugging the 5v connector. Then when put the panel back in the backbox the screen sometimes craps out again. Must be due to something moving the wires. So I redo the same steps.
There is a few kinks in the large ribbon cable and sometimes if I press/squeeze on the kink the dmd starts working. Not sure if by pressing the kink I inadvertently cause movement to the 5v connector at the same time.
So cheapest first is the ribbon cable. Then I’ll try reflowing the 5v again (I don’t have a lot of experience doing this but doesn’t seem to be difficult). Then if that fails I’ll probably get a new board. The issue happens about 1 out of 5 times I turn the game on to play. Not usually at start up but maybe the shaker causes the issue. Once I get the dmd going it doesn’t usually happen again in the same day.