Thought I get some help from the community. I'm attempting to repair the controller board for the Sega Baywatch pinball machine. It suddenly stopped working. All it does that it shows a blank orange video. It constantly resets. Found the video controller chip damaged by corroded pins. No other corrosion found. As I attempted to replace it (including socketing) and with a new replacement chip, the display went completely blank. The resetting happens about every ten seconds. I can see that it will temporarily blink a bright line as it cycles. That's all it's doing. There's 4.95 volts measured at the controller board and the game has a power cable mod to send the proper voltage to the controller. Measured 18 volts at the DMD's 4-pin connector. Baywatch Mary Shelley's Frankenstein Maverick Batman Forever

I'll be testing them on my workbench and switching power supply tonight to see if there is a difference. If not, I'll re-examine the repair and go from there.

Got them on the workbench with the switching power supply at 5.2VDC and 12VDC to the DMD.
after an exhaustive effort to determine if all signals are being accessed via the video chip (U8), I discovered that the CS signal was severed by its chip. I could not see the trace because it was tucked under the heavy-duty socket I installed. (I'm not going to buy those ever again). Bypassed the trace with a wire, tested continuity and it is reconnected. I turned it on and with the oscilloscope I found signals present on the DMD connector! Powered down, hooked up the DMD display. Turned it on, I got back a blank orange display. I'm scratching my head. Then, I tried wiggling the 4-pin connector on the DMD. Now, I have random bright dots scattered across the display. I wiggled the 4-pin power connector again after I briefly inspected the solder on the other side. I wiggled the 2 pins to make a better contact. I got this:

20170819_000717 (resized).jpg

As you can see, I am measuring the voltage off the controller board with one lead in the jumper and another connected to the edge of the board (off pic) via jumper. Now, I decided to run a stress test. Check this out and watch the volt meter as I adjusted the amount of 5V power off the switching power supply:

20170819_000633 (resized).jpg

20170819_000652 (resized).jpg

Ugh, the photos were reversed. Oh well.
The entire controller board successfully booted up on all 3 different voltages. I need to have a solid ground on the ground pin on the DMD when I'm going to put it back together.

addendum: issues why it won't boot would either be the CPU or the memory chips not working. To my knowledge, there's no known way to find out of these two other using the traditional methods to check. It be nice to have a diagnostic LED and bootup code to determine what went wrong.