I recently did a lot of "refreshing" on my STTNG including replacing the lower half of MPU due to alkaline corrosion, replacing all electrolytic capacitors on the sound board, dot matrix display board, and power/driver board. I also replaced BR1, BR2 and BR5 on the power/driver board. The game worked/works 100% before and after but I noticed (or maybe I'm losing it) after all the work was done the typical hum from the DMD got louder and on top of that when many of the dots are filled there is a very, very faint "strobing" effect across the whole DMD and the humming goes as if something is working hard. I measured the voltages as
Plugged:
1-117v
2-104v
7-12.25v
8-64.2v
Unplugged
1-117v
2-97v
7-12.3
8-64.4

I checked on pinwiki and everything seems fine including the 20v pin 2 variance from pin 1 when unplugged.

Edit: Forgot to mention that on the dot matrix board I put the two old filtering caps in as I got a couple 160v 220uf caps and thought that might have been the issue but the issue remains even with the old filter caps.