What could be causing those few lines appearing on the DMD of my Lethal Weapon 3? What can I check out?

Thanks. I did reseat all the cables and this problem persisted after I upgraded the ROMs to latest version. I'll take a look at replacing the cables, or seeing if I have the same cables in SST or TFTC, and test using a known working set. Thanks for the idea.

I just swapped the ribbon cable with TFTC and still have the lines. Then I decided to swap the DMDs and the LW3 DMD still had the lines when installed in TFTC. So that would at least isolate the issue to the DMD. The issue was there when I got the game and upgrading the display ROMs did not eliminate the lines.

The braided ground wire was getting frayed so I made new ground wires that connected the DMD and speakers to the backbox. Didn't help, but needed to be done at least.

Selling the game anyway. The DMD never bothered me, but since I was getting ready to sell it, figured I'd see if it was a relatively easy fix.

Could low 12v from on the power supply board be causing the issue? Getting 10.7v using the test points on the board. Getting -14 on the -12v test point. 5v is fine.

Measurements on the P1 connector on the DMD are in parenthesis. You can see pin 1 and 2 are quite a bit low.

P1 pin 1: -110 volts (100v)
P1 pin 2: -98 volts (90v)
P1 pin 3: KEY
P1 pin 4: Ground
P1 pin 5: Ground
P1 pin 6: +5 volts (4.99v)
P1 pin 7: +12 volts (11.9v)
P1 pin 8: +68 volts (70v)

Ok thanks a bunch for that info. Just wanted to be sure I checked everything I was capable of before putting it up for sale.