Indy Heat: help with a few issues please (video of issues included)

[Lukenatme]

I just got this and haven't been able to get sound.  There isn't the slightest hum or other sound when adjusting the volume knob.  Also, the display is glitchy, but for a split second on certain screens is almost normal.  I used a multimeter to get these readings:

+5 is a steady 5.10
-5 is at 4.9 (not sure how to adjust -5)
12v is at 12.8

All sound connections appear as good as the others, but I don't see how to access the speakers. I removed all layers of the plexiglass marquee nonsense and the light fixture but am not seeing any way to get behind there to check the speakers.

Also, the picture is a bit off color and the amount of artifacts varies from screen to screen, but when flexing the braids, I have caught a glimpse of perfect screen colors so I assume one of the several braids aren't just so. No idea which one since it appears to be one of the several screwed to the box housing the interlocking switch and main power fuse. When I got this, one of the ground braids was floating unattached so I added it to that cluster since all other metal it could reach seemed to make the picture worse. Here is a video: