So I've been working on this one off and on for a while now (way more "off" than "on).
Here's my original thread: http://pinside.com/pinball/forum/topic/mr-mrs-pacman-lamp-and-display-issues

Quick recap:
I have an Alltek mpu. I have reflowed all the boards, rebuilt the driver board, replaced all main chips on both lamp boards, and replaced all of the .100 connectors in the backbox.

I went from no lamp life to having them work perfectly finally... For a few minutes. After 3-5 minutes, strange things happen with the controlled lamps. Some lock on, some stay off. Now that most work though, I saw a new symptom- in some places the wrong lamps are being turned on. This is most noticeable in the maze. The reds proceed correctly, but the yellows break away and do their own thing.
This morning I tried again with the machine cold and it worked again correctly for -3-5 minutes again. Consistently the lamps work correctly when the machine is cold started, and they go wacky after the same 3 minute period.

What in Sam Hill Tarnation is going on here?!?
I took a video, and will load it up to youtube eventually.

Just put two and two together:
I abandoned my sound issues a while back to focus on the lamps, so I've had the sound board unplugged for a while. It dawned on me though that the wrong sounds were being triggered too. They also worked correctly for about the same time period on a cold machine, then just started going nuts or flat out going silent.
I didn't realize the wrong lamps were being triggered until this weekend since so few of them worked until now.

Sending MPU off to Alltek to be checked out.