I have two different Q*bert boards, both of which have issues. I was hoping to combine components from both into one good board, but I'm not sure which should be the donor and which the board to restore. I've reflowed the filter board, rebuilt the PS board with the exception of the D26 diode, which I've ordered a replacement for (the current diode reads 33v, I've ordered a 27v replacement), and I've removed the faulty LM379S just in case it was causing a voltage drop while I wait for the replacement to arrive.
As far as the individual issues, rather than explain it, I'll show you.
This is my first board...
...which glitches in random ways. Sometimes the foreground shows up fine and the background glitches, other times the background is fine and the foreground glitched, and sometimes both glitch. The only thing consistent is the manner in which certain things glitch, like the 888888s across the top of the test screen, the weird box instead of the arrow on the aforementioned screen, etc. Test mode flip flops around (I've replaced the old toggle and pushbutton switches on the cab to no avail).
And the second board:
This board does some really weird stuff. Test mode comes up without any flip flopping. Object Priority screen onloy shows blue boxes in place of the discs, and the bottom row appears at the top of the screen, partially offscreen. Out of test mode, the screen has a reddish tint to it, and the screen flips around, first upside down, then upside down flipped, then right side up, and finally right side up flipped. Foreground characters either do not appear or appear as blocks.
The first board's had a cap kit installed, has no battery acid damage and has had all the IC and board contacts cleaned and polished, including the harness connector. Second board hasn't had a cap kit yet (I just received it from a fellow KLOVer yesterday) and hasn't had the contacts cleaned yet, but there isn't any acid damage here either thankfully.
Hope that's enough to start off with. Let me know if you need any more info.