Joe,

This sounds more like a monitor adjustment issue than a board issue. While a board issue is a definite possibility, the fact that you get some picture and sound makes me think it’s OK. We would start off by hooking up the Tetris board and adjusting the monitor settings to see if we could get the picture dialed in. Different boards put out different sync frequencies and it could be that you need to adjust your horizontal and vertical frequency/hold/sync potentiometers (or pots) on your arcade monitor to get it to display properly.

Also, I noticed on the pinouts for Tetris that it requires the -5 VDC line to be hooked up. Most Neo Geo boards don’t require the -5 VDC to be hooked up so it could cause some problems if the Tetris board is not getting that negative voltage. Same goes for the ground pins at the bottom of the harness as well (pins 27 & 28). While some JAMMA games don’t require them to be hooked up, others will do some funky stuff if they are not getting ground on those pins. It might be worth rewiring your cabinet to add these wires (if they are not hooked up already) if you plan on using different JAMMA boards in the cabinet in the future.

Hope that helps. Thank you for your question and good luck with your repair.