The fact that it was working when you bought it and not when you got it home screams "bad connections". And as you have already mentioned, system 80 games are known for having poorly constructed harness/pins/connectors. One of the easiest/quickest/cheapest steps you can take to make these connections better is to clean the finger board contacts (edge of pcb where connector attaches) with a fiber glass eraser. This is constantly an issue as they become tarnished, resistance builds up and signals are lost or floating. Don't use sand paper, don't use an eraser, get a fiber glass eraser and clean them properly.

From there you want to remove and physically look at each connectors pins and determine if they are tarnished, bent down, broken or loose. Pins that are not inline with the majority of others are probably worn/bent down and need to be removed, either using a pin remover tool or bobby pin, paper clip, exc. and then cleaned/bent back to their original position so they can make firm contact with the board edge contacts. If they don't feel springy or look rough they may need to be replaced. Specifically the power and ground pins are your main culprits. Most of the other logic signals are low voltage lines that probably have little to no damage on the pins. Confirm continuity with your meter on every pin or connection that is suspect.

Do these steps first before repinning every connector. Pack a lunch if thats your plan as it will take a while.

For your sound board, its good that its outputting in test as that means the amp is good. I don't have time to look at a schematic right now but I'm curious if the input signals during a game are not getting through to the board. Maybe a bad buffer on the CPU?

For your drop targets, do they ever reset? During the start of a game? Or are they down 100% of the time? If down all the time check your reset coil for both power, ohm, and leads. Make sure the leads from the windings or the wire harness leads are not broke off the lugs. If all good then confirm/test associated driver board power and pre driver transistor.

Fiberglass erasers are used on IC pins everyday. They are NOT like sandpaper. And do a better job then any eraser in 1/10 the time.

I’ll add that whenever your cleaning any contacts (legs on ICs, edge contacts (finger board), pins in a harness, pins on a board) spray deoxit on the cleaned area afterwards. Specifically with ICs if you insert the IC into the socket it cleans the female pins of the sockets.

This is the best way to clean pins and contacts and decreases resistance as well. Always wait to power up until dry. Blow it out with some canned air if in doubt.

Disagree.

There is an industry of technicians/repairman using fiberglass erasers and have been for decades. The goal is to remove oxidation not the plating. Fiberglass erasers work great for that. If someone continues to use it on one contact well after removing the oxidation then they might need to understand better what it is they are trying to accomplish. If that’s what your referring to when you say “grime” then again I disagree and highly recommend swapping out the #2 pencil for the proper tool to do the job.

Deoxit is great for its cleaning ability. Not magic. But helpful in tight spots like sockets. Spray on the IC legs after cleaning and insert into socket. Remove and let dry/blow out then resocket. If connections are still poor swap in new sockets as they are more then dirty. Wiping down finger contacts after cleaning mechanically provides further cleaning.

ForceFlow

Missed your T2 this year at the Saratoga pinball show.

You make it to pintastic this year?

I must have missed it. Loved playing it in past years. Nicest T2 I’ve seen/played.

We went Saturday. Although nowhere near as many pins in the free play room as years past, still plenty to do and enjoy.

Merry Christmas