I recently bought a Dirty Harry from a friend of a friend. It was his first pin and he just didn’t catch the Pinball bug. It was working at his place when I picked it up. I played a game and could tell it needed some love and a good shop job, but it fully functioned.
Got it home, set up and then 30 seconds into the first game it slam tilts. Played another game for a few seconds and slam tilt happened again. Then upon powering back up it just said “slam tilt switch stuck”.
Long story short, the slam switches were not stuck. I reseated all the connections to the MPU. That didn’t help. Went to bed annoyed, woke up, turned the game on and it played fine again. However, now it randomly and quite often thinks the enter button is being pressed while I’m playing. It beeps like I’m in the menu and says “open coin door to use buttons”. Also, it randomly slam tilts still but not very often.
I installed new connectors on the MPU at J212 and J205 since they looked pretty corroded, but the same problem remains. (See pic). The MPU doesn’t look terrible to me but I’m wondering if these symptoms point toward battery acid damage. I can see a bit of acid damage near the resistors but it doesn’t look that bad to me. The underside of the MPU has no signs of corrosion or cold solder joints.
Thoughts on how to diagnose this problem?