Picked up a Williams Whirlwind and have been bringing it back to life.
I have some random issues to deal with however they seem to be somehow related.
1) The shooter lane (Switch 59) is phantom scoring. First 130, then 130, then 4000. Repeats.
2) The center drop target (Switch 28) is seen by the CPU as hit. When you hit the top and bottom targets the full bank resets and scores even though the center target still stood. Thought it was a bad opto, but a hit on the center triggers the sound effect. So the opto is working.
3)The bottom pop bumper on the upper set (switch 51) will also trigger the left bumper (Switch 52) on the lower set. This is not a result of playfield vibration.
Now what ties these all together is when (Switch 22) the Left lock switch is engaged, all these issues resolve. They stay resolved throughout multiball even after the left lock switch is no longer engaged. But once you finish multi ball and begin the next ball the problems return.
These switches are rather random on the matrix with a few sharing common legs but not all.
Other than these issues the game plays correctly. Switch diagnostics show no stuck switches and register when switches are actuated.
CPU test good
RAM test good
The initial thought was leaky diodes but since this is all over the matrix I am leaning away from that. Thinking this is a logic issue. Bad ROM?
I appreciate any thoughts and input. Thanks