I have a Firepower and the right ball lock (switch 30) is being finicky. I cleaned and adjusted the switch and replaced the diode. I also checked for broken wires in the row and column of this switch. The switches test fine if jumpered on the driver board header pins during switch test. They also register fine if switches manually triggered during switch test (connectors plugged back in). I think there could be an issue in column 4 (column the right lock is in) since sometimes the "F" switch and top middle target switch don't register in game play. These are in the same column as the right eject. BUT, these switches register every time in switch test. What is so different about game play that is causing this flaky issue? Diodes? All wiring appears to be in tact and nothing shorted that I can see. Nothing more frustrating than finally locking a ball only to have the game decide to look the other way.

The locks ejects the ball every time there is a ball if machine is turned off and back on. For example, if during a game I get a ball into the lock/saucer and the game doesn't "see it", I turn the game off and back and on and the game instantly ejects the ball 100% of the time.

Tell me more about this comment, "Intermittent switch shorted pin on driverboard"

I'll try this, thank you!

I did the reset as described above. I started a game and manually rolled ball into saucer and it sensed the ball and ejected it multiple times. I played a few games and finally the lock did not sense the ball. I turned the game off and on and the ball was instantly released from the lock. Every time the lock switch did not sense the ball, the "F" roll over switch also stopped registering a switch close. This sequence happened multiple times across a few games ("F" switch not working and right lock not sensing the ball). RAM issue?

Leaving the glass off during game play and triggering other switches in column 4 (right lock switch in this column) indicated that all switches in column 4 go out intermittently during gameplay - but when 1 switch goes out, the whole column is out. The 7406 for this column at IC17 was already socketed, so I swapped in a new 7406 chip, but no change to the switches intermittently not registering for the whole column.

I'm thinking maybe connector 2J2 on the driver board (Switch column drive) could have a bad solder joint at pin 6 or need the connector housing re-pinned and replaced. Anywhere else on the board I should be looking?

Thanks!

To confirm, based on the assembly drawing, this would be the PIA at IC 11, correct?