Some IC sockets used on bally boards have contacts with leafs that like stick to the pad on the top side of the PCB when vac desoldering. A trick I would use is desolder out the hole clean and while the leaf is still hot, use the tip of the desoldering gun to gently push the lead back up towards the top side of the board. They usually fall right out or will not be stuck to the top side.

The black closed frame sockets with paper underneath, pull the socket frame off and then they desolder pretty easy

The orange closed frame ones desolder pretty easy with a FR300 in good working order.

If the frame can come off, it do it. Usually makes desoldering easier. Sometimes you cant tho.

Interesting effect that resistor had. The 56k resistor is a pull downs on the switch returns.

Usually resistors are visibly burned open or that have some kind of mechanical failure. Like a broken lead right where it enters the resistor body can be tough to visually spot.

The games probably use different parts of the memory for different things My test bed is a Black Pyramid a lot of times. When i throw different game ROMs in after being played as BP, usually a lot of the audits have ramdom crud in them. BP must use certain areas of memory for gameplay stuff while other games use that spot of memory for an audit.

Will they return.... Maybe? The fm16w08 will hold the memory unless the other game wrote over top of it.

I just shipped out a MPU for Stern Magic. It got tested and then play tested in Black Pyramid. The FM16W08 come blanked out so all the audits are 00 on first boot. Play test good, install Stern Magic and more than a handful of audits have crap in them. One is always 300,000 and some others like 33,000.