Here's a follow up image from my first post on this Bally 1978 Playboy machine. I've opened the backbox and the mpu looks like this (mainly corrosion on bottom). The light blinks
Bally Williams Pinball Machine OEM Triple 3 AA Battery Holder 5881-09021-00 New! | eBay
Standard Williams/Bally WPC Battery Holder
Complete Left flipper assembly used on System 11 games and early WPC games Williams/Bally #C-13174-L (left side)