Update - I have re-seated all the socketed chips, re-flowed a stack of dry joints, flicked the red lever a few more times but still no good. There are a few extra sounds working now but the background pulse or hum is still U/S.
The Pinrepair guides talk about replacing a chip, either a 6810 or 6821 chip. Has anyone had any success replacing this chip? Also when I try to run the sound test it doesn't cycle through the various sounds, it just seems to hang on the first sound which doesn't sound right anyway - it is more of a buzz and not the correct background pulse/hum that TW has.
