I stopped servicing almost all solid state Gottlieb games a couple years ago. System 80 is just as bad or worse than System 1, they just added more crap on top of their already bad design choices. I'll work on System 3 if I'm in the mood, but no System 1 or 80. It isn't necessarily that System 1 games are hard to work on, it is just there is so much ground work that has to be done to even get to a solid starting point. Every older platform has its pitfalls and stuff you have to do to make the game reliable, but the early Gottliebs throw more crap at you.
-Can't download manuals (legally) and owners often don't have them.
-Fewer compatible parts meaning I'd have to stock oddball electronic and mechanical parts
-Ground mods take up time and have to be done
-Edge connectors
-Poor diagnostics
-Often unrepairable MPU boards meaning the owner has to spend hundreds of dollars on a game that is only worth hundreds of dollars
-Power supply is frustrating to repair and means more money the owner has to spend if you don't want to bother and put in a replacement. This is bad because power supplies are the MOST repairable board in a game. I almost never replace a power supply, I repair it. Plus someone that is fiddling around can hook up the power supply incorrectly!
Then add in that for every 30-40 repairs I'd do for a Bally or WMS game I'd do one solid state Gottlieb. So the demand isn't there in the first place. So I found it not worth my time and frustration to mess with them and stock the parts. It is unfortunate because I don't necessarily hate the games, I hate the platform.
I could go on, but I've got other stuff I have to do today.