(EDIT: Just did some quick reading and found that it could simply be the connectors are wearing out. One thing I did notice when I bought this thing is that while the boards look pristine, the connectors look mostly original. I'm gonna try reseating some connectors in a bit and see where that gets me, but I'd appreciate any other advice anyone might have.)
OK, this is annoying. I just picked up a Hollywood Heat a week ago as my very first pin, and one of the things I made note of while looking at the inside of it when I went to buy it is that the boards and everything are in really good shape. Some of them even look like they've been replaced at some point. The battery pack was also replaced with an off-board rechargeable phone battery of some sort back in 2011. (This may be an important point of note, but I'm not sure.)
I've also barely put any play time on the thing. Maybe a little over an hour as I only finally got it up and running back on Wednesday after repairing the AC plug, removing a shattered bulb, and doing checks under the playfield and such to confirm everything was OK. Last time I played it was working perfectly fine.
As another point of note, the very first time I tried turning the machine on after getting it, the display didn't come on, yet after turning it off and on again, it came on fine and came on fine since... up until today.
Today, I turn the power on and the display comes up with constantly changing random garbage characters, yet everything else seems to be working as it goes into attract mode perfectly fine. I try turning the game off, wait a moment, and turn it back on, and now the display isn't coming on at all, yet everything else seems to be working. Attract mode is going, credits can be registered, slam tilt is working... I haven't tried starting a game yet, admittedly I should've but I really need to get back to work on other things.
So... what should I check first, what should I check second, what should I check third... basically, if the display showed random garbage at one point and now is not working, but everything else is working fine, what are the possibilities?
Post edited by Gemini: Added a note on the first thing I'm going to try when I get a chance.