Hi guys, I'm trying to help someone with their Panthera. I have very limited experience with Gottliebs, and the System 80 stuff is almost nothing like the Bally/Williams games that I'm used to.

Right now the first of two issues is that when coining up, the game displays go blank and the game locks up. Nothing will respond. If I restart the game, then the credit that I applied will show on the status display, and I can start a game normally. The right chute will do this with any # of coin-ups; however, the left chute will be fine for the first credit, but if I try to coin another credit I get the blank display/lock-up behavior. I'm kinda stumped at what's causing this.

Prior to this weird behavior, I applied the jumper mod to the diode strip in order to enable free-play for the owner. It worked as expected initially; one press of the start button would apply a credit and then use that credit to start a game. It was fine for a couple hours while I continued to work on other issues with the game, and then all of the sudden the game started doing this weird coin-up stuff. I de-soldered the jumper just in case it was somehow causing the weird behavior, but there was no change; the weird behavior continued even without the jumper.

The second issue is that the game credits and high scores aren't saving when the game is powered off for more than a few seconds. I noticed that there's no battery on the MPU, and no apparent alternative installed. Looking at the picture below, is it safe to say that I need some sort of battery there? I was thinking of installing one of those capacitor 1F 5.5V "SuperCap" watch-battery looking things.

I read that without batteries installed, Sys1 and Sys80 games can exhibit weird behavior. Do you guys think that the lack of a battery could also be causing the coin-up issue? I'm kinda stumped here with this one.
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Oh, so could it have NVRAM installed on the other side of the board? Didn't know that. I suppose that I could pull the board and check next time I'm at his house, but since it's not saving credits, I'm guessing there's nothing there. The owner of the Panthera bought it from a seller in Virginia and had it shipped to him here in South Dakota a few weeks ago. So he doesn't know a whole lot about it, and couldn't play it before he bought it. Plus, who knows how much it got shook up in transit, or what it was like when it went on the truck. The credit display had about 10 broken pins and was half hanging-off the display board when I opened the backbox, so I wonder how much vibration or damage it sustained. I fixed the display btw, had to resolder the broken pins, and then all was good with it.

Not sure about the ground mods. It doesn't look it to me, but I really barely know what I'm looking at with these Gottliebs. How would I tell, could they be run along the back of the boards? Here's a larger picture of the board. I also checked for the extra ground wire that ToddT recommends be put on the last A1-J4 connector, and it looks like there's only one wire and not two. So that's not been done either.

I also asked my stepdad who's worked on a few Gottlieb System 1s in the past, and he'd never heard of a game freaking out after being coined-up multiple times. Any idea what that's about?

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Appreciate the help gman. Would be nice if installing a battery fixed the coin-up issue. It's just such a strange thing.

Well, I installed a supercap for the battery and put in the extra ground wire for the MPU to Driver board connector. But sadly, the game is acting just as wacky as ever. It still won't save high scores or credits. So either there's a problem with one of the memory chips, or with the traces. There seem to be a lot of past repairs to the MPU. At this point, I recommended to the owner to just go ahead and order a replacement MPU from Rottendog or Ni-Wumpf. I just don't think it's worth his or my time to keep trying to make this old MPU work. And since I don't know these old Gottliebs very well, being able to eliminate a major source of problems would be helpful.

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I did manage to find a few different options in stock on several websites. A local guy who is an EM and Early SS expert has taken this project on, so it's out of my hands for now. I'm guessing a new MPU will solve most of the issues.