I would check the connectors and consider repinning or replacing them if they are factory. If the main board battery leaked at all the connectors pins below it HAVE to be replaced and maybe even the edge connector pads need attention. I have had to sand them down and then apply a thin coat of solder when the battery eats them up.

PROM should not get hot, warm maybe. I suppose resistance from the socket could heat things up. If you have another PROM, even from a different game, you could try it and see if it still locks up after a while.

Icecreamman: Did you ever get this problem resolved? I'm dealing with a similar problem and would appreciate your imput. I've replaced the PS board and driver board, did the ground mods, checked all fuses, etc. I have not repinned the connectors.

Game boots fine, starts game and then after a couple drop targets, the scoring becomes continuous until powered off. I thought I read on one of the wikis that this problem could be a bad PROM, but it sounds like you've tried several. If there's something that solved the problem for you and will get me out of repinning, I'd love to hear it.

canea, Is this a problem with your joker poker?

Yupe! Sorry, should have specified. I thought the new driver board would solve all my problems and it did solve most them, but now it's doing the continuous scoring.

Did you get your JP up and running?

Pretty much pointless doing all the work you have done unless you re-pin the connectors as well. I have been there and done that and they simply need to be done.

Wouldn't hurt to check the switches on the drop target assembly are all adjusted properly as well if they are continually scoring.

no, not yet, I ordered a new ps from marco and just got it. I am going to install it tommorrow. I will keep you all posted

Solder a heavy gauge wire between the CPU, driver and
supply board ground. Also take a close look at the 5 v power supply.
It could be too high (>5.1v) or too low (<4.8v) and as it heats
up it goes out of spec. Have seen both of these cause the problem
you are having.
Steve

Definitely on the short list. Just noticed that OP had a continuous scoring problem even after repinning so I wasn't sure if there was another root cause that I could check out while I wait for repinning parts. All drop target switches are aligned and functional.

Thanks for the advice and will check these things. I did the ground mods as per pinwiki and the PS is new, but will check also.

Repinned the Joker Poker this weekend (whew, fun). Powered it up, same continuous scoring problem. I went through and cleaned all the switches as they were filthy, and I found that I'd left a couple of stiff, old rubbers on near several of the drop target sets (haven't done anything cosmetic as I wanted to make sure I could get it all working first) that may have been holding switches closed as they'd gotten pretty tight over the years. So, whatever the cause: it's working 100% now. I feel like I've survived some sort of awful trial by fire! Now I actually have to start cleaning the thing and get some new rubbers and plastics.

Good to hear you have got the auto scoring sorted. At least that is one job off the list, I am sure there are plenty of others though....there is always is.

Nice, glad you got it resolved!

i have used the ni-wumph cpu on system 1 and for 120 $ more you can get a pascal jannin 4n1 board that replaces all the boards with just one and eliminates inter board connectors .This is a awesome product you can test and set up game through switch on coin door also the boards tests all coils before starting a game very well designed !

I have both Pascal and Ni-Wumpf boards in my Sys 1 machines. If you can afford the bit extra I would go with the Pascal board - great boards.

This is a common ROM symptom. For those who still have the problem only when it warms up, try staying the ROM with spray cold, or an upside down can of air. If the problem disappears, it's the ROM.