Early '80s Jennings Slot Q

[ramegoom]

I know I know, it's so "yesteryear" but here in IL I'm relegated to 25 year old slots...at least "legally". So I'm currently in the ice ages with my gameroom toys.

So, this tech question is directed to you guys that remember this old stuff. I'm restoring a pair of J700 machines, with the digital readout and loads of LED's for the display lighting. My question is about the coin payout counter. It pretty much sits at 000, maybe 001 or 002, while the hopper is busy paying out way too much after a win. Eventually, the logic kicks out the "Call Attendant" and the machine needs to be reset. But it's not paying properly. So, I'm wondering, is there some sort of feedback between the hopper coin count switch, into the display, then back to the logic telling it that the proper payout has been counted? Seems that way. I don't have a detailed schematic, which would probably explain it all, so I'm trying to muttle through this.

I'm figuring there's a problem with the logic chips on the display PCB, so I'm going through them now. Or maybe it's a wiring continuity issue. Either way, I know the logic board is working properly and I need to find out how it signals the hopper to shut off. Basically it sends out the win count, hopper switch counts down, then logic turns the hopper off. Trouble is, it's not really shutting off.

Thanks for any guidance,
John

[ramegoom]

UPDATE: Turned out it was a bad connection on the hopper connector. Those bakelite connectors are still available, Jones/Molex, but you need to remove one of the terminals and drill out the plastic to re-insert the guide pin. Use the old guide pin on the male connector, and simply drill out the female part with a 5/32" drill bit.

I have four of these Jennings machines, two of them are the 700 series, two are the 400's. Electrically, they're all pretty much the same, with different components added here and there. The 700's use LED's on the display, where the 400's use light bulbs - odd ones at that.

So I'm becoming educated with these things. I would imagine there are some of you out there who used to service these machines in the past, and most of the knowledge seems to be long gone. Too bad. Seems slot machines resurface and tech info can be really useful if it's out there somewhere. The internet can't be a better pipeline for this. So, I guess I'd encourage anyone who has tech knowledge of these to contribute to the cause - before it's too late. (self serving sermon now over).

[uniman]

Thanks for posting your fix. 
Maybe post a pic or two of your machines internals.

You know, it's 2013 so you can own machines 1988 prior. Universals came out in 1985 and I think the IGT S-slot is pre 1988. Believe the S+ came out in 1988. And looks like there's more room in your casino.