J400 Jennings Logic PCB

[ramegoom]

Quick tech question: What does the trimpot on the J400 logic board adjust? Is it the system clock?
Thanks!
John

[slotsteve]

we use to sell jenning in mid 80,s  i thinking  time of reel spining , but i drank alot more then and a lot is still in a haze

[ramegoom]

I'm thinking you're right. So, I'm gonna tweak it and see what happens. Old-school TTL logic, must be a clock for the system.

Any chance a schematic might be available out there? Anyone?

[slotsteve]

in the 80,s we bought a lot of them thur a bank in reno  who held the paper on them most had dead batterys was a great deal at 100 each, shipped them back east by air for 25each to philly , those were the days

[ramegoom]

The battery on the board is a 4.8v NiCad, and it has corroded and leached all the acid onto the board. No longer available, but I am using a cordless phone battery pack in its place, wired in. The original battery holder is all rotted out anyway. Otherwise, the machine works perfectly, managed to get everything right.

The ratchet on the handle was missing, so I had to fabricate one based on an old picture of the handle mechanism. This is getting to be fun....newbie sucked in to this world!

[slotsteve]

enjoy your new toy they are fun and more fun when you fix something on them yourself

[ramegoom]

OK, experimenting with the adjustment, the trimpot sets system clock speed; the time in milliseconds that the reels spin, before reel 1 stops. I can speed it up, reels won't even spin one revolution, or slow it down where they spin about three revolutions before the first one stops.

The only problem is, if you run the reels longer, the "set" time for coin acceptance also lengthens. This is a problem when you feed coins as you have to wait for an unusually long period of time before the coin mechanism can accept coins.

So.

I need to know where in the circuitry the coin acceptance delay is controlled. It must be a delay based on clock counts, i.e. x amount of clock cycles before "coin accept ready" can occur. What I'd like to do is shorten that time sequence, possibly bypassing a portion of the clock counter register to cause the coin accept ready event to occur much sooner than it's designed to do.

I am probably far reaching with my thoughts, but I'm putting it out there anyway, hoping someone in the tech arena actually understands what I'm trying to do. It's pretty simple TTL logic, and I am certain it can be done. I just need a schematic to start with.

Anyone have any ideas?

Thanks for any insight.

[Op-Bell]

Email sent.

[ramegoom]

@op-bell THANKS for the information. I am decoding the pinouts and will find a way to accomplish what I'm after. I read other threads about how addictive these machines become, and here I am at the beginning of it. Oboy here it comes...

I am into cars and this slot crowd is no different. Once you get started!

Thanks again. I will post results. Also, I am taking out the factory battery holder and replacing the battery with a cordless phone battery pack, will post pictures on that as well.

[ramegoom]

Battery replacement. This was simple, but I'm posting hoping possibly it will help others with a similar problem. The original NiCad was long gone, rusting and destroying the original clips and part of the PC board. Cheap cordless phone NiCad battery, soldered in, problem solved for the next few years anyway.