I’m pulling my hair out trying to isolate the cause of a JOKERZ intermittent power problem. The machine keeps blowing the F3 & F4 fuses on the auxiliary power drive board. After replacing the fuses, I can play any number of games and then randomly the two fuses pop! The fuses are in the slingshot and pop pumper circuitry.

I’ve checked and re-checked the wiring for shorts, broken insulation, bad solder joints, burned connectors, improper voltages etc. I’m confident my problem is someplace else –at least I’m hoping so! Generally speaking, the machine will blow both fuses after about 20 - 60 minutes of hard play. I’m not sure why the two completely different circuits are popping—there seems not to be any common denominator. Can anyone help with this? Any sage advice for a recommend a path to explore would be more than welcomed. I’ve been fighting this for about two months.

Thanks for taking tine to reply! I’m lost at this point and any help is GREATLY appreciated.

Yes the fuses are correct. I use circuit breakers while I’m working on the pin. And they do pop (2amp & 3amp). But when I do use fuses, they are the correct values.

I’ll pull the board out tonight and re-check the diodes. I’ll re-look for broken joints and bad pads. I’ll let you know as soon as I complete this re-look.

Again, thanks for taking tine to help me step thru this problem— I liked you comment about “change your thought process”. Thanks!

Good Morning Wayout-

ALL the didoes on the AUX Bd check good. Connections are fine. Pins/Pads all are solid too.

Some board history (From Last Week): Q8 on Aux Board shorted last week as I was trying to run down this problem. It gave out during game play, not while I was trouble shooting. I could smell 'heat' from the back box. I immediately began feeling transistors and Q8 was VERY hot. When I checked it--it showed shorted.

Q8 controls special #4--RIGHT SLING. I replaced that transistor -- thought that might have been the culprit-- NOPE. The machine pop both the fuses after about 20 minutes of 'hard' play. Q8 checks good. (I can reset the breakers and machine plays fine.) So I'm back to the 'random' fuse pops which was the symptom prior to Q8 going south.

I'll take your advice and start with pop fuse out, insert an actual fuse for the slings, then begin to investigate the mechanics of the he slings. I'll examine regap & file contacts. I'll pay stick attention to RIGHT sling.

Again, I appreciate you peeking over my shoulder on this one.

Went over the slings. Good gaps. Nothing binding. Free movement etc. Found nothing suspect.

In addition to the SLINGS, Fuse F4 ALSO serves three drop target banks and a ball kicker.

(1) For the drop target banks, its simply a coil that resets the targets. No diodes on the coils, all of that is on the Aux Board. Same for the ball kicker. I inspected each for shorts, bad solder joints, skinned wire etc. All was fine.

(2) Bank coils all measured about the same ohms, and the kicker coil is in line with the others. So I'm ruling out bad coils. Nothing looks dark or burned etc. I'm assuming that if the coils were bad, the game would not play as it does now. Carefully looked for something that could vibrate to a 'short'. Saw nothing.

I moved to Fuse F3. The JOKERZ power wiring diagrams are incorrect -- but usable. Fuse F3 controls three POP Bumpers, AND two ramp flashers.

(1) I've checked the coils on the pop pumpers (no diodes here-- done at Aux Board) and the flashers are fine. None of the pops or flashers have bad wiring, bad soldering, loose connections etc.

(2) The flashers are simply flash lamps no mechanical parts. They work, I'm not sure how to check that circuit for problems.

I played the came for about 1 hour (with fuses not breakers) and it played fine. But I've been down this road before -- playing with fuses, then randomly popping both!

Summary for today: I've not found anything or solved any issues yet. So I'm sure they will blow again soon.

Standing by for your thoughts Wayout.

Bob

Morning Wayout.

Hope you had a good holiday-- we had a house full -- and it rained here all day. But the BBQ ribs were good. So today, I'm back to pulling what few hairs I have left tinkering with this JOKERZ.

Yes, the A/C relay is a mystery to me too. But the transistor was cooking/cooked.

(1) D23 is fine. I did in fact remove one leg and checked it.
(2) I've checked each diode on the board. All were fine -- checked both forward and backward.
(3) For diodes on the AUX Board that are not in a circuit with other components (only connector to connector) i did not remove a leg. Just checked from connector to connector.
(4) The relay coil is not shorted (ohmed it); further, in the "COILS" test mode, it cycles (clicks) just fine. BTW, the relay HAS been replaced at some point.
(5) I inspected the board connector pins (under magnification!) did not see anything suspect. Flowed a bit of solder on a few, but I think they were fine.

Assuming that the problem(s) are NOT on the AUX Board. Where do I move next? What else could be suspect? I'm totally lost on why fuses would pop like this. No component on the AUX Board seems to be of consequence. The B+ is there for the coils/flashers. I'm assuming the affected coil driver transistors are OK as they are working (notwithstanding randomly fails).

So, is there any merit to think that there maybe something on the CPU Board driver path is failing? I would not know how to begin looking for a 'randomly failing part'.

I do appreciate your insights. And taking time to give me some ideas. I'm standing by for your next instruction.

Bob

It’s a game of a friend. He got it online several years ago. It worked fine then started this problem. Before I knew him, someone else tried to “fix it.” The guy could never solve the problem.

Once we became friends, he asked me to take a look. I replaced a bunch of broken stuff, including display. I’m now down to this.

I’ve resisted purchasing a new Aux Power Bd, as I’m not convinced that would fix it as I cant seem to find any issues with this one. No burned or darken pins, so I don’t think excessive current draw to bad connectors is an issue.

I’m in a small town— and NOBODY here deals with pins— so I’m kinda all alone on this.

My PS

pwrSp (resized).JPG

Here is Aux Board.. note jumper w6 how its discolored. Note darkened W4 from white to brown.

auxW4b (resized).jpg

Here is product

F387EB17-73FF-4C54-8DF2-D1F0DF2DEE51 (resized).jpeg