Bally Black Jack switch matrix issue

[Menace]

Yeah, not surprising. From where I sit this seems like an issue under the PF. Something is touching something it shouldn't be.

D

 

[Mxzmark]

Ok getting closer. If I disconnect all the connectors from the lamp driver board the issues goes away. If I connect just A4 to the lamp driver the issues comes back. A4 connector only goes to the transformer and the mpu.

 

[cdnpinballer]

Check the schematics wiring diagrams to make sure each wire on that connector is in the correct spot.

After that I would go around and make sure there are no lamp sockets touching any wires or switches they are not supposed to be touching.

As a last resort I would start taking apart the wiring harness to that connector to determine if there is anything else wrong inside the harness like broken wire casings causing a short within the harness etc...

 

[Mxzmark]

I was wrong it's still doing it with the lamp driver disconnected. I have checked again and there are no lamp sockets or wires touching any switch. Is it possible that I have a bad chip on the mpu that is causing this? I have already swapped u10 decoder. I'm going to double check all the harnesses against the wiring diagram but I'm sure they are fine as the game was working fine before I cleaned it up and I never removed any wires from the harnesses. It's not happening on just one strobe or return is happening on all strobes and returns.

 

[cdnpinballer]

Do you (or someone you know) have another MPU like an alltek where you could drop it in to double check that it's not something on that PCB?

 

[Mxzmark]

No I don't have one or know anyone that has one. I have a mpu from my "stern stars" but I will have to change over the roms to try it.

 

[cdnpinballer]

You're not far from London. Maybe there is a London based pinhead who could help you drop in an Alltek?

 

[Menace]

Contact Corey @ londonpinball.ca

D

 

[Mxzmark]

I may have to contact him, thanks. I think I will try my stern mpu-100 in the black jack first, I will just swap over the roms at U2 and u6. Hopefully the issue is not in the roms.

 

[Mxzmark]

Ok cpu swapped and still have the same problem. I think it is safe to say that the problem is a short some place on the playfield or a wire harness someplace. Any ideas on how to narrow this down since I can't find anything on a visual inspection?

 

[Menace]

Not really. These types of issues can be difficult at best to track down. If you could figure out WHERE the voltage might be originating from, like get a voltage reading off the switch it might help you narrow down where to look / trace.

D

 

[Mxzmark]

Troubleshooting done so far. Disconnected cpu connector j4 (switch matrix plug) and checked all pins to ground and also checked the pins on the board ( found no continuity to ground). I have disconnected ( de pinned) every strobe and return line one at a time and checked in switch test with a ball and am still getting multiple switch closures. Interesting note is this- if I have the strobe line removed I still get multiple switch closures on switches in that strobe column but only when I use the ball not my finger. Seems to be the same for all strobes. This is driving me crazy.

 

[Mxzmark]

Troubleshooting done so far. Disconnected cpu connector j4 (switch matrix plug) and checked all pins to ground and also checked the pins on the board ( found no continuity to ground). I have disconnected ( de pinned) every strobe and return line one at a time and checked in switch test with a ball and am still getting multiple switch closures. Interesting note is this- if I have the strobe line removed I still get multiple switch closures on switches in that strobe column but only when I use the ball not my finger. Seems to be the same for all strobes. This is driving me crazy.

Sorry i meant connector j2

 

[Mxzmark]

No fix with J3 removed ( cabinet matrix plug) I jumpered the self test switch on this connector to get into switch test.

 

[Mxzmark]

No fix with J3 removed ( cabinet matrix plug) I jumpered the self test switch on this connector to get into switch test.

No continuity to ground on any of these pins either.

 

[cdnpinballer]

I think it's time for you to invest in a ceramic Powerball. (seriously)

Barring that I would look VERY VERY VERY closely with a bright light at all affected switches again.

I would specifically look at the switches that are affected when you roll a ball over them. It must be a short.

 

[Mxzmark]

That's basically every switch. Lol. I might start removing switches one by one till I find it. What's also strange is that it is showing switch closures that are not even switches in this game. I am determined to find this if I have to take the game apart piece by piece just to say I fixed it. Lol

 

[Mxzmark]

Maybe I should see if I can get some new roms as well.

 

[Menace]

Rom's won't make a difference. You have pretty much ruled out an issue on the PCB, and from what we can tell it's something not quite right under the PF. I wish it was as easy as saying "look here and here" but that's the trouble with pinball sometimes... the answer can be starting you right in the face or it could be buried deep under who knows what. (and I've experienced both scenarios)

D

 

[cdnpinballer]

On your MPU board.... Did you secure it to the backbox brackets with screws (to ground) or just install on the plastic standoffs? Maybe try screwing the board down if not already? I don't know, I am out of ideas except it being time to open up the wiring harness to have a look at spliced wires shorting but even so it wouldn't explain why the switch works perfectly when activated with your finger vs. a steel pinball. Can you maybe post a video of exactly what is happening so we can have a better idea of what you're talking about?