Bally Black Jack switch matrix issue

[cdnpinballer]

Double check the diodes on those roll over switches.

 

[Mxzmark]

No the guides on the sides are plastic.

 

[cdnpinballer]

And others that could be causing the problem.

 

[Mxzmark]

I may have to check them but it's strange that they would all go. This is happening with all the rollovers. They are on different strobes and returns. This is a strange one!

 

[cdnpinballer]

I would check all the diodes in the problematic chain(s).

 

[Mxzmark]

Just clipped and tested all the diodes, they all check out fine.

 

[cdnpinballer]

Look very closely at all the switches on the problematic chain. Are they shorting to anything?

 

[Mxzmark]

I have checked every switch in the game and have found nothing shorting or touching them. The only other thing I have done ( that I haven't already undone) was rebuild the rectifier board. It got new rectifiers, header pins and did all the mods to it that were recommended on pinrepair.com. Maybe something got screwed up there that is causing this. All the voltages checked out fine at all the test points though

 

[cdnpinballer]

Did you do any connector work?

 

[Menace]

What I'm having trouble wrapping my head around is the fact the issue doesn't present itself when you use your finger to trigger the switches but when you use the metal ball it goes nuts...

D

 

[cdnpinballer]

Agreed, doesn't make sense.

 

[Mxzmark]

No connector work was done , just the header pins on the rectifier board. I agree it makes no sense but that's what is happening, I'm thinking of swapping in the transformer and rectifier board from the Stern Stars to see if the issue goes away, I think it is interchangeable.

 

[cdnpinballer]

Go ahead and try it but I personally don't think your problem is a result of anything on the rectifier board because you already stated that voltages are on spec and that's all the rectifier board does - convert and transfer voltage to other boards. It's the entry portal for power only. No logic interpreted on that board.

 

[Menace]

Yep. I highly doubt its the rectifer pcb. If you have a DMM, toss the black on the side rail and put the ball on the switch and red lead on the ball. See if you get any voltage for giggles.

This is a weird one.

D

 

[cdnpinballer]

If no voltage is measured on the ball and the problem still persists I think you should go back and double check what Sylvain initially said about the MPU's J2 and J3 connectors. Re-flowing solder on the header pins is good but re-pinning the female pins inside the connector housing may solve your problem. Before doing that however, I would cross reference the wiring diagram schematic vs. the wiring in your machine to make sure each wire is on the correct pin. Maybe a previous owner messed up? Still doesn't explain why the issue is intermittent with your finger vs. ball though. Maybe you have a haunted pin?

 

[Mxzmark]

Ok when I measure from the ground panel in the backbox to the metal roll over switches ( the part the ball contacts) I get between 1 and 2.5 volts A/C.

 

[sylvain]

Does the issue go away if you remove the two General Illumination (6.3V lamps for playfield and backbox) fuses ?

 

[Mxzmark]

I will try that when I get home. Had to go out of town for a few days for work. I will keep you all posted.

 

[Mxzmark]

Ok I pulled the fuse for the a/c gi lighting and the problem still remains. The troubleshooting continues.

 

[Mxzmark]

Swapped in a different transformer and rectifier board, no fix.