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Gottlieb System 3 Switch matrix issue ********** RESOLVED **********

russdx1

russdx1

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russdx
I have a shaq attaq with what I believe is a switch matrix issue.

Basically when a switch on row 1 is triggered it will trigger all other switches on that column. All other switches on the column (row 2 to row 12) work as expected.

Iv checked the diodes and they are ok. I cant quite work out if it’s a short or bad chip on MPU board? What would cause this sort of behaviour? Deffo seems linked to row 1 of the switch matrix though as all those switches are affected.

Example if I trigger service door switch then, spinner, drop target 4, drop target 5, bottom left target, bottom right target etc… all trigger as well. But spinner etc.. will trigger perfectly by themselves.


It’s like row 1 is shorted or the strobe is stuck? I read the lamps share same stobes as the switches but they all work ok.

Any ideas where to look would be appreciated :)

IMG_0544.jpeg
 
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This is my exact issue, I’ll try the A3J4 trick next, but did not see any odd lamp issues and each lamp lights individually. It did have all sorts of lamp issues previously when LEDs was installed but I removed those and back to nice normal lamps.

IMG_0545.jpeg
 
Removing A3J4 did not fix the issue, Iv noticed lamp 80 causes lamp 81 to slightly glow as well so must be fault with that socket. But removing A3J4 would of isolated that issue?

I went around and removed all the switches off row1 I could find ie door loom, vary target loom, drop target loom. Pretty much just leaving front door / start button & spinner left and the issue is still there.

Starting to think it’s issue with driver board? But if the strobes was not working correctly surely the lamps would be doing funny things on lamp row 1?

Only things on lamp row 1 is shoot again and the start button. Saying that the start button won’t light in single lamp test but does in all lamps flash, shoot again behaves ok.
 
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********** RESOLVED **********

Ah I lied, the start button was not lighting in all lamp test or individual, I unplugged one connector and its fixed the switch issue yay!

Tested its diode and that was fine, so just plugged the connectors the other way way round and now it works in test mode as well and switches all good, so the problem was start button was just wired up back to front (probably when it got converted to led) and its diode caused issues on the matrix, One thing I don't get is, according to pinrepair removing A3J4 should of isolated this lamp issue from the matrix and then i would of looked into the lamps a bit more, but it did not....
 
Only just seen this but I had this exact issue on a SF2 years ago and I was kicking myself trying to diagnose a fault on the CPU and it ended up being the start button contacts too. Very frustrating but top detective work 👍🏻
 
MajesticPinball said:
Only just seen this but I had this exact issue on a SF2 years ago and I was kicking myself trying to diagnose a fault on the CPU and it ended up being the start button contacts too. Very frustrating but top detective work 👍🏻
Click to expand...
Yeah the clues was there with start button not working properly in lamp test. But I ignored! Thinking how lamp could cripple switch matrix.
 
russdx1 said:
Yeah the clues was there with start button not working properly in lamp test. But I ignored! Thinking how lamp could cripple switch matrix.
Click to expand...
Gottlieb system 3 games have a shared lamp & switch matrix. It's a bit of a strange design but the switches and lamps both share the same strobe lines, it's just the returns that are separated so it can be quite common for a bulb holder to cause a switch issue or a switch fault to cause lighting issues.
 
MajesticPinball said:
Gottlieb system 3 games have a shared lamp & switch matrix. It's a bit of a strange design but the switches and lamps both share the same strobe lines, it's just the returns that are separated so it can be quite common for a bulb holder to cause a switch issue or a switch fault to cause lighting issues.
Click to expand...
Indeed, the Pin repair guide suggests removing the A3J4 would isolate the lamps from the switches but did not remove the issue for me, maybe that just isolates the returns and not the strobes?
 
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