(Topic ID: 263415)

Bally Paragon Switch Matrix Issue


By tomdrum

86 days ago



Topic Stats

  • 16 posts
  • 5 Pinsiders participating
  • Latest reply 83 days ago by frunch
  • Topic is favorited by 2 Pinsiders

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#1 86 days ago

Fixing up a Paragon. I have 3 switches not working, center pop bumper, top center target and right outlane. Those 3 are shown in the switch matrix as connected thru the A4-J2 pin 13 brown wire / yellow trace. During a solenoid test the pop bumper fires. I repined the MPU J2 connector and ran a continuity test between the outlane switch and the connector, it was good. I repined that pin 2 more times just to make sure I didn't have a bad crimp. Game is running an Alltek MPU and just to be sure, I pulled another Alltek MPU from my other fully working Paragon and problem still exists. So the issue isn't MPU board related.

I'm stumped at this point, suggestions appreciated.

#2 86 days ago

If all three switches are in the same column or row, you need to check all switches in that column or row. One could have a broken wire or disconnected wire. It may not be one of the three; it could be a working switch, so check them all.

#3 85 days ago

Checked every single switch, all look good. Changed every diode and cap on the non working switches. Still they don't work. Checked all switches to make sure none were grounded. Pulled the MPU J2 and checked pin 13 (switch return for that row) to ground. It's not grounded.

Read a previous Quench post and pulled the MPU J3 with the game running and they don't work.

#4 85 days ago
Quoted from tomdrum:

Checked every single switch, all look good. Changed every diode and cap on the non working switches. Still they don't work. Checked all switches to make sure none were grounded. Pulled the MPU J2 and checked pin 13 (switch return for that row) to ground. It's not grounded.
Read a previous Quench post and pulled the MPU J3 with the game running and they don't work.

I'm not sure what you mean by your last sentence, but have you checked connectivity from every switch along that line between the switch lug and the connector in the backbox? If not, I would try that next. I'm still thinking there's a broken wire somewhere.

#5 85 days ago
Quoted from tomdrum:

Read a previous Quench post and pulled the MPU J3 with the game running and they don't work.

I went back and read a bunch of previous Bally switch matrix threads and @quench suggested that to check wiring.

#6 85 days ago

All 3 non-working switches have good continuity to the MPU.

#7 85 days ago

Hi tomdrum
What's happening in switch test mode with those switches - are any responding or claiming to be stuck closed?

#8 85 days ago

Thanks Quench, appreciate your help.

All switches register on the test except the non working 3. None register as closed when normally open. Non working switches are right outlane, top center target, center pop bumper, I5 row on matrix.

Per previous threads I checked for grounded switches, Didn't see any.

#9 85 days ago

Somethings not making sense. So, it isn’t the MPU because you tried different boards. And, all three switches have perfect continuity to the connector on the board.

Have you checked the switches themselves? Are they gapped correctly? If you hold them closed, do you have continuity from one lug to the other?

#10 85 days ago
Quoted from tomdrum:

Those 3 are shown in the switch matrix as connected thru the A4-J2 pin 13 brown wire / green trace.

Just out of curiosity, the manual states A4-J2 pin 13 is a brown-yellow wire (not brown-green). What's the wire colors on your other Paragon at that pin?

#11 85 days ago

They are both brown/yellow, my 1st post was incorrect.

#12 84 days ago

Your problem is with I5, the 63 wire, brown yellow, originating at the MPU J2-13. Are you sure you carefully examined this wire thoroughly from the MPU connector onward? It's either a board problem or more likely there is a break somewhere. I would start by turning the MPU over and reflowing the J2 connector. Then I would run a temporary bipass wire from pin 13 to one of the switches and see if that return row starts working. If it does pull the wire out of the harness and find the break.

It's also possible the 6821 chip is bad, As a last resort swap U10 and U11. Hows the condition of the board? Any battery acid damage?

#13 84 days ago
Quoted from BigAl56:

Are you sure you carefully examined this wire thoroughly from the MPU connector onward?

I ran a continuity test from each switch to the MPU connector pin and it was good.

Quoted from BigAl56:

Hows the condition of the board?

It's running an Alltek and just to be sure I installed a 2nd Alltek, so the board isn't the issue.

#14 84 days ago

It's fixed. How I don't know. I was checking continuity thru the switch leafs, and now it works.

#15 84 days ago
Quoted from tomdrum:

It's fixed. How I don't know. I was checking continuity thru the switch leafs, and now it works.

Maybe a bad solder joint on one of the lugs with the wire. Perhaps it got pushed back in place when you were messing with the switches. If it reoccurs, you may want to reflow the solder on all the switches.

#16 83 days ago

Also check near the solder lugs for each switch in that circuit, make sure the solder lugs and diodes on the switches aren't contacting any adjacent solder lugs from other switches and lamps nearby. I had a hell of a time diagnosing a weird switch problem that wound up being a solder lug for a lamp was really close to a switches solder lug. It was kinda buried under wiring and stuff, took a while to find it. If the problem persists, that's where I'd start looking. Also, make sure to replace the switch caps on any other switches that use them in the game, not just the ones in that circuit. There's often one for the tilt bob on the side of the cabinet too. Good luck, Paragon is an awesome game!

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