Bally Displays Flickering Caused by Back Box Wiring

Have owned my Xenon for 16 years and in that time I opened the back box maybe 5 times. It's been trouble free. Just installed a new playfield and lost all the displays. I was missing voltage at the SDB with good power at the rectifier board so I figured it was time to re-pin all the original connectors. After that my displays are very erratic. However I realized the issue in the wiring around the hinge on the display board. If I jiggle it the displays react. Anybody experienced this? Fixes? Is it best to replace the molex plugs first? The connectors to the displays are all original as well. The idea of opening all those wiring looms to examine every wire is daunting.

#2 6 years ago

DAV

wayout440

Pinside member

OP
Quoted from tomdrum:
Have owned my Xenon for 16 years and in that time I opened the back box maybe 5 times. It's been trouble free. Just installed a new playfield and lost all the displays. I was missing voltage at the SDB with good power at the rectifier board so I figured it was time to re-pin all the original connectors. After that my displays are very erratic. However I realized the issue in the wiring around the hinge on the display board. If I jiggle it the displays react. Anybody experienced this? Fixes? Is it best to replace the molex plugs first? The connectors to the displays are all original as well. The idea of opening all those wiring looms to examine every wire is daunting.

Did you repin the boards as well as the connectors? I'd be suspicious of a cracked male pin or a poor crimp on one of the female connectors before an internal wire break. Once those are confirmed as not the problem, It'd be time to dig out the meter and check resistance on single wires while opening and closing the door. Hopefully you could isolate a single wire before having to replace a section of harness.

#3 6 years ago

TPD

tomdrum

Quoted from wayout440:
Did you repin the boards as well as the connectors? I'd be suspicious of a cracked male pin or a poor crimp on one of the female connectors before an internal wire break. Once those are confirmed as not the problem, It'd be time to dig out the meter and check resistance on single wires while opening and closing the door. Hopefully you could isolate a single wire before having to replace a section of harness.

It's currently running a newer Alltek MPU and SDB. I sent the OE boards out to be upgraded. I did re-crimp the J3 SDB #6 & 8 a 2nd time just to be sure. They're HV connectors.

#4 6 years ago

DAV

wayout440

Pinside member

Are you sure you are losing HV? Whenever I had had flaky displays where all are erratic as the door is opened it is usually the connector at the MPU that is problematic. Did you repin J2 connector to the MPU board?

#5 6 years ago

TPD

tomdrum

Quoted from wayout440:
Are you sure you are losing HV? Whenever I had had flaky displays where all are erratic as the door is opened it is usually the connector at the MPU that is problematic. Did you repin J2 connector to the MPU board?

All the MPU connectors re-pinned except the J4 at this point. HV is present at the SDB. The Alltek has a LED for the 180VDC and a TP for 240. Checked with a meter and both are correct. Was hoping to have this thing fixed before Thanksgiving so my guests can enjoy the new playfield.

#6 6 years ago

DAV

wayout440

Pinside member

OP
Quoted from tomdrum:
All the MPU connectors re-pinned except the J4 at this point. HV is present at the SDB. The Alltek has a LED for the 180VDC and a TP for 240. Checked with a meter and both are correct. Was hoping to have this thing fixed before Thanksgiving so my guests can enjoy the new playfield.

Dunno, kind of running out of suggestions....can the symptom be repeated, duplicated - perhaps post a video of what you are seeing?

#7 6 years ago

TPD

tomdrum

Quoted from wayout440:
Dunno, kind of running out of suggestions....can the symptom be repeated, duplicated - perhaps post a video of what you are seeing?

After fiddling with this I think it's in the J1 on the MPU. When I move the connector the working displays will flicker. Only have player 2 & 4 lighting at all. I did replace all the pins and the housing. Rechecked all the wires per the schematic and the only discrepancy I see is pin 26. Schematic shows a Blue/white, mine is Green/blue. There isn't a blue/white anywhere in that connector.

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#8 6 years ago

DAV

wayout440

Pinside member

As long as your green/blue carries over to pin 18 of each of the displays I think you are alright. Seems like a color substitution for whatever reason.

Anyways, if your moving something by hand and it causes a reaction in the displays it's going to be some kind of loose connection, possibly a bad crimp.

#9 6 years ago

TPD

tomdrum

http://www.pinrepair.com/connect/#good

I bit the bullet and re-pinned the entire J1 again. Went slowly and carefully. Now I'm missing the 1st digit on every display. On test mode the credit displays shows zero's in some digits. Heading to the liquor store now.....

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#10 6 years ago

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ForceFlow

Pinside Moderator

9y 238K 31,369 268 14

Are you getting good crimps?

#11 6 years ago

TPD

tomdrum

Quoted from ForceFlow:
Are you getting good crimps?
http://www.pinrepair.com/connect/#good

I think so. I've done 4 other games over the years. Difference is that I'm using the white cheaper housings from GPE, didn't have the .100 brown ones I'm used to using. The connectors seem to "click" in place just fine.

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#12 6 years ago

TPD

tomdrum

http://stevekulpa.net/pinball/bally_disp6.htm

Found some great info here:

J1 on the MPU pins 1-7 control digits 1 to 7. Re-pinned #1 (3rd time!) now it's working. Ironically Steve used to do all my board repairs.

#13 6 years ago

DAV

wayout440

Pinside member

OP
Quoted from tomdrum:
Found some great info here:
http://stevekulpa.net/pinball/bally_disp6.htm
J1 on the MPU pins 1-7 control digits 1 to 7. Re-pinned #1 (3rd time!) now it's working. Ironically Steve used to do all my board repairs.

Good! Are you saying you repinned the board, or the cable connector? If it is the cable that was troublesome, are you cutting back some of the old wire when you go to repin? You should be cutting back at least 1/2 in to an inch if there is enough slack in the cable.

#14 6 years ago

TPD

tomdrum