Bally Coil Wiring

dieseldogpi

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OK, so it may seem that I am over posting, and you may be right, but I dont know if it is better to throw a different problem in the middle of another thread, or start a new one. Aside from my GI lighting issue which is in progress, I have a coil issue on Mr. and Mrs. Pacman pin. Flippers work as they should, the only other coils that seem to fire correctly are the kick out holes and a lane diverter, the pop bumpers, lower rubber bumpers, and drop target coils do not seem to be operating correctly. In the test mode, when the other coils should be operating, the coils under the 2 main drop target banks (not the one that resets them, but there are 4 individual coils under each that I guess drop that particular target) just go off randomly.

I took apart one of the drop targets to start replacing diodes and I noticed something. One of the coils only had two lugs and 1 diode. Now I know I read that any of the coils that run off the solenoid expander board need 2 diodes. I checked the other drop target bank and all 4 coils had 3 lugs and 2 diodes. Further more the one diode on the coil in question was def newer, leading me to believe it was replaced incorrectly.
Basically the question is will this cause intermittent coil operation? I don't want to sit here and trouble shoot a phantom issue if I can replace this coil and maybe fix an issue. either way I think I am going to order it, but since it will take a while I might as well get some feedback. Also the numbers on the coils are the same, so they are same.
Below are some pics. Sorry about the long winded post.

DSCF0251.jpg


DSCF0250.jpg
 
well I think i answered my own question. Looking at the manual, 7 out of the 8 coils were one part number, while one was another. So i guess the one coil should only have 2 lugs. So now I'm back to square one. With numerous non-working coils, do I just start replacing diodes and hope for the best?
 
OK, so it may seem that I am over posting, and you may be right, but I dont know if it is better to throw a different problem in the middle of another thread, or start a new one. Aside from my GI lighting issue which is in progress, I have a coil issue on Mr. and Mrs. Pacman pin. Flippers work as they should, the only other coils that seem to fire correctly are the kick out holes and a lane diverter, the pop bumpers, lower rubber bumpers, and drop target coils do not seem to be operating correctly. In the test mode, when the other coils should be operating, the coils under the 2 main drop target banks (not the one that resets them, but there are 4 individual coils under each that I guess drop that particular target) just go off randomly.

If you're getting individual coils firing multiple times in coil test you've got either a PIA at the MPU, wiring or decoder problem on the regulator/driver board. My guess would be that it's a connector issue. I would check continuity of all the connections between the solenoid control PIA on the MPU and the decoder on the regulator/driver. Right from pin to pin checking through sockets, connectors, etc... There will be 4 data lines and a strobe. That's 5 connections to check. I won't be surprised to see no continuity in one of these connections. I've seen that several times.

If the connections between the PIA and decoder are good then you can assume you've got either a PIA or decoder problem and go from there.

We can assume it's more than a simple problem with power or some transistors because the wrong coils are energizing and coils are energizing multiple times during coil test. Assuming I'm reading things right.

I took apart one of the drop targets to start replacing diodes and I noticed something.

Okay... so why were you replacing diodes? Because they're the cheapest and you're hoping they might solve your problem? If so, stop doing that immediately and completely remove that method of troubleshooting from your toolbox. The "replace what's cheap" method is probably the worst thing you can do. Your goal should be to never be guessing as to the cause of the problem. And NEVER be dropping in parts without at least knowing why and how it might solve your problem. I realize that's easy to say and until you've got a shit-ton of experience there's going to be some guessing but try to keep it within reason ;)

do I just start replacing diodes and hope for the best?

Definitely not.
 
We can assume it's more than a simple problem with power or some transistors because the wrong coils are energizing and coils are energizing multiple times during coil test. Assuming I'm reading things right.
Yes, you are reading it 100% right.


Okay... so why were you replacing diodes? Because they're the cheapest and you're hoping they might solve your problem?

Basically, and obviously this method has not helped me out so far.

I am going to check the continuity later tonight and I will report back. Thanks again Lindsey.
 
I took a look at the schematics for you. Theses are the connections I would check, from PIA pin on the MPU to decoder pin on the regulator/driver board:

PIA (U11) -> 74L154 decoder (U2)
10 - 23
11 - 22
12 - 21
13 - 20
19 - 19

If those connections are good I would see what the input pins on the decoder are doing with a logic probe during solenoid test. If something is stuck high or low you need to figure out why (possibly a PIA problem). If the signals going into the decoder on the regulator/driver look good you can assume that there is a problem with the decoder. I would still bench test it to be sure.
 
You are an incredible help...thanks. I am definitely hoping it is a continuity issue, because then it could be a quick fix, but I highly doubt it will be as I had someone go through the board, so I'm guessing it will be PIA problem. But then again none of my guesses have been remotely correct so we will see. I will report back with my findings and thanks again.
 
At this point it really has to be connectivity somewhere. I went over both his solenoid driver and MPU and both played 100% before they were sent back. Need to start thinking system issue rather than board issue.

Chris
 
At this point it really has to be connectivity somewhere. I went over both his solenoid driver and MPU and both played 100% before they were sent back. Need to start thinking system issue rather than board issue.

Chris

I figured it would be a connector issue too. If the boards are known good that makes it even more probable. Like I said, I would check continuity thought the harness as described above.
 
System issue meaning the PIA?

No. The PIA(s) - "Peripheral Interface Adapters" are the two BIG chips in the center middle and bottom of the main board. They literally are the "translators" that allow data between the brain (CPU) and the external world (switches, solenoids, etc.) to be understood.

SYSTEM means "anything besides boards" (wiring/harnesses/connectors/etc.).

Chris
 
OK, so I checked the continuity with my meter, using the resistance feature. Using the attached chart from the pinrepair guides.
I checked from U11 to plug J4, the correct resistance was there, I also checked from pin to pin on U11 to U2 on the regulator board and the correct ohms were present there. When checking from plug to plug, there was no resistance, reading went down to 0, so seemed god there. So now I should check the PIA's? I have a logic probe, although I am very new to this stuff and I have no idea what I'm doing (obviously). I also checked the dip switched on the board, which some seemed to be incorrect in comparison to the manual, but this made no difference. So what next?
 

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