Skateball (MPU) resistor TECH

[tomdotcom]

I actually have a solenoid driver board coming from a friend. I'm going to try it and maybe it's got something to do with that.

I was having problems with the flipper relay before the pin died. The flippers coils would only activate if you held the flipper relay in manually.

Probably totally unrelated to my power problems though...

[tomdotcom]

Ok I traced all the wires by hand and using the schematics. All the
wires line up for connector J3 on the transformer board going to the
all the other boards. Except for one exception.

I have the transformer wire from a2j3-13 going to Solenoid Driver
board a3j3-5. The plug connector schematic says its supposed to go
from a2j3-13 to SOL. BUSS

I have no wire at a2j3-9. The plug connector schematic says its
supposed to go to a3j3-5, a8j1-9.

Thoughts? Would this cause my issue possibly?

[tomdotcom]

From the sounds of it those 2 wires go to the same spot...back to the backbox to figure this out..wish i was better with the multimeter so I knew where to test things BEFORE frying stuff haha

[Strangeways]

Sounds like you have your Yellows mixed up. If you check the schematic - you will see a color chart down the bottom.

A2 J3 13 Solenoid BUSS is a Yellow/White wire (53)

A2 J3 9 to A3 J3 5 is a Yellow wire (30)

re check A2 J3 - that's where your issue is and then double check with a multimeter.

[tomdotcom]

Ya it's a yellow wire, but I was told from another friend up here that it's not the issue as they both are 43vdc and go to the same place...

[tomdotcom]

I don't have a yellow/white wire whatsoever....not sure if that's normal. But that shouldn't cause my issue anyhow from the sounds of it...

[tomdotcom]

I did see the color chart :) I have traced all the lines by color as well as by using the schematic plug connector chart.

Here's one of the answers I got:

Nope, not it ... but keep tracing.
A2J3-9 and A2J3-13 are the exact same signal on the rectifier board -- both are 43V out from the rectifier board. One goes to solenoid bus, other goes to relay (A3J3-5). If the two wires are reversed, it won't matter as they both come from the same place. However, for sake of tracing the machine at some later date - best to put the wires where the manual says they should be.

To me - it still sounds like a short between A3J3-5 and A3J3-6... somewhere. Not necessarily a short at the connector but somewhere in the wiring.

[tomdotcom]

Ok I installed a different SDB in the pin and tested at all the test points on the SDB,MPU,and rectifier board. The machine works great now and all test points tested perfect on all 3 boards. Everything works perfect, except for the flippers don't work. The flipper buttons work fine however, just the coils won't fire.

 All the other solenoids work and I am getting 43vdc to the flipper coils. I replaced q15 xsistor on the SDB and that didn't help. I can get the flipper relay to pull in when I ground q15, but that's it. Ideas???

I also checked the diode buy the flipper relay and it tested perfect..

Not sure what to try next???

[Strangeways]

Ground the center lug on the flipper coil - if it fires, you have a bad ground. check the ground strap from the head to the body. Make sure the SDB has two screws grounding it out.

Check the EOS - must be adjusted to "normally closed" - Clean and regap if necessary

Check the flipper cabinet switches - file and adjust

Check J1 on the SBD and the relay - look for dry joints.

[ajlaird]

What's the trick for testing a coil with a battery? Would it be worth trying in this instance?

[ddstoys]

If grounding out the Transistor works it sounds to me like the pre driver isnt pulling in the main transistor.

[Strangeways]

What's the trick for testing a coil with a battery? Would it be worth trying in this instance?

I think the coils are ok in this instance.

Can be confirmed if a third SD was obtained and tested.

[tomdotcom]

Going to do some more troubleshooting tonight thanks for the suggestions guys. I know when I first got it that they had the flipper relay jammed in and the game played fine. So the coils do work fine. The SDB is a known working board so all the components should be fine. I must have something wrong with a connector or possibly in the U11 chip. I'll post more when I do some more testing. So close but yet so far away haha..

[tomdotcom]

If I ground q15 on the SDB the flippers fire just fine.

[ajlaird]

If I ground q15 on the SDB the flippers fire just fine.

Excellent, you should be able to work back from there.