WPC-S Back Box GI Out-FIXED

I'll preface this by saying I'm an electronics Noob . . . Need some help with my WCS backbox GI. Nothing works. The power driver board was just worked on by Clive @ CoinOp Cauldron.

Here is what I've done so far:

-Checked fuses (Pulled them out and checked). All good.
-Looked for broken wires. Couldn't see any.
-Folllowed Pinwiki to check continuity on J120 with Triacs etc. Good.
-Checked voltage J120 . . . see below
-Replaced the female connector at J120 and checked continuity from the connector to the last lights in the back box. Good.

The odd part is that I swapped J120 & J121 and the GI on the playfield worked at J120, but still the backbox GI did not on J121.

Also, when I checked the voltages for all 4 wires on J120 I got .245 or something like that, but when I swapped J120 & J121 and checked voltages I got 6 volts on J120.

I'm not sure where to go next with this. Any ideas?

Thanks in advance,
Greg

_{Post edited by gjbwalker: problem solved}

#2 9 years ago

SMK

TheLaw

Pinside+ Addict

Ann Arbor, MI

12y 162K 48,038 19 30 1

OP
Quoted from gjbwalker:
-Replaced the female connector at J120 and checked continuity from the connector to the last lights in the back box. Good.
The odd part is that I swapped J120 & J121 and the GI on the playfield worked at J120, but still the backbox GI did not on J121.

How aboot the male connector? Are you sure you have continuity from the front of the board/pin to the back of the board traces?

If J120 works with both strings, and J121 works with neither, I might think it's not getting the correct juice to the pins.
EDIT: you have continuity with the female side to sockets, so let's look before that.

#3 9 years ago

GJB

gjbwalker

Pinside member

I'll double check that and report back.

Thanks!

#4 9 years ago

JWJ

johnwartjr

You mention the playfield works on J120 and J121, correct, but the backbox works on neither?

You most likely have a wiring problem.

You may also not be measuring voltage correctly. GI is A/C, so instead of measuring voltage against ground, you measure voltage across 2 pins (supply and return) on the board.

Pins 1 & 7 - Brown String
Pins 2 & 8 - Orange String
Pins 3 & 9 - Yellow String
Pins 5 & 10 - Green String
Pins 6 & 11 - Violet String

#5 9 years ago

GJB

gjbwalker

Pinside member

Law: I haven't had a chance to pull the board and check continuity through the board yet.

John: Correct on the J120/121. How I tested the GI was meter on AC and measured the solid color (I can't remember colors as I'm at work) like yellow on J120 with white/yellow on J120. There were only 4 wires on that connector, so I did the same with corresponding wire combos. Is that correct?

I think I have a picture on my phone, I'll try and post . . .

#6 9 years ago

GJB

gjbwalker

Pinside member

20150218_205524.jpg

#7 9 years ago

JWJ

johnwartjr

Unplug J120 and J121

Measure across all the pairs.

If the yellow pair and the green pair are still lower than the others, work your way back through the board. Check the continuity. Are the fuses good?

If all the continuity tests pass, and the voltage on those pairs are low, you've likely got a GI input problem. Transformer to secondary harness? J115?

#8 9 years ago

IKR

german-pinball

https://forum-s3.pinside.com/201401/1362445/174403.jpg

Mightbe, my grafic can help you:

#9 9 years ago

DMD

DareDevyl

Pinside member

Lake Loon, NS

11y 35,400 127 8

Just an observation but I might be wrong. It looks like the connector to J121 has a couple of wires on the IDC that do not appear to be in that great a shape. Meaning the wires do not appear to be plugged into the IDC very well.

#10 9 years ago

MJS

schudel5

Pinside member

20y 166K 6,392 27

I'd replace that connector housing and connectors that are shown plugged into J121 in that picture. Get rid of that IDC and use crimp connectors.

#11 9 years ago

DMD

DareDevyl

Pinside member

Lake Loon, NS

11y 35,400 127 8

Quoted from schudel5:
I'd replace that connector housing and connectors that are shown plugged into J121 in that picture. Get rid of that IDC and use crimp connectors.

Exactly. As per Clay's guide and many others. Connectors, Connectors, Connectors........

#12 9 years ago

GJB

gjbwalker

Pinside member

Quoted from johnwartjr:
Measure across all the pairs.

Just to be clear John, measure the voltage on the male pin pairs? Pin 3 & pin 9, etc . . . sorry noob here. If not please explain.

Fuses are good.

Quoted from johnwartjr:
If all the continuity tests pass, and the voltage on those pairs are low, you've likely got a GI input problem. Transformer to secondary harness? J115?

I'll ask about this after I check your first test.

Quoted from DareDevyl:
Just an observation but I might be wrong. It looks like the connector to J121 has a couple of wires on the IDC that do not appear to be in that great a shape. Meaning the wires do not appear to be plugged into the IDC very well.

So far everything on J121 works as it should, but will probably replace it.

Quoted from german-pinball:
Mightbe, my grafic can help you:

Thanks!

Learning a lot here everyone . . . thank you!

#13 9 years ago

JWJ

johnwartjr

OP
Quoted from gjbwalker:
Just to be clear John, measure the voltage on the male pin pairs? Pin 3 & pin 9, etc . . . sorry noob here. If not please explain.
Fuses are good.

I'll ask about this after I check your first test.

So far everything on J121 works as it should, but will probably replace it.

Thanks!
Learning a lot here everyone . . . thank you!

Yes, measure the pairs of pins against each other

Do both J120 and J121

One probe on pin 3, the other on pin 9, etc
Check all the pairs

#14 9 years ago

GJB

gjbwalker

Pinside member

Well John I measured J120 and J119 before I pulled the board, but did not do J121. I can put it back in and test again?

Continuity is good through the board at J120/121 and the traces are good. However this is what I got for voltages:

J120:
1&3 7v
2&8 7v
3&9 2.8v
5&10 2.8v
6&11 3.9v

J119:
1&3 3.9v

#15 9 years ago

JWJ

johnwartjr

Open the game and lift the playfield. There's a square connector where the transformer connects to the GI input wires for the driver board. 9 pin square .093 connector. Are any of those wires burnt? The connector housing would be browned or blackened.

#16 9 years ago

IKR

german-pinball

Did I undertand it correct?
You changed the male headers J121 and J120??
Hope, you did not destroy a VIA, because there are traces on the bottom and top of the board.

I would check the continuity again as follows:

A.
J121 Pin 1 to middle pin of Triac Q18
J120 Pin 1 to middle pin of Triac Q18

Same for J121 Pin 2, 5, 6 and J120 Pin 2, 5, 6 and corresponding Triac

See my grafic, you can see all traces on the board.

B.
A.
J121 Pin 7 to fuseholder F110
J120 Pin 7 to fuseholder F110

Same for J121 Pin 8, 9, 10, 11 and J120 Pin 8. 9, 10, 11 and corresponding fuseholder

See my grafic, you can see all traces on the board.

Post the results of you continuity-tests.

C.
But first check the 9-pin connector jahnwartjr mentioned in the post before.

D.
Please make a photo of J115 and post it here.

Cheers

Ingo

#17 9 years ago

JWJ

johnwartjr

It sounds to me like he had Clive @ Coin Op Cauldron repair his driver board. If so, I have nearly absolute confidence in Clive's work - that's why I'm suggesting the 9 pin connector.

#18 9 years ago

IKR

german-pinball

Quoted from johnwartjr:
It sounds to me like he had Clive @ Coin Op Cauldron repair his driver board. If so, I have nearly absolute confidence in Clive's work - that's why I'm suggesting the 9 pin connector.

OOPS, sorry, I did not read this in post 1.

You are absolutly right, the 9-pin connector is often overseen, so that shoul be checked next.

Nethertheless my tip goes towards J115 (femal connector) and/or bad/loose/corroded fuse holders.

#19 9 years ago

GJB

gjbwalker

Pinside member

Ingo, I checked everything you mentioned for continuity and everything was good.

Correct, John, Clive did work on this board and I've never had an issue with his work.

I checked the 9 pin connector and it looks decent. I had reseated it earlier and same result. Here are some pics... Some fuses look bad but I pulled them and they are good.

20150221_111924.jpg
20150221_112152.jpg
20150221_112014.jpg

#20 9 years ago

IKR

german-pinball

OP
Quoted from gjbwalker:
Well John I measured J120 and J119 before I pulled the board, but did not do J121. I can put it back in and test again?
Continuity is good through the board at J120/121 and the traces are good. However this is what I got for voltages:
J120:
1&3 7v
2&8 7v
3&9 2.8v4 and
5&10 2.8v
6&11 3.9v
J119:
1&3 3.9v

These measurments show, that there is someting wrong in the SUPPLY area and not the RETURN area of your GI circuit.

Your GI strings 3, 4 and 5 are not working.

So please measure BACKWARDS from J120/J121 towards the transformer, e.g. from J 120/121 9 to Fuse F108 right side (testpoint 1), then F108 left side (testpoint 2), then to J115 4 (testpoint 3)- same for the other faulty GI-strings.

Put you DMM to VAC, we measure the mentioned test points against ground.

Post the results, we will find the faults, the GI-circuit is pretty simple.

Cheers

Ingo

#21 9 years ago

IKR

german-pinball

OP
Quoted from gjbwalker:
Ingo, I checked everything you mentioned for continuity and everything was good.
Correct, John, Clive did work on this board and I've never had an issue with his work.
I checked the 9 pin connector and it looks decent. I had reseated it earlier and same result. Here are some pics... Some fuses look bad but I pulled them and they are good.

20150221_111924.jpg 537 KB

20150221_112152.jpg 124 KB

20150221_112014.jpg 298 KB

Your J115 female connector, the black one, does not look good, I see there someting burned and/or corroded!!!! I am sure, there is the fault.

You say, some fuse look bad, but are good. BUT how do the fuse holders look like - is there corrosion?? Please clean them!!!

#22 9 years ago

GJB

gjbwalker

Pinside member

Thanks Ingo. I'll get back to you with some numbers. Can I replace the J115 Female connector with the white molex variety?

#23 9 years ago

IKR

german-pinball

OP
Quoted from gjbwalker:
Thanks Ingo. I'll get back to you with some numbers. Can I replace the J115 Female connector with the white molex variety?

Yes, you can. And if possible and you have on hand, use trifurcon contacts!!!

Cheers

Ingo

#24 9 years ago

GJB

gjbwalker

Pinside member

In the end I replaced the J115 female connector as Ingo suggested and that did the trick. Thanks Ingo!

And thanks to everyone else who helped!

Greg

PS You might see another help post as I have an issue with back VUK

#25 9 years ago

IKR

german-pinball