(Topic ID: 161656)

WCS shorted low voltage and high voltage, need help with next steps


By EvanDickson

3 years ago



Topic Stats

  • 24 posts
  • 5 Pinsiders participating
  • Latest reply 3 years ago by MeEtc
  • Topic is favorited by 3 Pinsiders

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IMG_20160628_1758139[1]_(resized).jpg
10-opto.jpg
WizardHat.jpg
u20_u23.jpg
20160607_203247_(resized).jpg

#1 3 years ago

I shorted the switch matrix to the high voltage by nudging a loose wire on the free kick switch into an adjacent coil terminal. I've made some progress, but the circuit diagrams in the WCS manual (as taken from IPDB) are pretty slack and I've hit a wall. Can anyone provide guidance and/or point me to schematics for WCS?

So far:

1. I started with a 'check f114 and f115' error (fuses were ok).
2 I replaced U20 and was able to get past that error. Now I have 'gnd short row 1 stuck closed'. Tests report that rows 1, 2, and 3 are all stuck closed.
3. I replaced U18, and rows 1, 2, and 3 still report stuck closed.
4. I replaced U14 and still have reports of ground short row 1, 2, 3.
5. If I unplug the 10 opto board, the errors are not reported. However, if I swap in a different 10 opto board, they are still reported, so I don't think the 10 opto board actually has any issues.
6. If I unplug the 7 opto board, the ground shorts are still reported, so I don't think the 7 opto has issues.
7. Based on pinwiki, ~13.3V AC at J101.4 and J101.7, 17.2V DC at TP8, and 12.0V DC at TP3 are all ok.
8. Based on pinwiki, voltages at some pins of J207 and J209 are NOT ok (I have listed them below), if I understand correctly and they should all be about 12V.

All this leaves me thinking the issue will lie in the in the driver board, probably some baked IC and / or burned transistors, but without schematics, I'm not sure which ones.

Voltages found in J207, 209:

J207.1 = 10.9V
J207.2 = 10.9V
J207.3 = 12.0V
J207.4 = 12.0V
J207.5 = 0.7V
J207.6 = 0.7V
J207.7 = 0.7V
J207.8 = NA
J207.9 = 0.7V
J207.10 = 10.8V
J207.11 = 10.5V

J209.1 = 11.7V
J209.2 = 11.8V
J209.3 = 11.8V
J209.4 = 10.7V
J209.5 = 11.6V
J209.6 = NA
J209.7 = 11.6V
J209.8 = 11.6V
J209.9 = 11.6V

Thanks!

#2 3 years ago

Daytime bump. Anyone know if schematics for the power board exist? I'm guessing when I see stuff like the white powdery blowout on this IC (U11), it's bad. But not all bad things are visible, and I don't know which IC to check / replace.

20160607_203247_(resized).jpg

#3 3 years ago

Here's the schematics. They're WPC, not WPC-S, but won't matter for what you're doing.

http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Williams%20WPC%20DMD%20Schematics%2016-9473.pdf

Do you have a logic probe?

#4 3 years ago
Quoted from terryb:

Here's the schematics. They're WPC, not WPC-S, but won't matter for what you're doing.
http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Williams%20WPC%20DMD%20Schematics%2016-9473.pdf
Do you have a logic probe?

Thanks Terry! I have a logic probe. And even a usb oscilloscope, if needed.

#5 3 years ago

Have a look at the following article. I use the switch matrix as an example. Either the scope or the logic probe will work. I prefer the scope, but that's just what I'm used to using on the bench.

https://pinside.com/pinball/forum/topic/terrybs-guide-to-logic-probes

#6 3 years ago

At the moment I'm 2 weeks without schematics and other pictures but I've seen multiple times that after a short between solenoid power and switch-matrix on a wpc-s board, the drive ic for U20 -the bcd to 16 encoder 74hc4514- also was blown.

That's all help I can give now

#7 3 years ago

An interesting update. The power board in my WCS is a 12697-1. I hadn't previously swapped in the power board from my NF, because it is a -3 and I didn't know if they were compatible. I noticed while trying to figure out the schematics here that the correct board for the WCS is the -3. I guess they are compatible. So I swapped power boards and still have the grounded rows.

So my next step is to replace the CPU chip mentioned by zaza (it's U23). This one wasn't mentioned in the pinwiki, so I hadn't replaced it. Another order to GPE, Ed's probably getting tired of me.

Hopefully that will clear up any CPU issues, which apparently still exist.

And then with any luck the power driver board will actually be ok (I'm assuming that I'll still have to do work on it too though).

I understand how to use a logic probe now Terry, thanks. The instructions on how to interpret the lights made perfect sense. Not sure yet how to apply it to actually troubleshooting, but I'll do some playing around with it and see what I can see.

2 weeks later
#8 3 years ago

In case it is still needed, I had some time to make a picture from U20 and U23 in wpc-s CPU.

- U23 Inputs A0, A1, A2, A3 generates 16 pulsing outputs, colored in green numers 1-8. (9-16 are not used)
- These are directly connected to the inputs of U20.
- Black numbers 1-8 are driving J206.

check the green numbers on U23 with a probe, they should be pulsing at ~1700 Hz

u20_u23.jpg

#9 3 years ago
Quoted from zaza:

In case it is still needed, I had some time to make a picture from U20 and U23 in wpc-s CPU.
- U23 Inputs A0, A1, A2, A3 generates 16 pulsing outputs, colored in green numers 1-8. (9-16 are not used)
- These are directly connected to the inputs of U20.
- Black numbers 1-8 are driving J206.
check the green numbers on U23 with a probe, they should be pulsing at ~1700 Hz

Thanks Zaza, it turned out that replacing U23 did the trick. A couple other damaged components, but this was the main issue. What you advised isn't even documented on pinwiki, I think you've earned a wizard hat.

#10 3 years ago

Glad it worked out by replacing U23. Pinwiki is of course free to use the picture above. If any suggestions for the picture, let me know.

Quoted from EvanDickson:

I think you've earned a wizard hat.

Thanks, added to the trophies

WizardHat.jpg

#11 3 years ago

Hello zaza, I'm the new owner of the WCS in question, thanks greatly for your assistance.

I've encountered another issue, which I'm unsure is related or not. The opto for the TV award VUK is stuck closed as shown on switch edge tests. There is a Great Lakes Modular 10 opto board installed that has indicator lights for each emitter and receiver. The indicator lights are showing the opto pair is working, but the change is not being sent into the switch matrix. Unplugging the header does open the switch on the matrix.

#12 3 years ago
Quoted from MeEtc:

Hello zaza, I'm the new owner of the WCS in question, thanks greatly for your assistance.
I've encountered another issue, which I'm unsure is related or not. The opto for the TV award VUK is stuck closed as shown on switch edge tests. There is a Great Lakes Modular 10 opto board installed that has indicator lights for each emitter and receiver. The indicator lights are showing the opto pair is working, but the change is not being sent into the switch matrix. Unplugging the header does open the switch on the matrix.

Optos are normally closed switches.

#13 3 years ago
Quoted from pincredible:

Optos are normally closed switches.

Right, I understand this, but the switch is not opening on the switch matrix when a ball is present. The opto board IS showing the ball presence, but its not being outputted to the matrix

#14 3 years ago

Check for continuity between the row wire (wht-grn) for that switch and another switch in the same row. Do the same for the column wire (grn-yel). Here's a link to the switch matrix if you don't have it.

http://www.pinballrebel.com/pinball/cards/Tech_Charts/Bally_World_Cup_Soccer_Tech_Chart.pdf

#15 3 years ago
Quoted from MeEtc:

I've encountered another issue, which I'm unsure is related or not.

Difficult to say if it is related or not. Best is to check all switches and if it is only this 'TV award' VUK, it is likely only the opto.

A quick test is to short the 'c' and 'e' on the blue receiver pcb at the VUK. I know the GLM 10-optoboard reacts different to this as the original 10-optoboard but at least you know it responds -or not-.
2nd test is with (photo)camera and see if the ir-LED on the green PCB is lit. Also here different as the original as it is pulsing at high speed.

Maybe GLM knows better ways to test the 10-opto PCB and connected optos

#16 3 years ago
Quoted from terryb:

Check for continuity between the row wire (wht-grn) for that switch and another switch in the same row. Do the same for the column wire (grn-yel). Here's a link to the switch matrix if you don't have it.
http://www.pinballrebel.com/pinball/cards/Tech_Charts/Bally_World_Cup_Soccer_Tech_Chart.pdf

Can confirm there is continuity on both row and column wires. Tested continuity to other known working leaf switches. There's 5 optos on the board that all share the column and the other 4 work.

#17 3 years ago
Quoted from MeEtc:

Can confirm there is continuity on both row and column wires. Tested continuity to other known working leaf switches. There's 5 optos on the board that all share the column and the other 4 work.

Then I'd go with what zaza suggested. You can also use a tv remote to test the receive opto (I haven't specifically tried that on WCS, but it works on other pulsed games like the long opto on BSD).

#18 3 years ago
Quoted from zaza:

Difficult to say if it is related or not. Best is to check all switches and if it is only this 'TV award' VUK, it is likely only the opto.
A quick test is to short the 'c' and 'e' on the blue receiver pcb at the VUK. I know the GLM 10-optoboard reacts different to this as the original 10-optoboard but at least you know it responds -or not-.
2nd test is with (photo)camera and see if the ir-LED on the green PCB is lit. Also here different as the original as it is pulsing at high speed.
Maybe GLM knows better ways to test the 10-opto PCB and connected optos

The IR LED is working, confirmed with a camera. The receiver when shorted does change the status LED on the opto board. Moving the opto pair in and out of alignment also changes the status LED. Pulsing with a TV remote also works and pulses the status LED. None of these changes triggered anything on the switch matrix edge test. I'm guessing there's something wrong on the GLM board?

#19 3 years ago
Quoted from MeEtc:

I'm guessing there's something wrong on the GLM board?

If a diode on J3 from Wht-Grn to Grn-Yel does trigger sw#45 in the switch matrix test, the 10-optoboard is likely the problem.
(Also perform this test with J3 disconnected and put diode into the IDC)

10-opto.jpg

#20 3 years ago

Doing this with J3 connected does nothing, a its already stuck closed. Triggering it with J3 unplugged with a diode in the connector triggers the switch on edge test as expected. testing continuity on the opto board with J3 unplugged shows there is about 1k resistance across those 2 pins, but nothing on the others.

I guess this confirms something is bad on the board.

#21 3 years ago

So, the GLM registers that opto is open and closed but doesn't transfer to switch matrix. And switch matrix is tested OK by diode.
Yes, it looks like the 10-optoboard has a problem.

#22 3 years ago

I'm trying to use my Google-fu, but can't find any technical information for the OSB-10A online, not even simple installation instructions. Is there any documentation at all for this board?

Doing continuity and resistance probing, it looks like Q22 on the board is at fault. Markings read A8F. Since only 8 channels on this board are being used, could I not swap the bad transistor to one of the ones not being used?

IMG_20160628_1758139[1]_(resized).jpg

#23 3 years ago
Quoted from MeEtc:

Doing continuity and resistance probing, it looks like Q22 on the board is at fault. Markings read A8F. Since only 8 channels on this board are being used, could I not swap the bad transistor to one of the ones not being used?

Worth a try, but I have absolutely no information of this board.

#24 3 years ago

Mission success! I moved Q24 over to Q22 and the kickout opto is working correctly. but damn those things are tiny!

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