The connector on those GI circuits is often toast, that's where I'd start. May have to replace or at least reflow the solder on the pins. It's the primary reason I converted the GI on mine to LEDs.

Did you pull the fuse to test it? It will always read good in the fuse holder.

GI connectors are typically burnt up. Check those first.... and fuses.

I had a burnt J120 (GI in the head). I had to remove the fried pins on the end and replace them and I lost a solder pad and had to improvise (thanks Cheddar for the help!). Then I had to make new connector. If you take board out, test continuity between the pins and where they lead to ensure the pins have a good connection to the board.

20160226_164420_(resized).jpg

It would be worth trying to measure between pins 6 and 11 but since none of the lights are working and you have continuity through the string I think it's pretty safe to say it will measure 0. Try checking continuity from pin 6 back to the triac that controls that string (Q12), if that's there and you have continuity between pin 11 and F106 your connector is good and you'll need to check to see if the triac is bad, is not getting source voltage (bad solder joint, etc.) or is not getting it's gate voltage from the Q11 circuit.

Here ya go...everything you need to diagnose the problem.
After reading this let us know what you find.
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#General_Illumination_Problems
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Teach a man to fish......

You have an option to mark this thread as resolved, fyi...

Not sure if I should resurrect this old thread or start my own but the symptoms were the same.

I've tried all the points made above, but I'm having the same issue with my GI in the J121-11 and J121-6 line. I have new connectors and pins, and I'm getting continuity to TRIAC and all other points as pointed out on the schematic made for pinwiki. I've tested everything from the topside to underside of the board and connectivity is perfect

I pulled the fuse and tested it, it's good.

I tested the AC voltage between J121-6 and J121-11 and there is none.

I've tested U1 pins with a probe as suggested here from Pinwiki:

"Failed 74LS374. This is rare too but easy to test following this procedure. You can also test the outputs of the LS374 by probing pins 2, 5, 6, 16 and 19 with your logic probe. At full GI brightness, these pins should test as "high"."

My probe showed all these pins on U1 to be low, not high, so what can I take from that? Is U1 dead? (I hope not).

I also tried this below and my probe was pulsing showing a signal was getting through to pin 11 of U1:

"U1 is "clocked" by the ASIC via the /TRIAC signal. If you have AC power present at J115, and no GI at all, it's possible that the /TRIAC signal is not getting through to U1. A logic probe applied to pin 11 of U1 will prove that the signal is getting through. "

I have new parts on hand for Q11 and Q12 but I don't want to change them without knowing they're dead... If U1 is dead I'll have to order one in. Question is how do I test Q12, Q11 to know if they’re faulty?

*edit: I just want to add that the next pin over, J121-5 has 6.8 volts AC.

To add to my last post... The lamps that are out are coin door, return lanes, under cannons, 2 pop bumpers, and a couple other under playfield lamps.

Any input is greatly appreciated.

This is a problem, either with the IC or in the way that it was measured.
Let's do that again. Make sure you are in GI test, and that ALL GI are at max brightness.
What your logic probe tells you at the noted pins should be identical and high.
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Can you confirm this measurement was from J121-11 to J121-5?

Agreed, if these all measured wrong then NO GI lights would be working. I'm assuming you have the game setting A1.25 "Allow Dim Illumination" set to NO.

Thanks very much for your wisdom to help me with this!

I just tried it with all gi on and set at full brightness. All pins 2,5,6,16,19 still read low.

The allow dimming is set to yes, and I can confirm that the ac 6.8v reading was from J121-11 to J121-5.
B57C50CE-190F-4D6E-AA5D-E81D99A6334D (resized).jpeg

...and by "probe", you do mean a logic probe, right?
Does your logic probe EVER show a high signal? You can probe the 5VDC test point to gain some confidence that your probe is working. Or just touch the probe to your finger. It should make a static-like sound.
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Yes thanks, I tested other points to see if it went high, even tried all other settings on logic probe. It will go high and is working.

I still haven’t figured this out if anyone has anything they’d like to add. It’s definitely not the end of the world having a few lights out, it’s just nice when you can say it’s all fixed!

Check the incoming voltages at connector J115 on the driver board. If one or more are missing and connector looks ok, check the big connector coming off the transformer that leads to the J115 connector. Usually all yellows wires on the transformer side. Look for burnt connectors on that connector.

Ok thanks, just checked it out. I’m not sure if I’m measuring right, but all of J115 should read 6.8vac right? I measured with my black lead on ground, and red lead on pins. 5 out of 11 pins read 6.8vac, and pin 12 read 8.7vac. The rest read 0vac.

I checked the connector by the transformer, and it’s not burnt at all. I disconnected it and plugged it back in and it fits nice n tight.

Am I checking ac voltage wrong?

This AC measurement was done correctly; any measured to ground would be incorrect for checking transformer voltages.

Thanks. Stupid question but where should my black lead go when checking 6.8vac at J115? Put it on J121-11?

On J115, pin 1 is the ground reference. It is connected to 1/2 of those signals back at the transformer.

On J115, pin 1 is the ground reference. It is connected to 1/2 of those signals back at the transformer. See image. In general, the correct way to measure AC voltage is between AC in and AC out. In this specific case, since half of that connector is connected to ground, the way you measured J115 is OK and the results you obtained are correct.
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Chris Hibler - CARGPB #31
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http://www.PinWiki.com - The Place to go for Pinball Repair Info

WPCGIConnections (resized).png

for AC measurements it doesn't matter.

I agree 100%...until it doesn't.

So my voltages coming in from J115 are good?

J121-6 still has no voltage so what could be the problem? Why am I getting low readings on logic probe for U1?

Let me make a video for you...tomorrow.
--
Chris Hibler - CARGPB #31
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J121-6 should have very little if any voltage normally when the string is lit. What you are looking for is 7vac at J121-7,8,9,10,11. These are the power feeds for the 5 gi strings. If those are all good, then you are looking for low volts on J121-1,2,3,5,6. These are your triac controlled ground circuits to turn on the 5 strings. The lower the volts at J121-1,2,3,5,6 the brighter the bulbs will be lit assuming voltage is correct at the power pins.
You read all these with your meter negative hooked to ground point anywhere in the game.

Thanks for the info! I just tested all pins with connector J121 hooked up and in test mode with all lights on brightest setting. Pin 1 was the lowest at 1vac, and then up to pin 5 were all around 1.6vac.

J121-6 wasn’t low though like you said it should be, it was 6.9vac, like the rest up to pin 11. Hopefully that’s a useful clue?

The pins for J121 were replaced before I got the machine but it looks well done, and I metered all connections from front to back of board and it all seems sound. All connections to triacs and fuse etc are good.

When you are seeing 6.9 volts on J121-6, where are you putting your ground lead? Earlier you said...

Is this still the case? Is anything connected to connector J119? Either way, test pins one and three (one lead on each pin) on J119 and see what you have there.

image (resized).png

If J121-6 is not driven low and currently measuring 6.8vac that means the triac for that string is not turned on, so the whole string is not lit at all. So your problem is in the triac or drive signals to the triac. Gets complicated from here. Only advice I can offer is compare readings on the good triac strings to the bad one using a logic probe and multimeter and hope something jumps out as vastly different between the two to narrow it down some.

Thanks for your replies.

I had my dmm black lead on ground screw.

Yes there’s a connector on J119. I get 0vac when I measure across the 2 pins of J119, but when I measure from ground screw to the pins of J119 I get 6.8vac on both. I did this with game in test mode, all illumination on high. Also the connector was still connected and I was measuring from the back of the connector.

Thanks, I’ll try probing around a bit.

I'm not sure that statement is correct.

You seem very technically competent, perhaps this information will point you in the correct direction:

When point "A" toggles low, then points "B" and "C" are high. This turns On the triac and the desired
General Illumination string lights.

pasted_image (resized).png
pasted_image (resized).png

Thanks!

This is how it’s working, as shown in the diagram you provided. Pin6 of U1 is low, and the triac and predrive transistors are reading high. I tested it with illumination on high in test mode.

To recap a bit, I have checked continuity from U1 through to lamp sockets and it all checks out.
C04EBA9A-5CDD-4AA8-AFA9-C22EA847951D (resized).jpeg

Thanks for the very helpful information. I logic probed all the other triacs and their predrive transistors in lamp test mode. They all had high predrivers and low triacs. My Q11 pre and Q12 triac were both high. I’m going to replace Q12 and see what happens since I have it on hand.

Good call, I have high confidence this will fix it; if it doesn't please look at this thread which is shockingly similar to yours.
https://pinside.com/pinball/forum/topic/t2-no-left-side-gi

If nothing else, I now have a fairly detailed drawing of the WPC GI schematic

WPC - General Illumination -Wire Color.png

I changed out Q12 but it’s still staying high on logic probe. I guess I should change Q11 predrive transistor? Ugh. It’s reading high like the other predrivers though so I’m not thinking that’s it.

I did go over that other thread you listed and went through all the notes but in the end his solution is different than mine. I checked continuity from the back of the connector J115-12 up to Q12 and its good.

Edit: I took the board out and tested Q11 with dmm and it reads the same as all the other transistors, so I’m pretty sure it’s not the problem, but do I just replace it anyhow? The resistors are both reading what they should be too. Gotta keep digging, but I’m at a complete loss here. Thanks again for all the input.

Edit2: I changed out Q11, no love.

You can always disconnect J119, J120, and J121 and put a single lamp across J119 pins 1 and 3 and see if it lights

I just tried that and it didn’t light a bulb holding it across the pins. I tried it both directions but I’m sure that doesn’t matter.

Not that this is new information, but you know that you either:

1) don't not have transformer power making it to J119-1, we measured it earlier, but just to make sure nothing has changed, connect one side of the lamp to J119-1, and the other to ground...it should light.

or

2) Don't have your transformer return path from J119-3 through Q12, through J115-12, to your transformer via lighting Molex connector pin 3.

I knew it wasn’t going to be the triac. Those never fail.

Use this diagram, with the board out of the game, to ensure continuity.

https://www.pinwiki.com/wiki/images/f/f9/GIBuzzPurple.jpg

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Chris Hibler - CARGPB #31
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http://www.PinWiki.com/ - The new place for pinball repair info

VioletGI (resized).png

Corrected...

Failed 74LS374. This is rare too but easy to test following this procedure. You can also test the outputs of the LS374 by probing pins 2, 5, 6, 16 and 19 with your logic probe. At full GI brightness, these pins should test as "low".

Additionally, pin 1 should test low. Pin 11 should test high pulsing.

With GI turned to brightness 1, the above referenced pins all pulse high.

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Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
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For some reason that diagram looks exactly like the schematic diagram to me.

ZAZA needs to make a .gif out of that that shows the high/low activation with a light bulb that turns on