WPC driver board causing opto switch problem watch video

I have a problem with the driver board in my getaway. This problem is absolutely in the driver board cause when I replace the driver board the problem goes away.
Opto 1 which is the first opto for the supercharger doesn't work at all and is "stuck open". If you go into test mode and activate any of the pops or slings you will get a momentary closure of opto 1. If you disconnect j102 which is the AC in for coil and flash lamp power the opto come back to life and works correctly. Then if you activate pops and slings it doesn't cause a momentary closure of that opto (but the coil power is deactivated too). Also, while in test mode if you have coil power plugged in and disconnect the ribbon cable between the driver and CPU board the opto 1 works correctly and the pops and slings do not activate opto 1 either. I need some help in trying to figure this out. I'm guessing it's one of the chips in the driver board but don't know which one to start with.
Here's the video.

#2 7 years ago

ROB

Borygard

U8 is bad on the driver board.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#3 7 years ago

ERK

ekthoren

I'll change it and post back tonite. Thank you

#4 7 years ago

SLM

Slim64

Pinside member

9y 61,550 2,034

Quoted from Borygard:
U8 is bad on the driver board.
--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

Not questioning your diagnosis result, I'm curious how you came to that conclusion?

#5 7 years ago

ROB

Borygard

He's isolated the issue to the driver board. The only switch matrix interaction on the driver board is through U7 and U8.

U7 is switch matrix Row 2. U8 is switch matrix Row 1. The opto, and a sling and pop-bumper, are on Row 1.

The circuity to and around U8 could be an issue, or a data line problem on the driver, but with the additional info of coil power needing to be present for the problem to occur says to me, it's an internal issue with one of the 4N25s.

These chips input both low voltage from the switch matrix and high voltage from the coil power. An internal IC issue is really the only logical conclusion. Unless other game functions are affected, indicating a data line issue, but there's no evidence of that from what's been posted.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#6 7 years ago

SLM

Slim64

Pinside member

9y 61,550 2,034

Quoted from Borygard:
He's isolated the issue to the driver board. The only switch matrix interaction on the driver board is through U7 and U8.
U7 is switch matrix Row 2. U8 is switch matrix Row 1. The opto, and a sling and pop-bumper, are on Row 1.
The circuity to and around U8 could be an issue, or a data line problem on the driver, but with the additional info of coil power needing to be present for the problem to occur says to me, it's an internal issue with one of the 4N25s.
These chips input both low voltage from the switch matrix and high voltage from the coil power. An internal IC issue is really the only logical conclusion. Unless other game functions are affected, indicating a data line issue, but there's no evidence of that from what's been posted.
--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

Thank you!!

#7 7 years ago

ERK

ekthoren

Ok. I Changed out U8 problem still exists with no change. Any thing else to try (u7 even though it's row 2). Also in test mode the flippers do not activate opto 1 like the pops and slings do.

#8 7 years ago

ROB

Borygard

Could be. Williams' documentation is notoriously bad. I've not heard of Row 1 and Row 2 traces being swapped on the board, but that's definitely something I could see Williams doing.

There's really nothing else related on that board. Are there any lamps lighting when they shouldn't, or coils firing other coils?

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#9 7 years ago

ERK

ekthoren

Everything else is fully working as far as I can tell. I will change out u7 too. I was looking at u6 but not sure what sw j1 and sw j2 referred too on the schematics.

#10 7 years ago

BTF

PinballManiac40

Pinside+ Frequent

14y 234K 17,622 104

Can you tell if C2 (100uf 25v) capacitor leaked underneath? I seen random switch errors on TAF due to this. Even started eating up the traces under it.

#11 7 years ago

ERK

ekthoren

Ok. I've changed u8, u7 and u6. No change to problem. I will look at c2.

#12 7 years ago

ROB

Borygard

Remove the ribbon cable from the driver board and see what things do. You won't have any solenoids or controlled lamps, but it will be interesting how your switches behave.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#13 7 years ago

ERK

ekthoren

In my original write up I did remove the ribbon cable. It "fixes" the problem also even with the j102 connector attached. I replaced c2 with no change.

#14 7 years ago

ERK

ekthoren

I'm going to take a break in this until tomorrow.

#15 7 years ago

ROB

Borygard

So further troubleshooting gets risky. Not irreversible risky, but breaking header pins or destroying ribbon cables risky.

Remove pins 3 and 5, one at a time from the ribbon cable going from the driver board to the CPU. Either by bending them out of the way (very easy to break, be prepared to replace). By desoldering the pin and pulling it out. Or by cutting the ribbon cable at the proper spot.

You're trying to determine which pin is responsible for the issue.

Alternately, you can visually, and with a continuity meter, follow each pin through the driver board to the 4N25. You'll be looking for anything amiss, a solder splash, a shorted trace, a piece of debris. You'll end up doing this anyway after determining which pin is responsible for the issue, but you'll know exactly which to follow if you do the above first.

--
Rob Anthony
Pinball Classics
http://www.LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#16 7 years ago

ERK

ekthoren

Ok---we have progress. Pulled pin 3 of j113 (ribbon cable driver board) and their was no change. Put pin 3 back in and pulled pin 5. The problem went away! Pin 5 leads back to leg 5 on U8 (not u7 like the schematics say). I've spent a little time and I can't find a short with anything else.
I put pin 5 back in (problem came back) then I pulled U8 since it's socketed and the problem remains even without U8 installed. I'll spend some more time after lunch tracking this down. Also pin 5 on header is not shorted to any other pins on header.

#17 7 years ago

ZAZ

zaza

Pinside+ Frequent

10y 92,650 3,268

I checked if Column1 and Row1 traces were next to each other under C30 and that maybe a leaking capacitor could cause this behavior.
But the 2 traces are separated by Row2 so it's not very likely the capacitor.

column1 = green line
row 2 =red
row 1 =brown

column1 row1+2.jpg

#18 7 years ago

ROB

Borygard

Technically, since HS2 uses Fliptronics, you could leave pin five removed from the header. Of course that doesn't actually fix the issue, which I'm not a fan of, but it would solve your problem.

--
Rob Anthony
Pinball Classics
http://www.LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#19 7 years ago

ERK

ekthoren

I'm not a fan of fixing the symptom only either. I will keep going....for now

#20 7 years ago

ERK

ekthoren

Just to doubly confirm it's on the driver board since pin 5 of ribbon cable hearer is only connected too leg 5 of U8 I put driver board in wh2o and it exhibited the same problem. Row 1 opto switch wouldn't work but when you activated pops and slings in test mode it momentarily activated. Back on bench.

#21 7 years ago

ERK

ekthoren

Decided to take on the power side and work forward. So if I pull f102 with everything else connected the problem goes away. Since the only thing between f102 and U8 is r211 I'm going to pull it and replace. R211 tested spot on under no load at 3.3k but I'll replace anyway.

#22 7 years ago

ZAZ

zaza

Pinside+ Frequent

10y 92,650 3,268

The traces of Row1 and the resistor R211that carries +70V from F102 are very close to each other underneath U8.
Maybe due to corrosion or metal dust there is an electrical influence between those 2 traces ?!
U8 70+R1.jpg

#23 7 years ago

ERK

ekthoren

Fixed!!! Spot on Zaza. Rob you were correct from the beginning with U8 also but I missed the real issue. It was not the resistor it was a short. I looked at U8 again and measured resistance for any shorts. Their was about 100 ohms resistance between leg 5 and leg 1 of U8. I had already socketed the chip and when I pulled the socket off again I couldn't see anything touching but the resistance was their instead of being open. So I desoldered it a couple seconds longer than I should have and the pad came off of leg 5. That removed the short. So I put a jumper wire on leg 5 of U8 to pin 5 of ribbon cable header. Now the board is fully functional and has no issues. Thank you everyone for your input.

#24 7 years ago

DLS

bigd1979

Pinside member

Hagerstown, MD

10y 137K 14,191 8 78

Very awesome and great community help... reason i love this place

#25 7 years ago

ZAZ

zaza

Pinside+ Frequent

10y 92,650 3,268

Wow, I'm very glad you took the effort to find the cause and not leave the pin J113-5 away to get rid of the effects.
Last year there was a similar issue here on pinside and couldn't pinpoint the cause of it.
Good to know that this area on the powerdriverboard can be the cause of this behavior in the switch matrix.

#26 7 years ago

ERK

ekthoren