(Topic ID: 246789)

(SOLVED)WPC Trough Opto Issue


By shaub

9 days ago



Topic Stats

  • 26 posts
  • 7 Pinsiders participating
  • Latest reply 5 days ago by shaub
  • Topic is favorited by 2 Pinsiders

You

Linked Games

Topic Gallery

There have been 2 images uploaded to this topic. (View topic image gallery).

J3 7-opto.png
LM339 (resized).png

#1 9 days ago

I have a Flintstones machine and the Trough Opto 1 always registers as "open" meaning it thinks there's a ball in that spot. I tried to narrow down where the problem was but I was unable to do so. Could anyone direct me to the proper path to test?

#2 9 days ago
Quoted from shaub:

Could anyone direct me to the proper path to test?

http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Opto_Switches

This may help. Though that opto spot might be bad, receiver or transceiver.

LTG : )

#3 9 days ago

Transmitter opto is best to test with a digital camera or most cell phone cameras. If it is not lit, it would be like a ball blocking the light, even if a ball is not there.

#4 7 days ago

I replaced both transmitter and receiver and no change. Im going to check out the opto board next.

#5 7 days ago

check you connectors on the trough board, at best replace the Molex connector, there problematic.
I find this is always where I've run it to this problem, if its not a optic sensor.

#6 7 days ago

checked connectors, they're all fine and match the manual. Jumped switch columns with rows, all trigger properly.

#7 7 days ago

On the 7-opto board, changed LM339 at u1, checked the resistors, changed the diode. The game still thinks there is always a ball in the spot.

#8 7 days ago

Please post a picture of your MPU board.

#9 7 days ago

If you have checked everything else, then it is time to follow the wires an make sure there is continuity between the backbox and the trough.

#10 7 days ago
Quoted from donjagra:

If you have checked everything else, then it is time to follow the wires an make sure there is continuity between the backbox and the trough

Just checked for continuity on both the column and row wiring from cpu to opto board... all good.

I think im gonna need to actually test the lm339 on the opto board, just need to figure out how to do that first.

#11 7 days ago

Check volts on transmitter and compare with other working ones, and same for the receiver. Volts should have a definate switch when ball is sensed, then procede to opto board to make sure switching is there as well, then check column and row wires out of the opto board for connection to other switches in the same row and column.
Sounds like you already checked the row and columns, but did you check for voltage swing at the wiring into the opto board?

#12 6 days ago

The voltage at J1 connector on the trough opto receiver board are around 2V when the transmitter board is plugged in, 13.8V when the transmitter board is unplugged. Voltage is effectively 0V at the opto itself when the transmitter board is plugged in, 12.2V when the transmitter board is unplugged.
Voltage at the connector and the optos themselves on the transmitter board is around 1.2V.
That all appears to be proper, correct?

The problem must be on the 7-opto board itself, no?

#13 6 days ago

How do I go about testing the LM339?
LM339 (resized).png

Ok, I've decided my next course of action is to check the voltage on the opto board at J3 pin 6 and at the switch matrix 209 pin 2 and to compare them to the other switches with the transmitter board plugged in, and then unplugged to determine if the LM339 output is working properly.

#14 6 days ago

Ok, well it looks like this is just an issue that I'm going to have to live with. I don't really feel like investing any more time into shot in the dark attempts at finding the problem.

Flintstones: 1, Shaub: 0

Thanks everyone for your suggestions.

#15 6 days ago
Quoted from PinballManiac40:

Please post a picture of your MPU board.

I am still waiting to see a picture.

#16 5 days ago

what are you looking for on the mpu?

#17 5 days ago

Battery damage

#18 5 days ago

the switch matrix tested fine.

#19 5 days ago

And yet you are trying to fix a trough opto one failure, which is part of the switch matrix.

I should have added that the picture include the writing attached at the bottom of the board, so there is no red to remove it from the game.

I have seen a lot of odd things with battery damaged boards.

#20 5 days ago

Well yeah, but I've isolated the CPU switch matrix connectors and tested them independently, so wouldn't that suggest that the switch matrix on the cpu itself isn't the problem?

#21 5 days ago

If you decide to try again, remove the opto board from the game and take a picture of the transmitters while the game is turned on. Be careful because I have fried a board doing this. I would be very interested to see the photo.

#22 5 days ago

And if you pull J3 from the 7-opto-board. Have the machine in switchtest T.1 and put a diode in the IDC like this,... does that trigger switch #31 in the test ?

J3 7-opto.png

#23 5 days ago

Success!

After following the jumper test mentioned at "6.24.5.3 7 Opto Board Testing" in the pinwiki for Williams WPC (http://www.pinwiki.com/wiki/index.php?title=Williams_WPC), I was able to determine for certain that the 7-opto board was my problem.

After further investigation: removing the socket at U1 and testing continuity between all the traces, it turned out to be a broken trace between pins 7 and 9 on the U1 LM339, which, based on my limited understanding of most things, means that the LM339 was comparing the voltage input at pin 6 to absolutely nothing and so the output would always at pin1 would always be the same.

Thanks everyone for the help and guidance, what a great community!

#24 5 days ago
Quoted from zaza:

And if you pull J3 from the 7-opto-board. Have the machine in switchtest T.1 and put a diode in the IDC like this,... does that trigger switch #31 in the test ?

Dammit Zaza, where were you earlier? Haha. That is what I ended up doing to confirm that the 7-opto board was the problem.

#25 5 days ago

sorry, was busy doing nothing.

That test is always handy to find out in what direction to search.
Glad you got it repaired now

#26 5 days ago

Yeah, I learned a lot about opto issues that I'm sure I'll use in the future.

Promoted items from the Pinside Marketplace
$ 159.99
Lighting - Other
Lighted Pinball Mods
$ 20.00
Playfield - Decals
Pinball Haus
$ 6.95
From: $ 16.95
$ 9.95
From: $ 9.99
Eproms
Matt's Basement Arcade
$ 50.00
3,000 (OBO)
Machine - For Sale
Lodi, WI
$ 194.99
Lighting - Led
PinballBulbs

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside