(Topic ID: 293297)

WPC95 16 opto board issues

By Nixpaints

6 months ago


Topic Heartbeat

Topic Stats

  • 14 posts
  • 5 Pinsiders participating
  • Latest reply 6 months ago by DumbAss
  • No one calls this topic a favorite

You

Linked Games

Topic Gallery

View topic image gallery

boards_065 (resized).jpg
boards_028 (resized).jpg
boards_030 (resized).jpg
16 OPTO (resized).png
pasted_image (resized).png
pasted_image (resized).png
16 opto (resized).png

#1 6 months ago

Hi all! Looking for some direction on my faulty NGG opto board. It all started with ground short row 1. I checked all switches in the row, jumpered at the board (no battery corrosion before someone asks) and isolated the problem to the opto board. No luck with switch tests for the lm339s per pinwiki as T1 constantly cycles closures across all rows and switches. I register 12v in at J5 but all outs on J2 & J4 are around 1v. Any pointers from the most resourceful pin peeps on the planet?
Many thanks

#2 6 months ago

Replace the LM339 and the 100 uf Cap

#3 6 months ago

Which one tho? The board has 5 lm339s. I’d prefer to start with the one(s) that run row 1 as that was the first fault

#5 6 months ago

Get out your schematic and figure out which pin on the 16 opto board is your row 1.

16 opto (resized).png
#6 6 months ago
Quoted from WH20_Buzz:

Replace the LM339 and the 100 uf Cap

I would defiantly start with the capacitor, but one thing you will have to pay close attention to is if there is the integrity of the thru holes the capacitor solders into. The dielectric in a capacitor is corrosive and will destroy these contacts just as a leaking battery does but at a much slower rate. This corrosion can break the connection of your 12V which is your reference for the LM339s that control the column reference for the other four on the board.

Quoted from Nixpaints:

Which one tho? The board has 5 lm339s. I’d prefer to start with the one(s) that run row 1 as that was the first fault

Getting the correct one can be a little tricky as there is no single LM339 dedicated to row 1. I wouldn't replace any of the LM339s without doing proper checks first, most will require a logic probe, but a lot can be done without one.

Start by Checking for 12V at pin 3 of all LM339s as well as Pin 1 of J2 and J4, and also check the reference voltage going to both of the comparators used to develop the column reference voltages.
pasted_image (resized).png

Quoted from pins4u:

Get out your schematic and figure out which pin on the 16 opto board is your row 1.

pasted_image (resized).png

#7 6 months ago

Now that’s what I’m talking about! Thanks fellow pinsiders!!! Should be all I need. Side note, checking cap was my first step on the board and tested fine. Cheap and easy to replace tho so will do

1 week later
#8 6 months ago

Sent the board off for repair as I didn’t have time to replace the chips myself. No luck...opto board checks out just fine. Where do I go from here? Im obviously missed something.

Edit: still can’t get into switch edges as it scrolls across all switches in rapid succession of rows

#9 6 months ago

Update: owner of a local pinball pub let me plug the opto board into his junkyard. Confirmed that’s the problem. Apparently bench testing without having a game to test in is not %100 accurate

#10 6 months ago

https://www.pinballlife.com/16-opto-replacement-board.html?Category_Code=

$99.95 and a bonus is the ICs are socketed to make future faultfinding easier.

16 OPTO (resized).png

#11 6 months ago

I think DumbAss can provide a very high quality board at a lower price.

#12 6 months ago
Quoted from Nixpaints:

Confirmed that’s the problem. Apparently bench testing without having a game to test in is not %100 accurate

Depends how its bench checked, did they happened to send you a breakdown of the tests performed?

#13 6 months ago
Quoted from Pin_Guy:

I think DumbAss can provide a very high quality board at a lower price.

Isn't it FANTASTIC that we actually have several options these days. I can remember when, if you couldn't fix the board, that was IT! Your machine stayed broken until someone parted out a machine and you were lucky enough to actually get a used board.

These days we have several options for this board and most are superior to the originals. The Pinball Life one I referenced is under $100 - simply amazing!

#14 6 months ago
Quoted from Nixpaints:

Apparently bench testing without having a game to test in is not %100 accurate

Quoted from Pin_Guy:

Depends how its bench checked, did they happened to send you a breakdown of the tests performed?

I am glad that somebody else was thinking what I was thinking. Every opto board I have built and sent out passes on my bench and nobody has mentioned any problems when received. Testing equipment is important!

boards_030 (resized).jpg

Quoted from pins4u:

Isn't it FANTASTIC that we actually have several options these days.

Quoted from pins4u:

These days we have several options for this board and most are superior to the originals.

100% agree. Choice is good for the consumer. It also means that the consumer should do more research on what's available and weigh up the pros and cons of each solution. Of course, that's not required. Just like getting a second quote with a different contractor or a second opinion from another medical professional. It's 100% up to the buyer how much effort they want to put into their purchase.

Quoted from Pin_Guy:

I think DumbAss can provide a very high quality board at a lower price.

If the OP (or anybody else) is interested I have two versions of the board available. The original Williams circuit (with ICs in sockets) or a re-designed circuit with discrete transistors and LED indicators for the transmitter/receiver pair.

boards_028 (resized).jpg
boards_065 (resized).jpg

Please use PM if interested.

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