You should be able to visually inspect the traces and figure out if those two are supposed to be connected. My guess is that they are.

Dr. Who is such a pain to get apart to get those that I recommend replacing them all while you are in there. If it continues to fail you might want to check the wiring. They can get internal breaks and work in some positions but not others.

That’s correct, all transmitters and receivers on each board share a ground wire, the other traces are individual to each diode

Try electrical tape on the ends to prevent any external light exposure, blacking out the area and cleaning the optos usually fixes a lot of problems.

Or make a new shroud from the template

Even with the shroud, you will still need some sort of tape to seal the edges.

Not sure why? The original design still works perfectly fine

Mine didn't until I taped the edges, and neither did the one I am rebuilding for a friend.

No kidding? That is unusual - neither of the DW I’ve owned required that. I wonder if the optos had been replaced with more sensitive ones?

I have owned 2 DR Who's and I had to re-solder all the Opto's legs to fix them. All the banging they get from the balls whacking them causes them to come loose from the solder that holds them in. Also when I have had to replace opto's on any pin 99% of the time it was the transmitters that were defective.

I usually order the new bds from great lakes modular . Saves lots of headaches

Sorry to say, but just order the ones from GLM. You will never want to disassemble the mini-PF again. It’s worth the $$

If the receivers are interfering try reversing the 2 boards. Its possible they are flip flopped.

That is not normal

The way that bracket is bent is usually a result of someone installing washers to offset the taller optos

Just get a Dremel and grind the black optos down a bit. They will still work fine and you’ll have the clearance you need. Avoid the washers!

This device will square your bracket giving the buttons enough clearance to operate smoothly. Plus, it will eliminate light bleed. If you don't own a 3D printer, you can order a print through the site. That's what I did. Treatstock was printer I selected. Great quality and it cost me less than $10, including delivery.

https://www.thingiverse.com/thing:2387162

By the way, I'm in exactly the same boat as you. I ordered replacement optos from Marco (Gulf Pinball is the manufacturer). The output from the transmitters is so weak that I only get a response when they are literally touching the receivers. I'm still trying to work out if the issue is with the board or my terrible soldering skills. Have you been able to make any progress on your setup?

optocover (resized).jpg

The smallest amount of light getting in will cause problems for optos. I agree totally with dsuperbee and speak from experience regarding ensuring you tape the edges of the shroud.

I tried the opto kit too and found they did not work. Figured there was some compatibility issue. The real reason for the opto issues are due to the plastic holder being warped. This looks like it remedies the issue. Wondering if it was E-Z to remove the gray buttons from the old plastic to the new? Also anyone know where to find or print new gray plastic buttons?

https://www.shapeways.com/product/Q6BMQBFSZ/doctor-who-pinball-mushroom-target-button-1-off?optionId=65150365&li=marketplace

This device will square your bracket giving the buttons enough clearance to operate smoothly. Plus, it will eliminate light bleed. If you don't own a 3D printer, you can order a print through the site. That's what I did. Treatstock was printer I selected. Great quality and it cost me less than $10, including delivery.
https://www.thingiverse.com/thing:2387162

Had the device 3D printed by my neighbor. He just copied the file and printed it. The part slides into the original bracket--E-Z. The only issue I have is with the part installed, now the opto boards pick up more space which causes the large metal housing that sits below the opto targets to not screw in perfectly. The 4 screws are not snug, but still hold the large metal housing in place. This is the metal housing that moves up after you hit the targets. Opto issues---Fixed.

Just some e-clips holding them in place. You can remove them with needle-nose pliers. The biggest concern is ensuring you don't lose them. They're small and can fly pretty far!

My optos are working now, as well. I got in contact with Gulf Pinball and he sent me a new set that work perfectly. He said he got a batch of dud LEDs. So, for anyone else having problems with their Gulf Pinball optos, PM me for his contact info.