(Topic ID: 249685)

Question Opto receiver diode poles

By jimy_speedt

3 months ago

Topic Stats

  • 3 posts
  • 2 Pinsiders participating
  • Latest reply 3 months ago by jimy_speedt
  • No one calls this topic a favorite


Linked Games

Topic Gallery

One image has been uploaded to this topic. (View topic image gallery).

AA9F34C4-F7E8-4D8F-8D8E-146BB3B8D8D4 (resized).jpeg

#1 3 months ago


I need to replace a diode on the receiving board of a Junk Yard through. I have seen much diagrams relating to the transmitter diode, but could not find any spec for the receiver. There is a long and a short leg to the diode. How do I map them to the board holes ?

Any help is welcome

Thank you
AA9F34C4-F7E8-4D8F-8D8E-146BB3B8D8D4 (resized).jpeg

#2 3 months ago

Since you refer to "Diodes" then I then you would be referring to Infra-red emitting LEDs -- short lead is anode, long lead is cathode.
** Flat side of plastic base is oriented towards the cathode. **
See page 3-16 of the Junk Yard manual for orientation of the LEDs.
This manual can be found on ipdb.org

But if you are referring to the receiver board then those are phototransistors (not diodes).
For the receiver board's phototransistors -- short lead is the emitter, long lead is the collector.
** Flat side of plastic base is oriented towards the emitter. **
See page 3-17 of the manual for orientation of the phototransistors.

This assumes you are using QED123 (IR emitter LEDs) or equivalent and QSD124 (IR phototransistors) or equivalent.
Since you don't mention the part number of your new replacements, this is as close I can get.

#3 3 months ago

For the terminology, I am talking about the receiver led. Thanks for your input.

Promoted items from the Pinside Marketplace
From: $ 16.95
$ 40.00
Lighting - Other
Rock Custom Pinball

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