If the switches are open and then close (register) when you short the pins and then open when you remove the short then there's nothing wrong with the logic detection. It MUST be the opto pair.
I assume the other opto pairs controlled by the 7-opto board register correctly. This would be switch 57 (Bumper Lane Opto).
Quoted from Brewchap:But, I just replaced the pair as the 1st troubleshooting step that I did. I also double checked with the pictures that I took before removal of the wires and they are wired the correct way.
This assumes that the components are installed correctly.
- How about an image of the boards you bought?
- Or a link if the boards are stuck inside the bookcase.
Most board manufacturers don't provide the datasheet of the component they installed on the board.
- The transmitter (LED) is usually a standard part. The anode is the long lead and the cathode is the short lead. There is a flat edge on the dome that indicates the cathode.
- The receiver (phototransistor) does not have a standard. The long lead can be the collector or the emitter. It depends on the part manufacturer.
You can use a camera without an IR filter to verify the transmitters are working. Try the "selfie" camera on a phone. It should show something. To check the receiver, use a DMM and measure the DC voltage at the emitter. This should nominally be 12V if the transmitter is producing IR light that is falling on the phototransistor.