OHHH Sensors

[hobbes49]

Neither of my OH! Sensors are working. This is on a blue 83 chexx. If I place the puck over either sensor I hear clicking so I don't think it's the reed switches. I have tried reconnecting all connectors involved. Any idea what chip(s) on the main board are responsible for this?

Possibly related, I get an OH! out of the audio after the puck is ejected. That's the only time. Thanks in advance!

[lukerailey68]

The reed switches are mechanical so they are probably the source of the clicking noise. The chips on the main board responsible for the OH sensors are MT1 or MT5 for either side. You can see them in the schematic I have attached.

[hobbes49]

Thanks Luke, that is very helpful.