MCOR-4 Disassembly

[Tom47]

I decided to open this defective MCOR-4 to see if it could be user repairable.

I found it fairly easy to open and disassemble. Removing the circuit board to get to the switch and contact wipers requires breaking off two of the four mounting pins.

The control can be reassembled without the pins by melting some plastic from the case to hold the circuit board with a soldering gun.

The switch would be user replaceable if one can be found. My original problem was occasional resistance readings of 30 to 50 ohms when the switch closed, instead of "0".

Strangely, when I checked the switch after opening it, it worked perfectly each time. After reassembly, it continues to work. I don't know why as I didn't identify any problems with the mechanical operation.

I'll keep it as a backup spare if and when the replacement acts up.

By the way, my original concern about overtravel causing erratic switch operation is not possible. The cam point that closes the switch cannot be over travelled.