So just keep ‘em running as best you can during the MOD right?
Only other thing I can think is looking to see if the Dispatcher uses the same Power Supply as car 1 and substitute it with that, or picking up the 5V from the next nearest car and jump it over. The Dispatcher I think has a clock that scans left to right at the bottom left corner of the red plastic overlay panel. When the unit fails, is this clock scanning? Also, in the first photo, the image was blurry. I was unable to see the status of the other cars at the lower part of the red panel.
Available documentation for troubleshooting, fault diagnosis etc for those units will be tough to resource. Of course to do any of that you need the PCD designed for the MP1200 or 1210 as well. Early 80’s is a good guess for install year for that type of control.
One other thing; when the Dispatcher freezes up, and all cars are on auto and are “stuck” (and not running, doors closed) open the main line power of each car one at a time to see if one of the running cars is somehow the trouble.
