Here is the latest, greatest lowdown showdown.
This set is almost as old as I am (I was still in diapers when this set was built).
Remember when I said the '31' in the model number did not sound right?
Well, it is. I found an obscure reference to it in my files.
The 31 denotes that this was a special-order set, and is Pennsylvania approved. There are several parts on this set that are not found on the standard JC's, and several parts that are different than standard.
These 2 relays are only found on the PA - approved sets. My parts books do show them, and they both show as still available.
However, I do not have access to special order schematics. None of the standard schematics show these relays.
I do have a good friend who may, though. But we will need to figure out which schematic it is.
Somewhere on the set - either on the data plate, or on a sticker inside the control box cover, it should list the schematic number. It may say diagram, schematic, or drawing.
Can you find this number?
Of the 2 relays, one is a start disconnect relay, and the other is a field build up relay.
Due to the fact that most of your wires go to meters or controls, I would suspect the one you are missing is the field build up relay.
The voltage regulator in your set is a large PC board. Is this the 'panel' you are seeing?