[stackj]

There is a 'simplified' electrical diagram for the electrical systems of S/N 337-0535 through 337-0755 on this web site. To get a copy of it, go to the home page and select 'Technical Data' from the menu on the left.

On the Technical Data page, scroll down until you see a link labeled 'Electrical System Schematic (PCX Format).

Select and print this diagram. I have compared this diagram to the one for S/N 337-0016 and the field circuit seems to be the same. Use the diagram to get a better understanding of the field circuit and what items can afffect both alternators.

Here is the field voltage path:

1. Main bus bar
2. Exits through 'GEN FIELD' circuit breaker (5 amp)
3. To Master Switch
4. To 'RUN/STBY' switch
5. To 'Over Voltage Relay'
6. To 'Regulator Select' Switch
7. To 'GEN On/Off' Switches - Problems up to the input of this switch will affect both alternators.
8. To Individual Alternator Field.

I have had problems with dirty switch contacts in these circuits which caused intermittent operation of my alternators. Your description of the problem tends to point to the field switch section of your master switch.

Good Luck