Hello, I am sorry I did not see your messages sooner. Yes, the F125 is a good frequency source for this equipment. One side of the bulb attaches to the ground connector on one side of the box. The other side of the bulb can plug into the connector marked P which provides a spark gap. Or the connector marked V does not have a spark. The red and black connectors are for a meter to read the frequency when the internal frequency generator is used. Only the spark gaps may need to be changed. The phanotron bulb does not need to be changed unless it is dropped and broken.
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