Collectors on F3

Here is a diagram for reference:

Another thing to consider is if the collector is mounted with the sliding shoe in the wrong position it will short out when on the track. The slide shoe should be on the Fireman's side of the engine.

Thank you for the information.  I discovered that the shoe was the culprit.  I had never considered it before in my investigation.  Thank you all.

Glad to hear you fixed it.

Yes, I was thinking all along it was the wrong screws but it turns out that the shoe rivet was touching and shorting out.  I am working on another F3 that I built and something is shorting out on this as well but its not the shoe this time.  Turns out I have a bad E unit.  Probably the fingers inside unit are not touching the barrel correctly.  Someone rebuilt this and put wrong colored wires in it.  I am going to rebuild it with everything the way it should be.  I hope I have better luck with it.