Ham IV Rotor Control Box Troubleshooting

Thread Starter

tracecom

Joined Apr 16, 2010
3,944
I have a Ham IV rotor that was on a tower that was struck by lightning several years ago. I am trying to repair it, and am starting on the control box, which is disconnected from the rotator. A schematic diagram is shown below.

There is no apparent damage to the control box except that both fuses were open. I removed them, and put in a new AGC 5 in the F2 position; it blew as soon as I turned on switch S1. If I am reading the schematic correctly, S3 (N.O.) prevents current flow through the power transformer, therefore I suppose the first problem to be in the regulator circuit inside the dashed lines. What is the logical progression of things to check? Thanks.
Ham IV Rotor Schematic.JPG
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
23,797
S1 powers the primary of the transformer marked meter, I would suspect any thing on the DC power circuit, try disconnecting the secondary first and test any diodes or rectifiers on the output side.
Max.
 

Thread Starter

tracecom

Joined Apr 16, 2010
3,944
OK, CR1 was open, and VR1 was shorted. I replaced them both, the bulb lights, the fuse blowing has stopped and I measure 13.48V across the zener. Progress!
 
Top