[TowerTalk] Rookie Question

[Bill Coleman]

On Oct 11, 2005, at 9:52 PM, Al Zelna wrote:

> The long and short of it is the rotor does not turn.  I can't even  
> hear the
> brake click!

If the brake solenoid doesn't click, then you have a problem. If  
someone is standing at the base of the tower, the solenoid should  
thunk loud enough to hear.

If you go out on the BAMA site, you can find a manual for the Ham-M.  
This manual has a bunch of useful information, including some  
ohmmeter tests you can use to check the cable and rotator.

First thing to check is if the controller is putting out the 30vac  
needed to pull in the solenoid.

>   The soldered ring-terminals are connected properly to the
> rotor and controller.  Although I have yet to check continuity. and I
> realize this could certainly be the problem, I wonder about the motor
> starter cap in the controller being the culprit.

Very likely. The Ham-M was produced until the end of 1973. I have a  
series 5 from 1975 that I bought used for $50. This is really a Ham- 
II, but it came with the Ham-M controller.

Note that all of these devices are more than 30 years old. It isn't  
unusual for the motor cap to be bad. Mine was. Fixing it was easy. I  
removed the cap from the controller. Instead, I have the replacement  
cap mounted in a box near the rotator on the tower. This box  
terminates my rotator control line run, which then switches to a  
couple of 4-terminal trailer hitch connectors.

When I was testing the rotator on the ground, it would just barely  
turn with no load. Weak turning is a good symptom.

Another problem with the Ham-M controller is the rotary switch  
contacts tend to burn off. (I have a spare controller like this that  
I plan to re-build into a Ham-II style control box)

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901