[TowerTalk] CDE HAM II Rotor . . . another question

[Bill Aycock]

Steve- the problem may be in calibration, not the resistor. My CDE Ham III 
has a simple procedure, and I think the type II is the same. A slightly 
shortened version is:
Turn the unit on and  turn the rotator to the most counterclockwise 
position. Use the screw in the center of the meter to move the needle to 
line up with the leftmost "S" limit.  Push in the "calibrate" knob. Rotate 
the knob to place the needle on the right hand "S" limit.  Push in the 
"Calibrate" knob.
This procedure can be repeated anytime to check the calibration. With the 
power off, the needle should aligne with the left "S".
That is what the manual says.
Bill




At 08:51 PM 5/27/2004 -0400, you wrote:

>Several of you were kind enough to help me a few weeks with a question 
>about a CDE HAM II rotor. Now I have another issue and thought I'd try my 
>luck again.
>
>I bought this CDE Ham II rotor in 1976, used it for about five years and 
>removed it from service and stored it.
>
>The problem I'm having is with the direction indication on the control 
>unit. If the rotor starts at full south and I turn it in the SENWS 
>direction, it seems to work ok. But if it's full south and I turn it in 
>the SWNES direction, the indicator meter on the control unit stops at 
>about 270 degrees even though the rotor is still turning. When the rotor 
>gets to about 360 degrees, the meter jumps to the correct indication and 
>works ok through the rest of the travel to south. So the indicator meter 
>works OK in one direction but not the other.
>
>I thought there was a problem with the potentiometer assembly and so 
>bought a new one from the Hy-Gain people at Dayton. I replaced it and 
>learned that the new potentiometer assembly exhibits essentially the same 
>behavior as the old one :(
>
>With the top casting removed the potentiometer assembly is readily 
>accessible and easily turned by hand. I see the same 270-to-360 jump when 
>turning it by hand.
>
>Where do I go from here? Two defective potentiometer assemblies? It seems 
>like pretty long odds that a potentiometer assembly from 1981 would 
>exhibit the same anomalous behavior as a new one I bought this month.
>
>Any advice out there?
>
>Thanks.
>
>Steve
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>
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>
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Bill Aycock - W4BSG
Woodville, Alabama