[TowerTalk] Need help with Tailtwister

[kq2m at kq2m.com]

Hi Joe,

As it turns out it was both the control box and the rotator.  After 
checking the voltage readings between pins 3-7, 1-2. 1-5 and 1-6 (all 
zero) and comparing against 13.5 v between 3-7 on a good control 
box/good rotator, I checked the internal fuse which was blown.  After I 
replaced it, the rotator STOPPED rotating with that control box! and the 
directional indication and calibrate were giving me wacky readings. I 
then replaced the flaky control box with another known working control 
box and got different wacky readings but the rotator rotates again 
although I can't tell how far it has rotated by looking at the control 
box. I have to look at the antenna.

The resistance between 3 - 7 is not ~ 500 ohms like in the good control 
box/good rotator; rather it counts up from 100 ohms and the when I 
retest it and then it counts down from 900 ohms.  This has happened 
before and I believe that the rotator is screwing up the control boxes 
over time and then causing them to malfunction.

I need to replace the rotator and, just to be safe, replace the rotator 
cable as well.  That should solve the problems I am having but it will 
have to wait until the Spring.

Tnx & 73!

Bob, KQ2M


On 2021-11-19 16:33, Joe Subich, W4TV wrote:
>> I seem to remember something about an internal fuse in the control
>> box - could that be a source of the problem?
> The fuse on the meter supply is shown on the schematic in your T2X
> manual.
> 
>> with the needle pegged to the left end of the scale.
> 
> Is the meter pegged with the control box turned off?  Can you reset
> the needle to the left "S" indication with the adjustment screw on
> the face of the meter (with the control box off and disconnected)?
> 
> A meter deflection to the left of zero *might* indicate a shorted
> CR1 on the meter supply board (I have not tested that hypothesis).
> 
>> but the direction indication got erratic very briefly and
>> then stopped indicating.
> 
> I would look to see if the cabling to the motor unit has been
> damaged or if the rotator itself has come in contact with any
> power cables.  Erratic behavior indicates a problem with the
> pot or wires 3 & 7.  A meter deflection to the left of zero
> indicates that terminal 3 (+ side of the meter) is *negative*
> with respect to terminal 1 (wiper/ground).
> 
> Disconnect terminals 3 & 7 (or unplug the Cinch-Jones plug)
> and measure the voltage between 3 & 7 ... it should be around
> 13V DC (regulated by VR1).
> 
> 73,
> 
>    ... Joe, W4TV
> 
> 
> On 2021-11-19 4:26 PM, kq2m at kq2m.com wrote:
>> 
>> Hi,
>> 
>> I have a sidemounted T2X @ 37' which turns a 5L 105CA.  The rotator is 
>> turning fine but the direction indication got erratic very briefly and 
>> then stopped indicating - with the needle pegged to the left end of 
>> the scale.
>> 
>> I had this problem once before and replaced one control box with 
>> another and there was no problem for a few years until now.
>> 
>> Does anyone know what is causing this?  I seem to remember something 
>> about an internal fuse in the control box - could that be a source of 
>> the problem?  I also realize that it could be a potentiometer with 
>> dirty contacts in the rotator but I don't think that is it since the 
>> indicator was only briefly erratic before it stopped indicating.
>> 
>> I would appreciate any thoughts and potential solutions.
>> 
>> Tnx & 73
>> 
>> Bob, KQ2M