[TowerTalk] Diagnosing a stuck rotator

[Steve Harrison]

On 12/11/2023 8:19 PM, john at kk9a.com wrote:
>  From your post is sounds like your rotator is either stuck or does not have
> enough voltage to turn.......
.............
> It is a long run, broken at the tower base with easy to inspect connections.

If the connections are easy to inspect at the tower base, start there 
with your trusty DVM; you might have to borrow the XYL or your kid to 
manipulate the controller controls inside. If possible, measure the 
motor current with a clamp-on ammeter, whichever it uses, AC or DC. If 
you get it running while down below, you should be able to measure the 
voltage across the reed switch as it rotates and detect whether the reed 
switch is switching consistently and smoothly. If all seems hunky-dory 
down below, then you have no recourse but to go up the tower to the 
rotator and repeat your measurements, which will likely mean having to 
make some sort of extension cable by which to access the connector 
connections.

If you get it running again during this time. try shaking the cable and 
wriggling the connections at the base both going up the tower, as well 
as leading back to the shack, then again in the cable going up the 
tower. Also, try loosening and tightening all the connections at the 
tower base; perhaps one has corroded.

And perhaps it's as simple as someone, somewhar, just plain forgot to 
solder one of the motor connections in the connector... =8-/

SOMETHING, somewhar, is loose and/or intermittent. I would find it VERY 
hard to believe that just a DB36 would be enough to overload and stop an 
OR-2800, unless the mast is severely binding while going through the 
upper thrust bearing. And it's always possible, although unlikely, that 
the thrust bearing, itself, has frozen up somehow. Possibly, it gets 
moisture inside which freezes and gums up the werks; ask folks like 
K1TTT or W3LPL or other northeasterners how that happens. You should 
have a moisture shield over the thrust bearing to help keep moisture 
out, even if you don't normally get snow or ice up there, just on the 
principle of it.

73,

Steve K0XP