A few days ago we had a nice Es opening and I was turning the big 50 foot plus long yagi around with my Prosistel PST61 (Green Heron RT21-D controller). Until this point things have been running very smoothly since I changed to using this new controller.
At one point I tried to rotate Clock Wise, and it wouldn't move at all. I tried Counter Clock Wise and it would move, but each time I tried to go back CW it wouldn't. I finally stopped when I was at 264 Degrees.
A few COLD DAYS went by with no change. Today it got up to 36F and I went up the tower. I checked the CW line loosened it's contact points on the rotor and on the Lightning arrestor. Then put it back together. I check the caps inside the arrestor and all looked like new.
Then I moved up the the main boom of the yagi and strong armed it a few degrees just wiggling it back and forth a bit.
My gut tells me the issue is the bearing needs greasing.
I came back down tried to turn the beam and it moves again.
Tomorrow when it's supposed to be even a bit warmer I'll run back up there and grease the bearing and fully rotate the yagi 360 degrees a few times. Hopefully that'll be the end of it.