Potentiometer solution for the Prosistel / Bigboy rotators!
The blog has not been updated since last year and I figured it's time to start again! Summer is always a hectic period of the year for station maintenance. This winter we lost two potentiometers again in two Prosistel PST-71 rotators. This has happened many times and we are pretty much tired of replacing them because the process requires access to the bottom side of the rotator which means you have to take the whole thing down on the ground.
The construction is really crappy. The pot sits in a small space in the bottom of the rotator, the shaft of the pot is not mechanically de-stressed which means we lost several pots to mechanical breakdown. Another issue is that water easily collects at the base of the rotator making the small space below very damp and things start rusting. I know that many many others have had exaktly the same issues from emails and some videos on youtube. So I decided this time everything will be re-done!
I sketched up a new box that should be mounded below the rotator itself and by drilling a hole in the rotator plate a shaft can be inserted and run down in the new box. Got some help from Thomas SM0CXU to build the boxes and this last weekend myself, Thomas and Dag SM0KDG did the job. I have a gut feeling we will be pretty much problem free now for many years to come!
Here are some pics: