I've been able to piece together hirschmann antennas from odds and ends found in the junkyard. From my reading on its normal operation, once the antenna extends or retracts fully, the motor is suppose to "sense" the increased resistance at reaching the end of the run and cut off. My current rebuild worked fine this way, but recently I've heard the motor continue to run and make a grinding sound after the mast has completely extended or retracted. This is what happened to my old antenna & when I dismantled it to diagnosis it, I found that the teeth at the end of the antenna when fully extended or retracted were worn down as was the little silver guide roller next to the nylon antenna teeth. A consequence of the motor continuing to run. I then found that mounts for the screw gear atop the two, large gears had crumbled and the screw gear itself was loose.
I am assuming that if the motor cuts off as the resistance increases that some component in the new antenna assembly has become loose but I don't see anything obvious. I'm guessing at the moment that the drive belt between the motor and the screw gear is the culprit, but don't know how tight it should be if it was new, given I've got aged junkyard parts. Has anyone replaced this belt to know how tight it should be when new? Or any other thoughts on potential causes? .....Thanks!
I am assuming that if the motor cuts off as the resistance increases that some component in the new antenna assembly has become loose but I don't see anything obvious. I'm guessing at the moment that the drive belt between the motor and the screw gear is the culprit, but don't know how tight it should be if it was new, given I've got aged junkyard parts. Has anyone replaced this belt to know how tight it should be when new? Or any other thoughts on potential causes? .....Thanks!