Alliance U100 antenna rotor

It's not a "stop switch", every time the contacts close, it actuates the solenoid in the control box & advances the dial by 1 detent.

Jerry

Your 5-terminal rotator unit is likely model C-225. It's definitely a solid state control box, and can't be modified to control a U-100 rotor. The rotors are different inside; the U-100 rotor having a reversing capacitor and the motor, the C-225 having the motor and a position-sensing potentiometer.

Go to

and download the Alliance Antenna Rotor Service Manual and you'll be able to see the details of both models, and why they aren't compatible.

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David
dgminala at mediacombb dot net

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Thanks very much for that link Dave. I had no idea that Alliance made so many different types of rotors. In every new antenna installation I ever did I always used a U100. The funny thing is in all these years of mixing and matching old four terminal stuff I either picked up or had lying around I never had a problem getting a box/control combo to work. But after looking at the schematics I guess I've been extremely lucky. It's truly a shame they went out of business, They had the best product for TV in the industry. I never had to climb up on someone's roof even years later to replace a defective Alliance rotor. The current Chinese Channel Master is a real POS. I wouldn't even install one for a customer. Lenny

I had to, quite a few times to replace the soft seal on rotors that were 25+ years old. I would pull the rotor, replace the old screws with stainless, clean and relube the bearings. If it had the open pot to drive a meter for position I would clean the resistance wire & sliding contact, and use GC Tunerlube on the wire. Add a new non polar electrolytic to the control box & replace the old wire between them, and they would run another 25 years. :)

Some I serviced were so old that they simply had a lamp to tell you that the rotor was at the end of it's rotation.

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You can't have a sense of humor, if you have no sense.

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When I was a teenager I found one of those old rotors on the roof of an apartment house near where we lived in The Bronx. A friend who was a Ham radio operator gave me an old control box to operate it. The control box put out the correct voltage to operate the motor but the system had no position indication. I believe they were mismatched. This motor had a stop switch and a small aluminum "chock" that would jam the motor if it tried to go further than 360 degrees. I removed the chock feeling that it was an unhealthy thing to do and installed an indicator light circuit wired to the stop switch contacts in the motor. The light would come on as you approached 360 degrees from either direction. I'm 65 years old and am still using that rotor/box combination. Can't say enough about Alliance equipment. Lenny

They were one of the best, along with some CDE rotor models. The Channel Master/Radio Shack rotors were definitely lower quality. I saw a lot that were under five years old that were just plain worn out. I replaced a lot of AC capacitors in the CDE rotors, and worn out or cracked ball bearings.

I had a spare U100 control box housing, and made a nice test speaker out of it. A piece of cloth cover wire mesh for the grill over a good quality 4" speaker, and a line transformer. A pair of DPDT switches let me select 4/8 ohms or 25/70 volts at a half watt to service the building wiring of school intercoms.

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You can't have a sense of humor, if you have no sense.