G5500 rotates clockwise when turned on

My G5500 azimuth rotator automatically rotates clockwise when control head is turned on. I’ve checked and double checked cable wiring. Disassembled and cleaned switches. Even cleaned and re-lubed all the bearings. It still turns clockwise anytime the on/off switch is turned on…pushing the right or left rotation switches has no affect. Any ideas on what’s wrong?

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Hi KE5GFJ,

Not sure if you have got your rotator working yet but there are a couple of thoughts. Firstly I am assuming that you have the old G-5500 with the AC motor and not the newer G-5500DC version.

If that is the case then the motors are driven by an AC signal between either pin 4 (CCW) or 5 (CW) and pin 6. I can’t remember the exact value. In the idle situation there should be no voltage on either pin 4 or 5. If you have voltage on pin 5 then the Relay RY-4 must be on….or you have a short somewhere in that part of the circuit. The relay can be turned on by a ground (0v) either the front switch or on the External Control port (Pin 2 does CW). I would make sure nothing is plugged into that port as a starting point….and there are no shorts to ground.

The circuit is pretty simple so my next step would be to download the circuit diagram from the net and check for signals going into the board. For the relay to work the transistor driving it must be working so it can only be a ground (0v) signal coming on the base of the transistor that is driving the relay.

See how you go.

John - VK4JBE

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