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Elevation Rotor Repair
After only three years being outside, but rarely used, my G-5500 elevation rotor did not rotate any more. The cabling was still OK, and the rotor motor tried to rotate, but no rotation happened. So a new project was born, fixing my elevation rotor.
The problem seemed two gear wheels which were completely stuck on an axle of the gearbox, where they were supposed to rotate smoothly.
Elevation rotor repair links on the internet
(un)Fortunatelly, there is plenty of information to be found on fixing the elevation rotor. Some of the information which was useful for me, is listed below.
I took some pictures during the process of fixing, which might be helpful to others.
The elevation rotor before opening. Picture can be handy for the alignment when all parts will be put together again in the end. Some bolts are still in the housing on the picture. After three years it takes an incredible amount of force to remove them all (thanks to Frans for helping me!). So, add some lubrication to them as soon as possible if you want to ever open your rotor at a later stage. I replaced the bolts with stainless steel Allen/hex screws.
Opened up, one part of the housing removed. The rusted motor is visible, and the gearbox which drives the main elevation axle.
I guess my rotor was produced in July 2005....
The other part of the housing. It seems that the rotor housing is not entirely waterproof. Rust from the bearing is also clearly visible.
In the middle of the bottom part of the housing, a small hole is visible which should drain water from inside the rotor to the outside.
Close look at the bearing, from the outside. One limit switch is also visible (a bit blury on the picture).
The gearbox removed from the housing, also the four Allen/hex screws were extremely difficult to remove (thanks Ronald PA5RB this time for help). The grease in the gearbox is completely dried out, and dry remains can be found between the gear wheels. Also the two end switches (black) are visible.
The entire gearbox part has to be removed from the housing (as shown here) to be able to remove the main axle out of the housing.
The main axle where the elevation boom is mounted in. The copper strip touches the end switches when mounted.
The motor removed from the gearbox. I replaced the two small bolts by Allen/hex screws types. The black bolts are used to keep the entire gearbox mounted (one bolt is still mounted, the other three are in front of the rotor here.
Dismantled and cleaned ball bearing. Each of the two bearings contains 20 balls.
I replaced the balls from the ball bearing with stainless steel ones. Diameter size is 5/16 inch.
I bought the new balls at Brammer
in Amsterdam, The Netherlands.
Thanks to Richard G3RWL for pointing out that the balls are 'imperial size', after I discovered that 8 mm balls do not fit well.
Front plate of the gearbox removed. The front plate is mounted with the three screws which lay in front of the rotor here. The gear wheel on the left is directy fitted to the elevation position potentiometer.
The two wheels in the middle of the picture caused the elevation rotor jamming. These two wheels are supposed to rotate on the axle, but in fact they were stuck completely.
Overview of the wheels and axle of the gearbox, sorted in the correct order.
New gasket and lubricant. In a few years we will see if these were the correct ones...
The gearbox cleaned and lubricated again.
The rotor cleaned and lubricated again. Eight new stainless steel socket Allen/hex screws were used to mount the two main parts together again. Take care to position the main axle correct back in place, regarding both the elevation position potentiometer and the end switch.
I added a new gasket (made of fresh smurfs) before closing the rotor again. Don't forget to leave the small hole on the bottom of the rotor housing (not visible here) free, to let the water out.
Replacement capacitor for Yaesu G-5500 AZ/EL Rotors
After this page appeared on the AMSAT-BB, I received a number of e-mails, one was of special interest about a 'replacement capacitor' for both the azimuth and the elevation rotor. I did not touch the capacitor of my elevation rotor during the repair session, but Michael Gamst of Circuit Design wrote this e-mail to me, including a picture and the schematic:
I have attached schematic and picture for a better (“super-cool”) capacitor I’m using in G-5500 (The original becomes very hot in both the AZ and EL rotor and can explode or just dry out). If you can use this information, feel free to distribute it (The components are from Farnell and the parts should not be altered).
Best regards / med venlig hilsen
© 2011 by Ivo Klinkert, PA1IVO - Contact