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G-5500 Rotor

Elevation Rotor Repair

G-5500 rotor before opening 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.

G-5500 Elevation rotor

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.

G-5500 Elevation rotor inside gearbox

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....

G-5500 Elevation rotor inside

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.

G-5500 Elevation rotor inside

Close look at the bearing, from the outside. One limit switch is also visible (a bit blury on the picture).

G-5500 Elevation rotor inside gearbox

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.

G-5500 Elevation rotor main boom

The main axle where the elevation boom is mounted in. The copper strip touches the end switches when mounted.

G-5500 Elevation rotor motor removed

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.

G-5500 Elevation rotor bearing cleaned

Dismantled and cleaned ball bearing. Each of the two bearings contains 20 balls.

G-5500 Elevation rotor bearing cleaned

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.

G-5500 Dismanteled gearbox

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.

G-5500 Azimuth rotor

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.

G-5500 Azimuth rotor

Overview of the wheels and axle of the gearbox, sorted in the correct order.

G-5500 Gasket and lubricant

New gasket and lubricant. In a few years we will see if these were the correct ones...

G-5500 Azimuth rotor

The gearbox cleaned and lubricated again.

G-5500 Azimuth rotor

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.

G-5500 new gasket

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

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:

Hello Ivo,

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
Michael Gamst

Schematic replacement capacitor for Yaesu G-5500 AZ/EL Rotors

Cool capacitor mod implementation by N3CRT Charles N3CRT built and installed the above "cool capacitor mod" into the elevation rotor of his G-5500 system. Because it might be helpful to others, here is the link to his design files, and the readme file for some explanation.

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