----- Original Message ----- From: "John" [email protected] To: [email protected] Sent: Wednesday, October 28, 2009 3:50 AM Subject: [amsat-bb] Yaesu G 5400 elevation rotator quit working

My Yaesu G 5400 Elevation rotator decided to quit working Friday morning.

I could press the up and down buttons and hear the motor running but the antennas would not move.

After being gone out of town for two days, I decided to try it again Sunday night.

And to my amazement, it worked. The antenna moved.

Anybody have any clues as to why this happens and what to do to fix it?

Thanks,

John C.

KE5GFJ

Pampa, Texas

Hi John, KE5GFJ

You probably are in trouble with the Elevation rotator for the following reason :

Each bearing is composed by 20 ball bearings size 0.312 ( 5/16 inch ) and a bearing holder.

One groove for the balls is casted into the aluminum boom shaft tube and the other groove is casted into the aluminum rotor housing

The bearing holder is a stainless steel toothed ring with 20 teeths and the purpose of it is to keep the 20 balls separated each other while holding the lubricant grease between them and lubricate the grooves during rotation preventing in addition the wather to enter the rotor housing from the outside.

The problem here is that the balls are not in contact-to-contact each other but they are separated each other by the teeths of the bearing holder in the sequence O-O-O-O-O-O-O............ and so on.

In this condition the vertical radial force generated by the weight of the antennas is not completely absorbed by the balls but is applied as well over the teeths of the bearing holder and so the 20 balls will be forced to separate away one from the other.

The load of the antennas is responsible to wear out, to deform and to cut the teeths of the bearing holder but as soon only one or two teeths are broken then the distance between the balls increases so that the big assembly tube gear has room to fall down a little bit into the grooves.

In this condition the distance between the assembly tube gear and the internal pinion increases up to a point that to engage the big assembly tube gear into the pinion fails.

If this is your case the motor runs in both directions but when the wear is at the beginning than the antennas becomes stuck time to time.

To cure this problem and prevent damages to pinion and to the assembly tube gear I have removed the bearing holder and I have filled the grooves with black molibden grease adding in it I do not remember exacly if two or tree more balls of same size and this was made in order to replace the room originally occuped by the teeths of the bearing holder.

My modified rotator without the bearing holders and more balls is actually running with no problems from several years now.

73" de

i8CVS Domenico