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Re: Elevation rotor jammed



Hi Alan. 

We have a similar problem with our G-5600 system at Henry Ford 
Community College, K8EEH, Dearborn, MI. Two weeks ago we took 
apart the elevation rotor and removed out the motor (with the gear 
attached). We found that the motor only spun in one direction, but 
the gear assembly was fine. We then disassembled the motor. 

Inside the motor assembly (below the gear) is an inner race (like 
that of a bearing) that holds a coil spring. This spring winds around 
the race with both of the ends bent inward. The bottom of the plastic 
gear piece is rectangular-shaped and contacts the bent ends of the 
spring when the motor turns. This spins the coil spring around and, 
according to Yaesu, serves as a motor end-stop safety. 

One of the spring ends on our system was broken. Removal of the 
coil spring from the motor assemly allowed the motor to spin freely 
in both directions. We then called Yaesu's service department and, 
with their help, ordered:

S8000377 Spring Winder
S8000376 Coil Spring
S8000379 Motor Pinion Gear

In addition, we ordered new screws for the rotor (the others were in no 
shape to be reused):

S8000220 Housing Screw with Washer  (QTY. 8)
S8000219 Gear Plate Mounting Screw & Washer (QTY. 4)

Then, while the thing was apart, we just ordered the ball bearings and 
bearing rings(it had been in service up on the roof of the college for 
over seven years):

S8000208 Bearing Ring (QTY. 2)
S8000209 Ball Bearing (QTY. 2, each sold as a set) 

The total cost of the parts above was $23.10 (US). Shipping was $4. 
I found Yaesu's service department to be quite helpful and informative 
on this rotor. 

We have yet to assemble the parts, since out access to the roof of the 
building is restricted and none of us have had the time to accomplish 
this task. The service technician at Yaesu warned me that the 
motor/spring/gear assembly had to be timed, once it is reassembled. 
I guess we'll find out about that part soon enough. 

Removal of the screws is not easy. Soak all of them in WD-40 (or some 
other penetrating oil) before attempting to remove them, especially if rust 
is visible. Even after this, the screws may need a little coercing. Tap the 
heads with a hammer several times to break them loose. Use a large 
phillips screwdriver and, if this doesn't work, Vice Grips can be used to 
slowly get them out. 

If you find any more information on the timing of the coil spring (or any 
other hints) please let us know. We are still undecided about the type of 
grease to use on the ball bearings. Old postings on this subject show that 
low-temperature grease is best, but no specs are given. People have told 
me that general-purpose bearing grease sometimes has a temperature 
rating of as low as -40F. 

Good luck and keep us posted

Mike, N8MR








At 07:09 PM 11/12/98 -0000, you wrote:
>Hi all
>
>I've got hold of a second hand Kenpro KR 5400, but the Elevation rotor
>appears to be stuck.
>
>Has anyone got any info or tips for taking the El and the Az rotor's in bits
>to clean them.
>
>Thanks all.
>
>Alan - G8UFN
>
>----
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
>

Mike
kf8bex@oeonline.com

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