[amsat-bb] Info on the G5500 elevation drive including bearing diameter

[William P Gravett <wgravett@xxxxxxxx>]

I pulled the elevation motor apart today after about 1 1/2 years of
service and am in a mess! The elevation pot is broken. It is a wire wound
500 ohm variable and only Yaesu seems to have them. The bearing races
were full except one bearing had fallen out and was rattling around  in
the case. I miked it at 0.312 inches and put it back in the race. After 2
years there was a little rust here and there inside but all in all,
looked pretty good.........UNTIL I tried to remove the four screws
securing the plate  on which the drive motor/gear assembly is mounted to
the rotor case. You have to take these four screws loose and remove the
motor/gear assembly mounting plate to get to the pot and it's wiring. The
screws are knurled on the outside and are a hex head  type. One popped
out ok using a hex wrench----the other 3 won't budge. I tried heating
with a Mapp gas torch----no joy. I have applied liquid wrench
penetrant---will have to see in the morning if that works.
Guess if I were going to make  recommendations to a new 5500 owner, so
far I would suggest the following.

1.) The feedback pots are pretty delicate. Try not to drop or bang around
the rotor.

2.)If you plan to do your own servicing for elevation rotor problems
later down the line, save yourself potential  headaches by opening up the
elevation rotor prior to putting it in service the first time. Remove the
aforementioned hex screws , liberally apply anti-seize compound and
reseat them.
I don't know about the design on the az rotor but it probably wouldn't
hurt to take a peek and look for a similar setup. 

3.) I might also add that the weatherproofing on my unit was in bad
shape. Get some clear or white silicone caulk and re-caulk the joints/
seams once you are ready to reassemble.

Merry Christmas and happy New Year 


Bill, W5PGZ

PS: Any suggestions on getting these other 3 bolts loose would be very
welcome. 

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