[amsat-bb] Re: Kenpro elevation rotor repair

quadpugh@bellsouth.net quadpugh at bellsouth.net
Sun Sep 28 04:24:24 PDT 2008


Here is my $.02. First smell the motor. If the motor has burnt windings
you  can smell them. mesureesure the resistance
between the winding. If the resistance beteen the winding is roughly
the same
suspect the capastor in the control box. If something mechanical has
failed a visually inspection will reveal it. There a lot of parts in
there but is faitly intutive on how to assemble them.

good luck



 -------------- Original message from Roy <rdwelch at swbell.net>: --------------

> Hi Guys,
> My two cents worth.  It looks like Sebastian has made all of the 
> checks.  I assume the rotor will not move in either direction.  It's 
> possible that something had fallen into the gear train, jamming the 
> works but it does sound more like a bad motor.  Have you measured all of 
> the voltages and especially the resistance values on the motor leads as 
> shown in the owner's manual?  If the resistances all look good and the 
> supply voltages are good then I would check the resistance from each 
> motor lead to the metal case to see if there is a short circuit to the 
> rotor housing.  I'm not sure but in some countries RFI hash protection 
> has been added to the rotor circuitry consisting of small RF chokes and 
> capacitors mounted inside the rotor case.  For example, my Emoto rotors 
> don't have it but the versions sold in some European countries do have 
> it.  You might check to see if there is a similar thing in your rotor 
> and that there are no failures there.  I doubt that this is the problem 
> however.  Good luck.
> Roy -- W0SL
> Sangat Singh wrote:
> > Sebastian,
> >
> > I had a similar problem. In my case I found that the 24 volt motor had 
> > packed up.  Since I had another Elevation Rotator with the faulty pot 
> > sitting on my bench for half a century,  I swapped the motor and it 
> > worked.  The motor is easily removed.  Please remove the 4 screws that 
> > hold the motor and then try powering up and see if the motor works.  I 
> > suppose you won't have a spare motor. I am trying to get the faulty 
> > motor rewired.  Our local talent can do wonderful things. 
> >
> > You might consult Roy Welch who has a great knowledge on ailing Yaesu 
> > rotators.  I am sure he has seen this mail and may have some valuable 
> > suggestions.  Do share your experience if you manage to fix this problem.
> >
> > Opening nuts is a big problem and your Motor Cycle workshop should be 
> > able to help.  I got mine too opened that way.
> >
> > 73
> >
> > Sangat, 9M2SS 
> >
> > 2008/9/27 Sebastian >
> >
> >     Well I had been back on the birds for the last 3 months or so, and
> >     while I was getting ready for an AO-16 pass a few days ago, my
> >     elevation rotor on my Yaesu G-5400B stopped at about 10 degrees.
> >
> >     That's it.  It won't go back down or up.
> >
> >     So I checked the wiring on the rotor, everything appeared fine.  I
> >     removed the elevation rotor from the azimuthal, and took it inside.  I
> >     made a small patch cord to go from the control box to the rotor, but
> >     no luck.  All I get is the display of the elevation of about 10
> >     degrees, and I hear a little hum when I attempt to move it up or
> >     down.  This tells me that the potentiometer is probably good, and the
> >     motor is receiving power.
> >
> >     I've removed the small nameplate on the side, and there is no water
> >     inside, and I can see the ball bears; there doesn't appear to be any
> >     rust inside.  I also removed the terminal assembly in case one of the
> >     wire had come loose, or had a cold solder joint, but I didn't find any
> >     problems there.  Looking at the diagram of the rotor, there appears to
> >     only be a small 24 volt motor which turns this; along with numerous
> >     mechanical parts.
> >
> >     So the question is.  Before I send this to Yaesu, has anyone had this
> >     problem before, is it a minor one (something that I could fix myself),
> >     or is best left to Yaesu?  Before anyone mentions, Norm's no longer
> >     services these rotors.  The four 'screws' that hold the two parts are
> >     impossible for me to loosen.  I would have to use a vice, but I do
> >     have a friend with a motorcycle repair business who I'm sure could
> >     open it for me in 60 seconds.  To me, this looks like a jigsaw puzzle
> >     by looking at the diagram.
> >
> >     The rotor was in service for about a couple of years back in the early
> >     90s.  It then sat inside without any use, up until a few months ago.
> >     If the consensus is to send it to Yaesu, should I bother to send in
> >     the azimuthal rotor, or should I follow the "don't fix it if it aint
> >     broken" rule?
> >     _______________________________________________
> >     Sent via AMSAT-BB at amsat.org . Opinions
> >     expressed are those of the author.
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> >
> >
> >
> >
> > -- 
> > Sangat Singh
> > 53, Jln. Perdana
> > National Planetarium
> > 50480 Kuala Lumpur (MALAYSIA)
> > Mobile: +60122838873
> > Office: +60322787388
> > FAX: +60322738873
> > Skype ID: sukhija
> -- 
> Roy
> _______________________________________________
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