Hi Mike,
Grease is a mixture of oil and soap! Soap's main constitutients are caustic
soda,
lanolin or some-other fatty animal or synthetic oily material. Grease and
plastic often
don't exist well together. I suspect that the black tar may be material
leeched out of
the plastic, possibly carbonous based.
Flush the gear box well with a benign solvent, such as kerosene (paraffin) and
then wash
in hot soapy dish-washer liquid and dry in natural sun light. I have used
Castrol LM
grease satisfactorily for other jobs. Avoid the Moly types as they contain a
high
percentage of colloidal graphite which "loves" plastic!
Hope this helps.
John ZS5JF
----------
> From: Mike Baker <bakerhouse@uswest.net>
> To: Gilmer, Mike <mgilmer@gnlp.com>; AMPS reflector <amps@contesting.com>
> Subject: Re: [AMPS] Reduction Drive
To: <amps@contesting.com>
> Date: Monday, November 15, 1999 7:52 PM
>
>
> Hi Mike,
> In the past I have had good luck using wheel bearing grease. It is cheep
> and looks a bit like "Lubraplate". It is made to take high temps as well as
> low
> temps and generally will not gum up.
> Best 73
> Mike Baker KØQZ
>
>
> "Gilmer, Mike" wrote:
>
> > I'm trying to "restore" a pair of ARD230A amps. RF decks and PS seem OK.
> > They both make power. The few identified problems seem to be in the control
> > crap. Go figure.
> >
> > Amongst these problems, I found that one unit's motor drives (on TUNE and
> > LOAD caps) work OK, but the other's wouldn't turn when driven. I had a spare
> > reduction drive so I tried it, too: NG.
> > Turns out (after biting the bullet and drilling out the swages on one to
> > open it up) that the grease used to lube the gears inside the reduction unit
> > had turned tar-like. The innards have 6 or 7 gears - some plastic (motor
> > end) and some metal (at the output end). The grease around the metal gears
> > was what became tar-like. The grease elsewhere was still "normal". After
> > cleaning out the "bad" grease, the unit worked fine. I can even put the
> > drive unit back together :)
> >
> > Questions:
> > 1. What would cause the grease to "gum up" like this?
> > 2. What should I replace the grease with? (short of converting them to
> > manual tune, hi)
> >
> > Mike
> > n2mg@contesting.com
> >
> > --
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>
>
> --
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--
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