[TowerTalk] Rebuilding an Alliance HD-73

[Brad Rehm]

Dan,

You've mentioned all the obvious things to check.  And yes, I'd apply a
little grease to the gear train.

I've overhauled a few HD 73s and found that the motor and geartrain assembly
can develop cracks.  At startup, the assembly separates and gets out of
alignment, making it harder for the motor to get started.  So when you get
the rotor apart, look for fractures.  Hold the assembly with both hands and
twist, lift, and pull.

73,
Brad KV5V
Jarrell, Texas

----- Original Message -----
From: Dan Levin <djl@andlev.com>
To: tower talk <towertalk@contesting.com>
Sent: Monday, June 19, 2000 12:51 AM
Subject: [TowerTalk] Rebuilding an Alliance HD-73


>
> My father had this rotor in service for about 15 years.  When removed from
> service, it was "sticking" quite badly.  That is to say that it would
refuse
> to start much of the time.  Towards the end, pretty much all of the time.
> Once it started it worked fine.  He built a voltage booster for the motor
> line, which was moderately effective in improving the situation.
>
> When I removed this rotor from service, it tested out fine on the bench.
I
> stuck it in a box and forgot about it.  Now I need it to rotate my lower
> antenna for which I just built a sidemount this weekend.
>
> So I need hints for rebuilding an HD-73.  Suggestions of the form "send it
> to Norm" will be sent to /dev/null.  I would happily sent it to Norm, but
I
> am feeling cheap at the moment :-)
>
> I have removed the bearings, and cleaned them.  I will inspect them, and
> replace any obviously bad ones.  I will check the teeth on the various
> gears.  I will verify that the various circuits in the rotor check out for
> resistance.
>
> Anything else that I should check?
>
> What grease should I use when I rebuild it?  Should I only grease the
> bearings themselves (and their races, obviously), or is there anything
else
> that I should grease?
>
> The apparent cause of failure is "varnish" that has built up where the
upper
> part of the rotor mates to the lower part.  I will remove this "varnish" -
> should I lubricate this joint in any way?
>
> All hints appreciated.  Thanks!
>
>             ***dan, N6BZA
>
> P.S.  Don't forget the California QSO Party - October 7 and 8!



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