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Re: [TowerTalk] rotor repair

To: "Gregg Seidl" <k9kl@centurytel.net>, <TOWERTALK@contesting.com>
Subject: Re: [TowerTalk] rotor repair
From: "K8RI on TowerTalk" <K8RI-on-TowerTalk@tm.net>
Date: Sat, 18 Nov 2006 23:03:11 -0500
List-post: <mailto:towertalk@contesting.com>
I decided to answer this on list and it's a relevant topic and there may be 
others interested in what's required.

>I have a pst-51,an old green one.I think the direction pot is bad.I'll have 
>to call Array Solutions to see if they will fix it.I bought it from the guy 
>who sold them before AS did,yes it old.I want to use it on my next tower 
>project.  Gregg  K9KL

My PST-61 would be about the same age.

Other than the pin through the shaft I think that is just a 10 turn, 10K pot 
(I'll have to check the value)although they only use between 1 1/2 to 2 
turns in the middle of the range.  Do you have the digital read out or the 
analog meter?  In either case I think it's the same pot.  You take the 
bottom cover plate off the rotator housing, carefully note the position of 
the pot shaft.  IE, turns count.  Take the wires off the old pot, solder 
them to the new one, position the shaft the same as it was on the old one 
and remount the pot.  There are more precise instructions on the web or I 
could send a PDF. (If I can find it)

A word of caution. make sure the top seal is protected so water can not 
accumulate on top of it. That was a fault with the early ones, but I believe 
has since been fixed.

Mine had the top seal fail and required a bit of extra work but it was still 
fairly easy to fix even if it did take a bit of machining to get rid of the 
corrosion on the main worm gear wheel shaft.
http://www.rogerhalstead.com/Gears.htm
I have not put together the photos for the reassembly and finished project 
yet. Some of those show the pot and positioning.

However I would suggest replacing the oil with Lithium grease, particularly 
in a cold climate. OTOH you do have to dismantel the rotator to do that and 
I'd not do that without instructions unless you are quite mechanically 
inclined. I did include step-by-step disassembly instructions on the link 
above, but I assume no responsibility if it doesn't work right for some one 
else.   If you do decide to take it apart be very careful of the seals and 
note the rotator top plate where the mast clamp mounts is pressed into that 
big worm gear wheel shaft. That shaft goes all the way through and has a 
slot cut in the other end for the position pot.  Don't try to drive the 
shaft out and do not use the bronze gear wheel for a rest when pressing it 
out.  That gear is cast in place on the steel center piece.  To press the 
shaft out takes a fork or U-shaped piece of steel that fits around the shaft 
and on which you can place supports to push against the steel on which that 
bronze gear is cast.  On the PST-61 the top and bottom bearings are standard 
wheel bearings 32009X (don't know what they are on the PST-51 but would 
guess the same or similar)  The other bearings are standard sealed bearings 
and all available from your local NAPA store. I didn't find any double lip 
seals, but the same size single lip are also available from NAPA. I'd assume 
a search on the net would turn up the double lip seals. These are standard 
metric seals.  BTW put an alignment mark across the top, side and bottom of 
the case so everything can be put back together pointed in the same 
direction. When bolting the rotator to the mounting plate is not the time to 
be finding the motor no longer fits in the right spot.

If you check with them they also have a mod (basically changing the motor 
cap size) on the 61. If they do the same on the 51 you might find the same 
or equivelant cap at your local hardware store.

Also check the motor. Some of the early ones are open so water can get 
inside. Mine is sealed with a fan on the end that blows over the fins.  I 
believe older ones brought air through the inside. They do have a fix for 
that as well.

I should check. There is a brand new PST-71 just a couple miles west of me 
that I don't think has ever been out of the box.

BTW all new bearings, seals, grease, and cleaning solution ran about $100. 
I'd guess I have about 5 or 6 hours of labor invested plus about one hour on 
the lathe.

Good Luck,

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com

> ----- Original Message ----- 
> From: "K8RI on TowerTalk" <K8RI-on-TowerTalk@tm.net>
> To: "Gregg Seidl" <k9kl@centurytel.net>; <TowerTalk@contesting.com>
> Sent: Saturday, November 18, 2006 5:28 PM
> Subject: Re: [TowerTalk] rotor repair
>
>
>> They are a pretty straight forward rotator for the most part and with 
>> only a
>> couple of exceptions use standard parts.  There are differences between 
>> the
>> old green ones and the newer ones.
>>
>> If you contact the US distributor they do have some one who rebuilds 
>> them.
>>
>> I have the older PST-61 and rebuilt it myself with a couple of additions
>> such as replacing the oil with white Lithium Grease  and adding a shield 
>> to
>> keep water off the top seal.
>>
>>
>>> Is there a company who repairs PRO-SIS-TEL rotors?   Gregg  K9KL
>>
>> Which model and what seems to be the problem?
>>
>> Roger Halstead (K8RI and ARRL 40 year Life Member)
>> N833R - World's oldest Debonair CD-2
>> www.rogerhalstead.com
>>>
>>> _______________________________________________
>>>
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