[TowerTalk] Prosistel PST-61 or PST-2051 (a word of warning)

[K8RI]

On 5/7/2012 3:27 AM, Andy GD0TEP wrote:
> A word of warning about the PST61...
>
> The PST61 looks man enough to turn most large antenna systems, BUT, that
> large and strong look is let down by what you cant see...


>
> The main body of the rotator is well built, and, in principle, would turn a
> house :-)
>
> The main body is fastened (bolted) to the lower casting (that bolts to your
> tower) using only FOUR 1/4 inch machine screw, yes.. that's not a typo...
> 1/4 inch machine screws. The casting has no other locating pins, or
> interlocking castelations...  So, please have that in mind when you buy your
> rotator for your large antenna system....

I was turning this http://www.rogerhalstead.com/ham_files/Tower29.htm 
with the old style rotator until the top seal gave out. It destroyed a 
TB3 and TB4

>
> I have pictures of my PST61 once it had failed here:
> http://gd0tep.com/pst61/PST61.htm (and how i fixed it)

Do you have a photo of the 4 threaded holes straight on?

>
> The control unit main transformer is (in my opinion) under rated if your
> turning a large antenna... Where I am, the local contest group has 6
> prosistel rotator, a mix of PST61, PST51 and PST2051, and we've had FOUR
> transformer failures, after the first unit failed a second time, we pulled
> the 100va transformer and fitted a 150va.
I've had no problems with that in nearly 10 years.  OTOH when I first 
started out I only had a Ham IV which I figured would hold things if I 
didn't try to move the antennas in the wind. That failed in a few days.  
Then I tried the HDR300.  It lasted until I tried to move the antennas 
on a moderate windy day.  As soon as I released the brake the whole 
stack spun around destroying the 4 LMR-400UF pigtails.

Which control unit do you have. I have the digital read out with 
computer interface.  It's about a 200 foot run from control to rotator.

They now have a US distributor for information and maintenance/Warranty 
now.  http://www.arraysolutions.com/ so you no longer have to deal with 
the factory.

I believe they no longer use gear lube, but are packed with grease.  The 
rotator is very easy to work on and uses common parts *EXCEPT* for that 
large diameter bronze worm gear wheel.  After taking a bath in gear lube 
and making one whale of a mess I decided to make some changes.  (good 
thing I have a concrete floor with 5 coats of epoxy) out in the shop.   
If you wonder what the innards are like 
http://www.rogerhalstead.com/Gears.htm  On mine I think  photo 32 shows 
the 4 bolts that hold the base to the body adapter.

I think those bolts in mine are M5 rather than slightly smaller 1/4 
inch.  Next time  you have to rebuild one see if a machine shop can add 
another bolt between each of the present ones.   If you pack it with 
grease like I think the factory does now and I did in mine, there is no 
problem drilling straight through into the case. Thread the case, use a 
SS flat washer, lock washer, and then a nut (if there is room.  IOW use 
studs with lock washers nuts on each end. These bolts have to be tight! 
(without stripping the threads.)
Remember this is the old style rotator with the AC motor and top seal 
that can trap water.

73

Roger (K8RI)