[TowerTalk] T2X Multiple failures, fix?

[Jim Thomson]

Date: Sat, 18 Feb 2017 17:57:09 +0000 (UTC)
From: DAVE WRIGHT <kanives at yahoo.com>
To: "TowerTalk at contesting.com" <TowerTalk at contesting.com>
Subject: [TowerTalk] T2X Multiple failures, fix?

?Greetings all,
I've been having a continuous problemw/my tower setup since installed in 1993'. I just can't figure it out. I've mentioned this online in the past, & received much helpf/hams/clubs & groups (K6EAG/TT/& NCCC) both local & abroad,thank you! However the system is still having the same problem; itseems incurable. :(
The system is: Tri-Ex LM-354 tower (54'HD crank-up, w/tilt-over base), that keeps eating rotors. The Yagi isa Mosley ?Pro-57b,? mounted on various mast lengths/strengths(both short & long), 2? OD/1/4" ID f/aluminum. Have also tried differingmaterials (both steel & thick-wall aluminum), w/a thrust bearing(used 3 in 23 years/both stainless-steel sealed bearings, &?open? bearings using marine grease (local salt-air/SF, CAbay-side.) I've been using T2X rotors mounted IN tower f/the start; & they eitherdon't last long, or quit immediately (last 2), ?right after? arebuild. 
Originally purchased the 1strotor new, & have had the last 2 rebuilt/exchanged several timesvia the two popular repair/rebuild shops here in the US. The onlypossible problem I can see from the ground is the Yagi ?swings? abit back & forth after done turning/brake initialization. (looks like the swing is too much?)
Other than that, nothing seen exceptwhen it starts to fail, it will not turn up on tower; even though itturns fine on the ground. That is, until it becomes ?stuck? forgood/then I send it off f/a rebuild. The repairs typically mention?brake failure.? I have since purchased the ?brake-delay?PCB, & the next rotor will have it installed in box. 
At this point I'm -almost- positiveit's an ?alignment? issue(?), but I'm not clear how proceed. Ihad assumed perhaps wrongly that once everything was bolted together,it's functional/should work. I have now been advised that assumptionmight be incorrect. If someone could point me to a link/site w/theironclad alignment procedure in writing/illustration/or video, thatwould be perfect.
When functional, the system worksgreat! =304 worked/277 confirmed. Most w/this system, & a fewwires/dipoles/ smaller Yagi's prior to this large Yagi. Problem is,it's been down more than 60% since installation. Never had theseproblems w/a small tri-bander; this just sucks! :( I'veabout given up; & haven't been on much at all. (99% HF.) 
This record of failure is justintolerable, & now that my age is getting up there w/healthissues, I won't be able to work on it much. Need help as itis. Any suggestions/troubleshooting discussion? I would be reallyhappy to get on air & try f/the last few ?rare ones,? &do a few more of the popular contests before kicking da bucket. :) 
Thank you all, 
Dave K6JOX 73

##  A pro-57, by itself is not a huge antenna.  The T2X  should not be an issue.  How many thrust bearings are you using ?  How far into the tower is the rotor ?  After reading the above, and with multiple failures, it may well be an alignment issue. The top bearing might be a tiny bit out compared to the main axis of the T2X, causing it to partially bind at some point in its rotation.   IF a 2nd thrust bearing is used, the chances of getting the rotor , +  2 x bearings all in precise alignment is difficult at best. IF a 2nd bearing is used, like just above the rotor, its set screws should not be tightened down.  Any 2nd bearing is just there to stop the mast  from deflecting inside the tower in high winds.   Is the very top plate and rotor plate parallel to each other ?   Is there a locking collar on the very top plate ?  UST uses a locking style collar, welded between the very top plate, and a 2nd welded  plate, just a few inches below.  Its used to lock the mast in place, IF the rotor is removed.

##  When your  rotor is removed for repair, how are you supporting the bottom end of the mast ?   If its just flopping about, it could put a slight wow, or bend in the mast itself, causing more binding when the replacement rotor gets installed.  
Jim  VE7RF