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HyGain Tailtwister T2X rotator repair            September 2012

The HyGain T2X rotator is a simple, fairly rugged rotator which is in use world-wide. It has a few design problems, but generally speaking is reliable, if serviced regularly.

Some things that could be improved :  (1) electrical connections to the rotator - poor - started off as an 8-way terminal block - the stainless steel screw threads were easy to damage and you never really felt that you were making a reliable long-lasting connection. Unfortunately, the plug and socket on newer (and current) versions of the T2X is only marginally better - the plug/socket arrangement is not waterproof and many wiring faults are due to corrosion in this area.   (2)  internally, the rotator needs a lot, but not too much, lubrication. The specified 'thimble full' of grease is not nearly enough - if the lower ball-race grease dries out, the ball-bearings will rust and the rotator will grind to a halt. (3) the potentiometer is a fragile and expensive item - if you dismantle the rotator and don't take sufficient care when reassembling, the potentiometer is easily damaged. You also have to make sure you align all the different parts carefully when re-assembling.  (4) lubrication of the wedge brake is crucial - often the grease dries out and hardens, causing the wedge brake to stick. Carefully clean off all old grease and replace this grease every time you have the rotator dismantled.  (5) overall, the T2X depends too much on having low-resistance wiring - this means extra expense if you have long cable runs. Remember - you can use 6-way cable if you remove the start capacitor from inside the Controller and mount it next to the Rotator, with short wire connections (pin 4 = blue wire from inside rotator and pin 8 = red wire from inside rotator)

This is the third time I have had to carry out this repair to a T2X, so I thought I would take some photos and create this webpage.

In strong winds, with a large antenna, the T2X gear-ring and/or spur gears can be damaged. The gear-ring is made of aluminium alloy and the spur gears which turn it are hardened steel, so more often but not always, it is the gear ring which is damaged.  (Click on any of the photos below for a full-size version)

p1050852a.jpg (661771 bytes)  gear-ring damage - you can see one tooth has broken off completely and several other teeth to the right are damaged


p1050856a.jpg (680798 bytes)  spur gear damage (one of the stacked pair which turn the gear ring) - one broken tooth.

p1050863a.jpg (966657 bytes)    broken spur gear shaft

Unfortunately, these damaged gears can cause one or other of the two steel shafts which hold the spur gears to bend (or break) - these shafts have to be straight or the replacement spur gears may jam or not work properly. You can buy new spur gear shafts but replacing these shafts is difficult - they are pressed into the alloy casting and have to be punched out from below - in some T2Xs there is no sign of the lower end of the shaft so presumably you would have to drill a hole to find the end of the shaft before you can punch it out. 

The GM3WOJ solution to this is my non-patented T2X gear shaft straightening tool !

I found an old (M15 x 100mm approx) bolt - the steel of this bolt seemed fairly soft, so I drilled a central hole - 6mm diameter and at least 32mm deep. Using plenty of oil inside the bolt hole and on the bent gear shaft, I used a 2lb hammer to gently but firmly tap this old bolt onto the bent shaft. I did this 3 or 4 times, going further onto the gear shaft each time, until the whole gear shaft was inside the hole in the bolt. I used a pair of Mole grips to ease the bolt off the gear shaft each time. This process forces the gear shaft to become straight.  CAUTION - do not hit the bolt too hard or you could crack the aluminium casting around the gear shaft.

Next I used a micrometer to compare the distance between the tops of the 2 spur gear shafts to the spacing of the 2 holes in the motor mounting plate - you may need to put the special bolt back onto a gear shaft and tap it gently sideways to be in the correct position. The motor mounting plate should fit easily onto the tops of the 2 spur gear shafts and the 3 mounting pillars.

p1050858a.jpg (436027 bytes)    GM3WOJ special non-patented T2X gear shaft straightening tool

Spare parts for the T2X are available from Craig at

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