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Richy N2ZD
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Hi Rich here,

A pal of mine stopped by with his ATAS 120 and he was complaining that it often stopped mid way and made a thumping noise refusing to go up. I tried all of the usual stuff like removing the sheath and cleaning and relubing the coil etc and it still thumped and refused to go up.

I wondered if the clutch mechanism was giving up the ghost but upon disassembling the unit, the true problem was revealed.. The Black threaded ring at the base of the coil form was stripped, this ring is what the antenna drive threads into to move the coil up and down.
Kinda cheap and cheesy if you ask me (a small, pressed in brass collar would have been better)

Anyway, the ring is glued to the coil form and you know what that means, the whole assembly must be replaced..$$$$

Being a ham and knowing I would lose a QSO friend for a few weeks, I then came up with a plan.. Re-assemble the antenna innards outside of the black sheath and align the inner unit so that the brass threaded shaft is true and aligned with the top unit. In other words the antenna inside should be assembled outside of the black tube and have the threaded rod screwed into the black ring (even though its stripped it should still thread in somewhat, just make sure its poking thru the top of the black threaded ring and that the silver alignment shaft is seated into the hole on the antenna top (the aluminum unit containing the fingerstock and ball bearings for lack of a better word).

Once you have the unit set up properly and have removed all lubricants, fire up the old propane torch and carefully (I MEAN CAREFULLY) heat the brass rod just far enough away from the plastic ring to cause it to re-form around the shaft. If you smell molten plastic, its safe to assume you've heated it enough, dont over heat anything remember the metal is a conductor and guess whats at the bottom of the shaft.. More expensive stuff, so take your time.

Once you have heated it and it reforms and cools somewhat, twist the brass threaded rod so it cuts new threads into the plastic ring.

Once everything functions ok, relube, retube and try it out!!

If you have any questions, email me

73's Richy N2ZD

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UploadedDescription
02-11-2006ATAS 120 Drive unit repair (stripped black drive ring).    (Selected article)
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