CDE Ham 4 Rotor Rebuild Questions

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K4ZOT, Sep 3, 2010.

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  1. K4ZOT

    K4ZOT XML Subscriber QRZ Page

    I have a CDE Ham 4 rotor that may need a rebuild. I need to remove the top bell section and check the unit. Can the top section (4 bolts) be removed and replaced easily or are there any special concerns or hints to be aware of before doing it. I just do not want to mess it up. I may open it up, clean it up and regrease and that's it.

    I have Googled and found some helpful information. But none as detailed as I would like.


  2. W9GB

    W9GB Ham Member QRZ Page

    Place the HyGain/CDE rotator in a container before removing screws .... less places for the ball bearings to go and get lost.

  3. KB0YYO

    KB0YYO Ham Member QRZ Page


    It might be to your best advantage to send it to Hy Gain (MFJ) for the factory complete rebuild. They may see things you don't know are bad and need fixing.
    Not very expensive either. Considering the alternative such as lost bearings, screws, and other lively parts.
    I am glad I sent mine. fast turn a round too.

  4. K9STH

    K9STH Ham Member QRZ Page

    There are 96 ball bearings in the Ham-IV. You definitely want to put the rotor in a box before disassembling. Otherwise, the ball bearings will go "everywhere" and finding all of them is VERY difficult!

    The Ham series rotors are very easy to service yourself. The real "weak" point in them is the ring gear. There are 2 ring gears now available, one is the original "pot metal" and the other is machined from steel. The steel one costs more but is definitely worth the extra cost. The Ham series rotors are famous for losing the ring gear on a regular basis. The steel one doesn't break like the "pot metal" one does.

    Clean the potentiometer which "runs" the meter in the control box and make sure that it is "seated" correctly.

    The motor starting capacitor in the control box goes bad on a regular basis. I stopped using the replacement ones that come from HyGain (mfj) years ago. You can get much better starting capacitors from electrical supply houses like Grainger that have twice the voltage rating and that cost about half what the "original replacement" ones cost. The starting capacitors that you get from an electrical supply house are larger in diameter but they fit into the control box without any problems. You do need to cut off the leads from the original capacitor right at the capacitor. Then install the clips that come with the new capacitor on the ends of those wires. The clips then "slide" onto the contacts on the new capacitor.

    Make sure and clean the area where the ball bearings go very well. Then use a good quality grease to lubricate the bearings when you put them back. Also, wipe off all of the ball bearings with a cloth, paper towels, etc., before putting them back.

    Inverting the bell housing before starting to reassemble the rotor itself makes thing a LOT easier.

    Rebuilding the rotor doesn't take any real skill, just pay attention to what you are doing. Also, don't expect to remain clean while you are doing the rebuild. I can assure you that you will get grease on your hands, etc.

    Glen, K9STH
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

    The suggestions already mentioned are good. Inverting the rotor before disassembling it is the right thing to do. I like to fasten the top mast clamp to a short piece of pipe and clamp the pipe into my vice that has a rotating head. That way, there's no way the rotor can get away.

    This is how I dealt with a dried-up motor-start capacitor in my TR44:

    Polarized electrolytics don't like reverse current. The rectifiers prevent this. I selected identical electrolytics from my junque box to get the value AND ripple current capacity needed. In my case, four did the job. On each half cycle, I have two capacitors in parallel; the other two operate on the other half cycle (and the first two are discharged). Diodes are rated 5A/50V. I used Schottky types 'cuz I had 'em and the forward voltage is low (ordinary silicon types would've been 'OK'). I could've gone to the 'motor start capacitor store' but what fun would that've been? ;)
  6. W9GB

    W9GB Ham Member QRZ Page

    The electrical appliance industry (as well as the automotive industry) adopted the crimp FASTON connectors
    (Glen's reference to "clips") as a replacement for hand soldering in electrical assembly and wiring harnesses.

    There are 2 common FASTON sizes 0.187" and 0.250" and
    then specific sizes based on the wire (AWG) that are are crimping the leads to.

    You will generally find 0.187 used on smaller toggle and rocker switches,
    while the larger 0.250" is found on larger switches, relays and motor start capacitors.

    You can find these FASTON terminals at Mouser, DigiKey and electrical section of your local hardware stores.

    BTW .... your local HVAC contractor/maintenance center routinely stock
    Motor Start capacitors for Compressor motors on residential and commercial HVAC units !

    Last edited: Sep 3, 2010
  7. K4ZOT

    K4ZOT XML Subscriber QRZ Page


    Thanks for the advice, but at this point I really need to know if I can unbolt the top bell housing in the vertical position and just remove the top section to inspect the inside and then replace it without any alignment issues? Will the ball bearings fall out from just removing the top section are they not held in place by retainer rings? I just want to inspect the insides before deciding to send it out for repair or use as is.

  8. K9STH

    K9STH Ham Member QRZ Page


    The ball bearings do have a retainer ring. Unfortunately, that ring doesn't do a very good job of retaining! I can assure you that the chances are VERY good that the ball bearings are going to go "everywhere" when the lower section is removed!

    Therefore, put the assembly in a box before you even "think" of removing the machine screws that hold the lower section in place.

    Glen, K9STH
    (who spent a long time looking for ball bearings the first time he took a Ham-series rotor apart)
  9. K4ZOT

    K4ZOT XML Subscriber QRZ Page


    Thanks Glen and everyone. I understand about removing the bottom section. But, my real question is if I remove the TOP section of the bell will I have the same ball bearing problem.

  10. W9GB

    W9GB Ham Member QRZ Page

    SEE the ball bearing in this corroded HyGain rotator -- top has been removed --
    these bearing are rusted/corroded in place -- so they did not move.


    Glenn -

    I can tell my the persistence of your questions --
    that you are a person who has to SEE the solution (and associated problems).
    HyGain TailTwister model shown in photo below.


    K5LAD -- took the PICTURES/PHOTOS for observation and understanding. Repair.htm

    TailTwister model

    George - WA2VNV comments:
    I wish to add a suggestion about the ball bearing fallout problem.
    On my sailboat, I have to clean/wash & re-lube the winches which also have a bearing fallout problem. In this case, having a ball or bearing fall overboard is a more serious problem than chasing balls around the dusty basement floor!
    One of the simple tricks is to use an additional box top (approx 12 x 12 x 6 in (L,W,H)) with a round hole cut in the bottom sized so that it just fits over the pipe & flange that holds the rotor in place during dis assembly. It will contain any/all parts and balls that fall out and also keep them clean.
    Then you can carefully transfer them to the other box top for inspection, cleaning, etc.

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