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Small variable capacitor with 3 ball reduction drive built into to fix?

Discussion in '"Boat Anchor" & Classic Equipment' started by AH7I, Dec 19, 2019.

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  1. AH7I

    AH7I Ham Member QRZ Page

    Older RX needs a Q multiplier.

    Problem with this old Heathkit QF-1 is:

    The tuning capacitor's built in reduction drive is slipping.
    It's a 3 ball affair. The outer race is stamped into the capacitor frame.

    The capacitor is not binding and turns freely.
    The pointer's set screw is clearing the panel.

    Is it possible to fix? Tricks? How?


    73, -Bob
  2. WB2GCR

    WB2GCR Ham Member QRZ Page

    Try cleaning the balls/race with solvent, maybe spray automotive solvent degreaser/brake cleaner.
    Then re-grease with the heaviest grade of grease you can find.

    Might work... :D
    N2EY likes this.
  3. N2EY

    N2EY Premium Subscriber QRZ Page

    What @WB2GCR wrote.

    What happens in old caps and dial drives is the grease gets so thick and chunky that the drive slips and binds.

    I would suggest removing the capacitor from the unit to do a thorough cleaning.

    73 es GL de Jim, N2EY
    WA1GXC likes this.
  4. WA1GXC

    WA1GXC Ham Member QRZ Page

    Good advice above x2. Excellent product for mechanical as well as electronic cleaning is

    CRC "QD" electronic cleaner spray available at any auto-parts chain store for $9.99 -large 11 oz. can.

    Leaves no residue and dry within 15 seconds. Highly flammable. Put a paper towel under the unit

    if you leave it in-place so you don't get a film of petro-crud on the chassis. Less expensive than professional

    electronic cleaner for non-precision uses such as non-RF switches, switch detent assemblies, audio connectors.

    N2EY and AH7I like this.

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