Ten Tec Omni C AF/Power control

Discussion in 'Radio Circuits, Repair & Performance' started by KA3YIA, Aug 11, 2021.

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  1. KA3YIA

    KA3YIA XML Subscriber QRZ Page

    I am looking for a replacement for the AF/Power control for my Ten Tec Omni C. I have been unable to find an original part or an aftermarket replacement. Any suggestions would be appreciated.
     
  2. W9GB

    W9GB Ham Member QRZ Page

    The Ten Tec OMNI-C used a Combination Power Switch and AF (Audio Volume) Control.
    As I remember the Potentiometer is 24mm (diameter).

    The Power Switch is PUSH-PULL. That assembly is on the BACK of the Potentiometer.
    The TenTec Century 21 uses the SAME Switch. $15 each, when TenTec sold them.

    Contact W3KW … who has repaired seven (7) TenTec radios.
    =
    3ECC1987-E79D-4551-A704-1D62EEE996EE.png
    PUSH-PULL (Power) on a Potentiometer
    It’s a standard potentiometer with an added, built-in switch.
    The switch is activated by pulling it out of, or pushing it back into, the rotary shaft of the pot.
    ==
    Used extensively in Music Industry (guitar, bass) — BUT the potentiometers are usually 250K ohm or greater. Amateur Radio normally uses 10K or 25K ohm AF controls.
    https://www.fralinpickups.com/2017/03/29/push-pull-pots-mods/
    ===
    IF you are not using the matching TenTec power supply with your Omni,
    THEN the front panel power switch will have no effect.
    The rig will be powered as long as there is output from the power supply.

    If you are using a TenTec supply, unplug the Molex power connector
    THEN Check the switch operation using an VOM / DVM (continuity) connected accross the middle row of pins.

    The Power Switch is connected to the two center pins of the 4 pin power connector.
    They turn on the AC voltage on the power supply.
    The radio will be constantly ON, Unless you use a relay to switch the DC power input.
     
    Last edited: Aug 14, 2021
  3. KA3YIA

    KA3YIA XML Subscriber QRZ Page

    Thank you so much for your assistance. I was able to locate a 10K Potentiometer with Push Pull switch on ebay. It's actually a Fender replacement. I do have the Ten Tec matching power supply. Should have the part in a few days.

    Thanks again.
     
  4. WB6MMV

    WB6MMV Premium Subscriber QRZ Page

    In case your ebay replacement doesn't fit; I have a parts Omni rig (model D) that I can pull the pot out of and send you. Its the standard pot with the off/on section as a pull/push section. It has the standard solder attach points.

    Ken WB6MMV
     
  5. KA3YIA

    KA3YIA XML Subscriber QRZ Page

    Thanks Ken. Should have the part on Tuesday. Now the fun job of removing the knobs that have been on for 30+ years and removing the front panel. I am also going to add a ground jumper to the front panel that Ten Tec recommended years ago.

    Thanks again,
    Don KA3YIA
     
  6. W9GB

    W9GB Ham Member QRZ Page

    A majority of the eBay parts will be for high volume usage (guitar/music industry).

    This market was large enough (and willing to fund special orders), that
    CTS created a specific product line, the Series 450G
    24mm Guitar Potentiometer
    https://www.ctscorp.com/wp-content/uploads/Series-450G-Data-Sheet-Rev-B.pdf
    CTS introduced a new push-pull potentiometer for usage in a wider variety of guitars.

    CTS Series 450 (standard)
    24mm Rotary Potentiometer
    https://www.ctscorp.com/wp-content/uploads/450.pdf
    ===
    24mm (old 1”) potentiometers are manufactured by 3 major companies.
    CTS (Elkhart, IN); ALPHA (Taiwan); BOURNS (Riverside, CA)
    ALL Three of these companies have expanded their 24mm products,
    due to music industry demanding & paying for Quality Parts (like 1950s—1970s).


    For the Ten Ten radio usage (AF/Audio Control),
    the Potentiometer Section needs to be AUDIO Taper (not Linear).

    For “Fit-n-Finish”, LOOK Carefully at the Potentiometer’s 1/4” SHAFT
    LENGTH (1/2” to 1-1/8”, o.125” increments) and
    TRIM (Round, Flat, Split Knurled)
     

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