Turner Expander 500 Mic

Discussion in 'Microphones, Speakers & Audio Processing' started by N1YNY, Jan 28, 2018.

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  1. N1YNY

    N1YNY Ham Member QRZ Page

    Used this power desk mic for many years. Worked great.

    Uses 9 volt battery.

    Did not use HF rig connected with mic for about a year now. Mic does not work now.

    Replaced the 9 volte battery.

    When key mic can throw carrier. Mic's internal meter moves properly (shows audio) but no audio to rig.

    No short in mic cable from mic to jack.

    Cleaned connections in mic jack to rig.

    Stock mic works proper with rig but not this Turner desk mic now.

    Anyone have any ideas what it could be or who can send to get fixed?

    Thanks and 73's.

    Pete, N1YNY
  2. W9GB

    W9GB Ham Member QRZ Page

    The Turner Expander 500 (NOS with the box) has sold as high as $400 USD on the auction sites. Typical asking prices by CB operators are $250 to $300.

    Turner Expander 500
    Version 2 of this microphone was mfg. for CB market -
    the last two years of Turner in Cedar Rapids.


    Turner Expander 500 microphone
    Specification Sheet and Schematics

    This microphone has an audio pre-amplifier (using transistors) in its base.
    You likely have “lost” (gone bad) one of those transistors.

    1.) This microphone should be repairable, by a component level electronics bench technician.
    2.) IDENTIFY which production version (V1 or V2) of the Turner Expander you own.
    3.) Repair will require testing transistors in this microphone pre-amp.
    4.) Bosch Audio/Telex does not perform service on 35+ year legacy Turner microphones.
    5.) There are numerous “wanta be techs” at many local radio clubs — avoid being their “test subject” with this Turner (making an easy repair a mess).
    Last edited: Jan 28, 2018
  3. N1YNY

    N1YNY Ham Member QRZ Page


    Your post is very helpful. Thank you.

    Few questions:

    1. How can I tell if the mic is version 1 or 2? Do not see any markings on it that identify.

    2. Been in the Carolinas for 17 years and not aware of any component level electronic technicians around here.

    4. Went to New England over holidays (where I am originally from) and brought to a ham/CB/SWL/scanner dealer who does repairs. Bought a lot of equipment there over the years. He checked the mic cord to determine no short, saw the meter moves when speaking and that a carrier can be thrown. He told me to sell on Ebay, let the buyer determine it does not work and deal with it. That is not my style.

    5. Not interested in shoemaker “wanta be techs” butcher it who has questionable proficiency. I could probably butcher it as well.

    6. Do you know of any reputable techs that I might get it to?

    Thanks again.

    73's and best regards.

    Pete, N1YNY
  4. W9GB

    W9GB Ham Member QRZ Page

  5. N1YNY

    N1YNY Ham Member QRZ Page

    Thanks Greg,

    I cannot read schematics.

    Appreciate your help.

    Pete, N1YNY
  6. DX146

    DX146 QRZ Member

    Hi sure you will find the turner expander 500 base is as follows.

    V1 no lock.
    V2 lock to talk if required.

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