Shure 526T Series 2 to a Icom 765

Discussion in 'Microphones, Speakers & Audio Processing' started by VE7GMX, Jan 11, 2019.

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  1. VE7GMX

    VE7GMX Ham Member QRZ Page

    Anyone wire the two ? Looking for some feedback .

    Anyone here ever wired a 526T to an Icom 765 ? In the guide there are so many options but I'm assuming the Icom is grounded switching ?? I used Pin 1 to Audio , Pin 7 to Sheild, Pin 6 to RX and Pin 5 to TX . I reversed 5 and 6 to test it but made no diff. This should easy but.....

    Thanks for any insight :)

    Link to the User Guide / Manual >
  2. W9GB

    W9GB Ham Member QRZ Page

    Usage of Rx switch line (526T) is ONLY used in Public Address applications OR
    ancient CB radio usage that required a receiver / speaker muting function.
    The Shure 526T Super Punch microphone was introduced in 1970s during later portion of the CB Craze ... SO many of these used microphones have been modified or abused (retiring, botched repairs, etc.) for various applications (CB, Public Address, Taxi, LMR, Dispatch).
    It is RARE to find a “NOS factory unit” today.
    Careful visual and electrical inspection (assessment) of used units will reveal current condition.

    The Shure 526T Series II model was discontinued in 2002/2003,
    with AES Milwaukee selling last inventory in 2003.

    I have had this Shure model, on the tech bench, many times.
    FIRST, determine IF all the parts are there.
    Common to discover these items missing: Microphone elements, Pee-amp board OR
    these items damaged: PTT switch, cut cord or loose wires.

    VTVM, VOM, or DVM (continuity function) can verify the
    microphone’s Push-To-Talk (PTT) wires and functionality.

    Shure Support Page
    Shure 526T Super Punch and Shure 526T Series II Wiring (Amateur Radio)

    Shure R96 Microphone element
    Icom IC-765 Instruction Manual (PDF)
    4-6 Microphone Connector, page 17

    PIN 1 - MIC Hot, NOTE: +8 VDC on this line for Icom Elecret element microphones
    PIN 7 - MIC Ground (Shield)
    PIN 5 - PTT Hot (usually positive DC voltage from radio)
    PIN 6 - PTT GND
    COMMON WIRING ERROR (Mirror image numbering by Asian mfg. since 1970s)

    The PIN number diagrams (manuals) are referenced looking at Front of Radio (MIC Jack).
    From the Microphone Plug, from the Cable Entry to plug ... looking Forward.
    Last edited: Jan 11, 2019
  3. VE7GMX

    VE7GMX Ham Member QRZ Page

    Thanks Greg

    Interesting about the RX line , that may be my issue . This mic hasnt seen a lot of use , the PTT and variable pot seem nice and tight , like it just came out of the box . It came to me with a 2 pin plug on it so assuming it was on an older rig . Element is there , inside it looks brand new , no weird looking solder or splatter or what looks to be added caps or resistors , as to the best of my knowledge . I've wired quite a few mics up to my Icom so I'm positive I have those connections correct for the rig. The Shure has DC decoupling so wasnt concerned about the 8 volts .
    Think I'll remove the black and see what happens and report back . Thanks


  4. W9GB

    W9GB Ham Member QRZ Page

  5. W8AAZ

    W8AAZ Ham Member QRZ Page

    Aren't alot of Icoms made to work with an electret mic? Thus a dynamic mic would have lower output and also, since it has DC bias on the mic line, you would need a blocking cap with a dynamic microphone. I guess it comes down to does the radio have the extra gain in the mic preamp.
  6. W9GB

    W9GB Ham Member QRZ Page

  7. VE7GMX

    VE7GMX Ham Member QRZ Page

    After tackling this , here it is :

    Pin 1 to WHITE
    Pin 7 to SHIELD
    Pin 6 to BLUE
    Pin 5 to RED

    This works !

    Yellow and Black not used

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