need help mic wiring

Discussion in 'Microphones, Speakers & Audio Processing' started by M6YAZ, Aug 30, 2013.

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  1. M6YAZ

    M6YAZ Ham Member QRZ Page

    hi all

    im trying to wire a yaesu md-100 mic to a yaesu ft-1900
    but cant get it to transmit.

    shorting the ground and ptt on the radio do nothing

    anyone know how to get it to tx ?

    radio mic socket

    origonal microphone for the radio

    yaesu md-100 mic schematic
    md-100 circuit.jpg
  2. KC8VWM

    KC8VWM Ham Member QRZ Page

    The MD 100 has 2 grounds. (pin 5 and 7 on the MD 100 mic connector)

    1 is intended for PTT GND

    The second one is intended for mic audio ground.

    You may have to combine and add them both to the GND pin on the modular mic connection to make it work.
  3. M6YAZ

    M6YAZ Ham Member QRZ Page

    thanks for that Charles
    but shorting the gnd and ptt on the radio socket
    does nothing, so need to find out how to make the
    radio TX first.
  4. KC8VWM

    KC8VWM Ham Member QRZ Page

    aThis sounds like the modular plug pins are not matching up to the intended wiring correctly.

    Confirm the wiring exiting the modular plug is in the correct sequence to the intended pins using a multi meter.

    Also ensure the modular plug is the correct type, with the correct number of pins to match the tranciever.

    Also if you are using some sort of networking cable as your patch between the mic and the rig, keep in mind that some networking cables don't go "straight through." Sometimes they invert the wiring connections on the pins, (Wire # 1 may actually be wired to Pin #6 and the entire wiring sequence might be backward to what you are thinking.) and that's why you need to actually confirm the wiring vs the pin connection to match the pins to the wiring correctly using a multi meter.
    Last edited: Aug 31, 2013
  5. M6YAZ

    M6YAZ Ham Member QRZ Page

    i used the same plug for cloning two of the radios together
    which uses the ptt and gnd wires for cloning.

    i think there's more to it than just shorting the wires
    some kind of signal/mV sent from the mic to trigger the TX maybe
  6. KE3WD

    KE3WD Ham Member QRZ Page

    If you are shorting the PTT directly at the mic jack and not at the other end of a cable, and if you have tried shorting it to both grounds with no result, the problem likely lies inside the radio itself and not the mic cable or hookup. At that point, it would be time to troubleshoot the radio to find out why the PTT is not working, often that is due to the first switching transistor after the jack being shorted, leaky, or otherwise in need of replacement.

  7. KC8VWM

    KC8VWM Ham Member QRZ Page

    More info needed.

    Do you have a stock mic and what does it do when TX'ing.?
  8. M6YAZ

    M6YAZ Ham Member QRZ Page

    yes stock mic in tx mode has no continuity between the tx and gnd

    (the radio works perfectly with the standard mic)
  9. KC8VWM

    KC8VWM Ham Member QRZ Page

    With the microphone disconnected check the following menu item.

    Press the MHz(Set) key and hold for 1 second

    Rotate the DIAL knob until you see "26 Lock"

    Press the MHz(Set) key again and rotate the DIAL knob until you find the item "PTT"

    There should be no "locked key" icon indicated on this menu setting.

    If there is a "locked key" icon, enable this setting to allow for PTT operation.

    Press and hold the MHz(Set) key and the radio will save the new setting.
  10. M6YAZ

    M6YAZ Ham Member QRZ Page

    Charles the radio is working perfectly
    it is not a settings issue,
    thank you for your assistance though :)

    The ptt connection on the radio mic socket is multi function
    it does clone, TX and also up & down.

    the mic seems to use resistors in the TX line to tell the radio
    what function to perform.

    I will report back tomorrow after some more testing.
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