how to wire D-104 with W2ENY mod to FT-891

Discussion in 'Microphones, Speakers & Audio Processing' started by KA3BQE, Jun 13, 2019.

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  1. KA3BQE

    KA3BQE Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Pretty much the subject says it all. Acquired the D-104 with W2ENY mod and looking to wire it up to the FT-891 Yaesu. I don't need a lesson in why I don't want to use the D-104 with a modern radio. Just need instructions on how to wire this up. I'm finding bits and pieces here and there and tried to pull the instructions off the W2ENY site but I get page not found.
  2. K7MEM

    K7MEM Ham Member QRZ Page

    Yes, I get the same "page not found" if I try to get the instruction. However, I believe the following link is the same instructions, just from another site. Try this link to - W2ENY HiFi MIC ELEMENT Custom design upgrades Astatic D-104.
  3. KF4ZGZ

    KF4ZGZ Ham Member QRZ Page

    If you have the upgrade, you don't have a D-104 ..... you have a modern mic in a D-104 "case".
    I would contact ENY and ask about the wiring ..... the info looks a bit confusing.
    The instructions Martin posted says it was designed for a 3-wire cable and the pics show that, but the individual manufacturers line drawings all show 4 connections.
  4. KD8HLV

    KD8HLV Ham Member QRZ Page

  5. K7JOE

    K7JOE Ham Member QRZ Page

    Well, the FT-891 pin out is as follows off the modular plug:

    PIN3 PTT
    PIN4 MIC
    PIN6 + 5VOLT
    PIN7 UP

    Pin 2 and 3 on the Yaesu connect to the D104 push (or grip) to talk open/closure. It's a simple make/break set of contacts on the candlestick of the D104. Follow those wires down to the multi-point connection strip. It's 2 simple wires. if correct, when you grip (close) the contacts it should key the radio.

    Now that the radio is switching from rx to tx etc, now go in and get audio to the radio

    Next is to get audio to the radio from the mic element:

    The W2ENY modification requires what is called bias or phantom voltage on the electret element. Bypass the pre-amp in the D-104 if you have that variety.
    The W2ENY element should have two wires. An audio wire, and a ground wire.

    Pin 4 and 5 on the Yaesu FT-891 connect to the mic.
    Pin 4 is the MIC audio line. That goes to the positive side of the W2ENY mic element.
    Pin 5 is the MIC GROUND. That goes to the negative side of the W2ENY mic element.

    Last step...this mic element is an electret condenser and so it needs some voltage to bias / operate. We can get the voltage from a 9V battery or conveniently from Pin 6 on the yaesu 891.

    Do one of the following (not both)

    A. PIN 6 for bias voltage: Connect one end of the resistor (included with the w2eny kit) to the wire from Pin 6 to tap that 5V....The other end of the resistor connects to pin 4 (mic audio line).

    B. Other method 9V battery for bias voltage: connect the 9V battery + side to the W2ENY element and the - side to through the second set of key contacts that are normally open in the candlestick to to ground. That connects the 9V battery to the mic element each time you key the radio and disconnects the power when you are unkeyed. A 9V battery should last 3 or 4 years doing that.
    KA3BQE likes this.
  6. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

  7. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Any mic can be used with any radio with proper impedance matching, voltage or blocking capacitor (if needed).

    Always start by obtaining the manufacturers' spec sheets for the radio port and the mic. Don't trust wiring colors.
    KB0MNM likes this.

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