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Auto band switch cable for my FT 747 GX to FC757 tuner

Discussion in 'General Technical Questions and Answers' started by K8ESE, Jan 20, 2013.

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  1. K8ESE

    K8ESE Ham Member

    Hi fellow hams.....I recently picked up in new condition a Yaesu FT 747GX transceiver....also got the auto antenna tuner Yaesu FC 757AT in nice condition....It came with the cord that one end has the plug that coming from the tuner (good shape), and the other end of the cord has a rectangle shape plug that fits to the Yaesu FT 757GX tranceiver for automatic band switching and provides the power to the tuner.......This rectangle plug is the wrong fit for my FT 747 transceiver.....It takes an 8 pin Din connector to connect to the 747 transceiver....I checked the manual and this cord; with the proper connector for each end is "D4000019" ....I cannot find this cord anywhere...does anyone know where I can find one with the 747 8 pin Din connector?...If not, can someone provide me any information where I can get this cord modified for the proper fit.....Any information will be greatly appreciated....73 K8ESE
  2. W9GB

    W9GB Ham Member

    Amateur Radio equipment does not have Industry Standards such as those established by Intel for WinTel base computers since 1990. This radio and tuner have been out of production for about 25 years !
    TIME to put on your Propeller Beenie cap.

    1. The 8-pin DIN connector is an easily available part in Silicon Valley HRO stores, FRY'S or via mail order (Mouser, Digi-Key). The ACC2 9-pin Molex connector on FC-757AT is also a readily available connector.

    2. Yaesu FC-757AT Manual

    3. The Yaesu FT-747GX connection is NOT shown in the FC-757AT manual, however the schematic diagram does show the band selection lines routed to the ACC2 9-pin Molex connector.

    Probably best to call YAESU USA SUPPORT, for the correct wiring of that special cable (D4000019) --
    it will be your DIY project to build that cable !!
    Yaesu USA
    6125 Phyllis Drive
    Cypress, CA 90630 USA
    For Technical Support or Customer Service call, (714)827-7600 between 8AM – 5PM PST
    For Parts Department call (714)827-7600 (8AM – 5PM PST)

    Last edited: Jan 20, 2013
  3. W9GB

    W9GB Ham Member

    NOTE: READ PAGES 12 and 24 of your FT-747GX manual for proper internal S02 setting (1 or 2) when using the Yaesu FC-757AT.

    N4ATS - Yaesu D4000019 Band Control Cable schematic

    HERE are the PIN ASSIGNMENTS, from the FT-747GX Manual and FC-757AT Schematic.

    FT-747GX : BAND DATA (Rear Panel) : 8-pin DIN Circular jack
    Interconnection via Yaesu Band Control cable #D4000019 shown on page 13 of FT-747GX manual.
    1 - +13.8 VDC
    2 - TX GND
    3 - NC (not connected)
    4 - A : BAND DATA
    5 - B : BAND DATA
    6 - C : BAND DATA
    7 - D : BAND DATA
    8 - LINEAR

    FC-757AT : ACC2 (Rear Panel) : 9-pin Molex (0.062" pins)
    These lines go directly to CPU Board (#) of this radio.
    GEN/HAM (3) is not connected to 9-pin Molex connector
    1 - GND (1)
    2 - D : BAND DATA IN (7)
    3 - C : BAND DATA IN (6)
    4 - B : BAND DATA IN (5)
    5 - A : BAND DATA IN (4)
    6 - NC (not connected)
    7 - +13.5 VDC (2)
    8 - INHIBIT (8)
    9 - NC (not connected)
    Last edited: Jan 20, 2013
  4. W9GB

    W9GB Ham Member

    BTW, DO NOT hack or cut that cable for the FT-757GX, that cable is also rare.

    DIY BUILD A NEW CABLE, per K4ATS Diagram (Schematic).
    Yaesu D4000019 Band Control Cable

    THEN, READ PAGES 12 and 24 of your FT-747GX manual for proper setting of
    the internal S02 switch (1 or 2) when using the Yaesu FC-757AT.
  5. K8ESE

    K8ESE Ham Member

    Thank you very much for your help!.....I went to the local electronic store a couple of days ago to get the DIN connector (not the mini), and did a "test" plug in with it and it did not fit anyway.....I will check out that valuable information you have provided me.......thank you very much!!
  6. W9GB

    W9GB Ham Member

    YES, that could be an issue with the 8-pin DIN -- DIN Connectors:

    There are seven common DIN connector patterns, with any number of pins from Three to Eight.

    Three different 5-pin connectors exist, known as 180°, 240°, and 270° after the angle of the arc swept between the first and last pin.

    image.jpg image.jpg image.jpg

    Three different 8-pin connectors exist, known as 240°, 262°(DIN 41524), 270° (DIN 41326) after the angle of the arc sweet from outer pins.

    The MAJORITY of Amateur Radio Equipment uses the 270° version of 8-pin DIN connectors, BUT you need to check. The 262° is also referred to as the Horseshoe. Commodore used this version for their computer ports!

    image.jpg image.jpg
    Last edited: Jan 20, 2013
  7. K8ESE

    K8ESE Ham Member

    Thank you very much for your help!....I have been off the air for a few years...Just wandering, is there any modern day auto antenna tuner available that would work with my FT 747 with available band switching connection?...Just a thought if I fail on this project.....But you gave me confidence to work on this old project which I will try :)
  8. K8ESE

    K8ESE Ham Member

    Cable is constructed...everything works!...thanks everybody...73 de K8ESE Harold
  9. AB6YA

    AB6YA Ham Member

    Great job Harold! Can you share any info? I've got the same project coming up!
  10. W9GB

    W9GB Ham Member

    The shielded multi-conductor cable (gray insulation) for your DIY cable build
    can be purchased from Jameco or All Electronics, both located in California.

    All Electronics - 22 AWG, Multi-conductor cable

    Jameco - 24 AWG, Multi-conductor cable^prodPage~15^page~SEARCH%2BNAV

    Pay attention to the DIN connectors that you purchase,
    especially from Surplus houses or hamfest / computer store bargain bins.
    It is easy to accidentally pick up the Commodore version (262° DIN 41524, Horseshoe).

    K4ATS Diagram (Schematic) for DIY cable build.
    Yaesu D4000019 Band Control Cable

    Last edited: Feb 10, 2013
  11. AB6YA

    AB6YA Ham Member

    Thank you!
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