Icom 706MkIIG

Everything for ’706 Lovers in One Place.

© 2003-2015 by Harold Melton, KV5R. All Rights Reserved. Rev.04/26/15

Shop for Icom radios here.

2015 Update

I finally located a used main board (the one with the IF filters, processor, etc.) and repaired my 706MkIIG, which failed several years ago. Now it works like new! The used board was $250, but I figured, hey, without it the radio is worthless, but with it, it’s worth about $900 (incl. sep. kit and FL-232), so why not just fix it and get back on HF? And maybe later, sell it (and some other stuff) and get a 7100 or something…


Ah, the li’l 706: What can I say? I like it! It performs like big radio, but it’s small. It sounds good, and it’s well made. You can add the remote kit and put the control head and the radio body where ever you want them. They are reasonably easy to expand, calibrate, and connect to a computer.

This series of articles is a handy compilation of most of the mods and stuff I have developed or found on the web for the 706MkIIG, plus a chronicle of the little accessory kits that I have built to enhance my enjoyment of the 706.

2011 Notice: These pages have been divided into several pages for easier searching and linking to specific topics. Feel free to link to any and all pages. All KV5R articles are copyrighted and may NOT be reproduced in any other web site, but may be printed for personal and non-profit use, such as Ham clubs and classrooms, provided that links and attributions remain intact. These articles contains several schematics and kits designed by others. They are fully attributed and I make no claims upon them.

Disclaimer: The author assumes absolutely no responsibility, under any circumstances, for what the reader may do with this information. Building and connecting circuits, and performing adjustments or modifications, may damage your radio, void your warranty, and/or cause it to operate in violation of FCC rules and Type Acceptance, etc, unless you are very careful.



15 thoughts on “Icom 706MkIIG
  1. I am using my old ic706mkiig in my emergency go box. I have a Timewave TNC and am running it to my MacBook Pro.

    For packet I use a simple terminal program and it works just fine, it is plugged into the radio’s mini-DIN plug on the back, this has been working just fine.

    Now my dilemma, I have another interface that I want to use with Fldigi because the local ARES uses it with EMBEMS. The interface I have uses the VOX to trigger and to date, I cannot get it to trigger, and I am using a usb/serial adapter and no Civ. I do have it, but never thought about bah

    • If you mean your soundcard interface uses the radio’s vox, it won’t work on the 13-pin aux input, as the 706 audio input on aux jack bypasses the vox circuit and you must use the mic jack as input to use the radio’s vox.

      If your interface has its own vox circuit, it should work; an external vox should ptt via the aux jack.

      Either way, all you need is audio lines; you don’t need a serial port unless you want hardware ptt and/or civ.

      Note that fldigi is the one program that will not civ and ptt on the same port. You could use hardware ptt via your usb-serial adapter, then use a usb-civ adapter for civ if desired. Import usb-civ adapter/cable gadgets are ~$25 on ebay etc; they present to the computer as a virtual serial port, different than the one presented by your usb-serial adapter, and thus will work with fldigi.

      Also check the “hsend-sel” in the setup menu; it determines whether the ptt pin in the aux jack works for hf, v/uhf, or both. I don’t know what it does with the 8-pin data jack’s ptt line. See the 706 User Manual.

      See also the interface page in this series. A couple schematics there might get you going.

      73, –kv5r

  2. Hello,

    Here’s a strange one. Listening to cw there is an intermittent dropping of the tone which sounds like you are listening to cw on am. This is kind of a raspy, hissing sound and not a pleasant cw note at all. Can’t really predict when this will happen but usually in the middle of a cw qso and then it will go back to normal just as un predictably. Other modes seem to be okay. Transmit is good.

    Any hunches, theories or guesses are appreciated. Are parts available for a radio this old. Is this repairable?

    Thanks and 73,

    Ed, W8EO

    • I’m guessing you don’t have another CW op very close-by that’s overloading your receiver? Otherwise, might be a dirty relay contact on filter board; probably gonna need a tech to put it on the bench. I think most parts are still available, but fixing a serious problem is usually a matter of swapping out one of the boards, once the problem is located, since almost all the parts are SMT. They aren’t cheap, $100-$250 per board (used pulls via Ebay).
      73, –kv5r

  3. Dear friend, Need your help…my ic 706 mk2 is completely deaf on all bands and there is no tx power either. I hear the relays click while changing the bands. Best regards vu3npi

    • Only thing I can suggest is, make sure you don’t have a wide/narrow filter selected that isn’t installed. Otherwise, you’re gonna need a radio technician to put it on a bench and test it out. Also make sure they do a full “factory” alignment, per the service manual, after fixing.
      At least your filter relays are clicking! That, and ability to operate the display, means your 8V system, main processor, and master oscillator are working.

  4. Hello..My 706 doesn’t go to full power on some HF frequencies.With a dummy load attached,I get barley any power at all on the upper hf bands.I wired a Signal link USB unit to my radio&found that I hooked up the jumpers on the the signal link incorrectly.Think that might have damaged something.Help me out?Thanks

    • Sounds like a filter board problem. You should hear relays clicking when you change bands; those are the various output bandpass filters clicking in. If not, its trying to push RF thru the wrong filter, hence, very low output.
      But I can’t see how wiring a Signalink wrong would damage the filter switching circuitry, unless the ACC jack has a pin that signals bandswitching (for an amp) and you accidentally put 12v on it and blew something like a pin diode in the filter control circuitry.
      You’re probably gonna need a repair shop.
      73, –kv5r

  5. I need the front detachable panel for the icom 706 mkiig.
    My display on the panel all of a sudden got a burnout and the display is difficult to read.
    Kindly email me on callcyrus@gmail if any one wants to sell the front panel only

  6. Anyone know where I can get one of those little knobs for this radio? One popped off in the car and I can’t find it. Thanks much

    • hi
      you can buy the little knobs from icom uk,
      buy the pair as they have a little red mark on them now,
      they are about £1.50 each.
      regards paul

  7. I have the icom 706mk2 and will be using it on 2 meters as my base at the qth. wondering if you could e-mail me a easy step by step of setting up this radio for 2 meters. off set, plls tones, split, memory, scan, ect. i got it to trans. and worked one of our local repeters with a good report. just wondering? tom, kf4csu

  8. Hi!
    I had a bad accident with my ICOM 70MK2G and both potentiometers from front panel need to be replaced! How to get them? On e-Bay I found other things! Pse help!

    • You need to either disassemble the front panel and get the part numbers off the pots, or from the 706mkiig service manual (free online), then contact an Icom service center. But Icom parts are expensive so first try to find OEM equivalents from mouser or some other big parts supplier.

Leave a Reply

Your email address will not be published. Required fields are marked *