Everything for ’706 Lovers in One Place.
© 2003-2018 by Harold Melton, KV5R. All Rights Reserved. Rev.03/09/18
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.
People keep asking me how to fix their 706. I am not a radio technician! If your radio is broken, and you've done all the usual checks, you need to find an Icom service tech.
This is not a buy/sell/swap parts site. Please go to ebay, eham, qrz, etc, classifieds to look for parts. Comments about "parts wanted" will be deleted.
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.
My 706mkiig started now with freezing after a while or in the middle of transmit with FT8. All controls and push buttons are then out of action until you have unplugged the power and reconnect again.
What can be wrong
No TX on FM
This happens after the rig has warmed up and I have tried the following procedure recommended by Chris:
“There is a variable capacitor C1022 which needs to be adjusted until the voltage across the varactor is in a normal range. This sets the free run freq. of the PLL oscillator. The voltage at test point CP 1011 needs to be at 1.8 volts at full power transmit in FM mode on 10 meters.”
This works for a while but then the problem returns later.
Do you know where I can get a full set of flex CIRCUI connector cables for IC706 MK2G thanks Barrie
Hi, Barrie. Here is a link to ebay for a complete set of cables for the IC706MKIIG.
My IC706 MK2G is shutting down by itself, before the shutdown time was very long, now it is very close… does anyone know what it can be? 73′ PS8ET Joe
Very common problem, with many causes.
1. Connector between head & body must be clean.
2. PCB corrosion under the black rubber vibration pads. The most common place is under the MAIN board (the one with the filter), underneath, in the corner of the notch by the fan. Early ones used a corrosive glue. If traces are corroded they must be cleaned then jumped with tiny wires. Work under a 10-20x microscope.
3. Ribbon cables corrode in the connectors. To remove a board, you must remove ribbons. Some connectors are force-in, some have a tiny plastic piece that must be raised to unlock them. Use curved hemostats, and take great care to not damage the metal film conductors of the ribbons. Also the clear plastic stiffeners on ends of ribbon cables; glue fails and they fall off. They must be carefully glued again, in a very precise, exact position. Each ribbon is a custom part and I doubt any new ones are available.
4. There may be other causes, I don’t know. Maybe the relay on the PA board, near the fuse. Maybe the fuse itself is internally cracked. Maybe the SMT transistor that drives that relay.
My 706mk2g had that problem from its second year on. I tried to repair it many times. I never found the problem and it is now junk.
Hi, Harold. I had an unusual problem with my 706MKIIG and found a solution that I’d like to share. The radio worked perfectly after repairing a feedthrough for the HV5 regulator trace on the PLL board. Perfectly, except low sensitivity on the 144-148 band only. After troubleshooting for components for hours, I decided to go to the ADJUSTMENT SET MODE to see what was there and to calibrate the “s” meter. I stepped through all settings changing nothing then left the mode. I then checked the 2 meter band and all was good. Not sure whether going to that mode resets all to factory initial settings but my radio seems to be fine now! Thanks for all your tips on the ICOM IC706MKIIG! I really appreciate your collection!
Sorry to bother, but I can not find how to adjust the volume of the CW sidetone. The manual has all for CW but not sidetone adjustment.
Thanks in advance for any help.
Look on the right side of the radio (main body), two little holes with trimmers pots inside. Comp Gain and CW Sidetone/Beep level. Instruction Manual page 5 (page 8 of the PDF).
Hi, I have a 706mk2g and when pressing any DSP function such as ANF or NR, this effectively mutes the radio. I am thinking the UT-106 is faulty. Has anyone else experienced this fault?
Thanks in advance
I am having trouble connecting to the MkIIG using CI-V. Tried several cables, computer recognizes the cables but will not connect to the 706. I am suspecting the 706. If I connect a CRO to the CI-V 706 jack any idea what I should see with a CRO?
What is a CRO?
I have no idea; you need to look up the specs for CI-V. I’m guessing it’ll be 0 & 5V serial data, at 9.6 or 19.2 kiloBaud. I don’t know if it generates data all the time, or only when connected to something that talks back.
I have an Icom 706mkiig ku or uk version, I want to expand the tx frequencies in other bands. The typical diode operation is already done like the full reset, however nothing happens. It has a symbol on the serial seal as a bridged diode. Any help is good thank you very much
I have a little problem with the rig Icom 706MKIIG.
Now I am want to program it on FM 2 meters. Now here
what happens I first try to use 146.520 I was
listening on another reciver. So here what happens.
I set the 706MKIIG to 146.520 and I transmit and
on the other reciver. I have to listen on 146.510
to hear myself. Now A couple of hams said that there
is a menu where you can set the transmit off set I look
and cant fine anything. Can anyone help me out with
Bob – wa2aar
Can you check that the RIT isn’t on.
also DUP isnt showing at the top of the screen,
Then ensure “split” isn’t activated.
after that it gets more serious.
Good luck and Happy New Year 73 de Gerald g3sdy
Just lost TX and RX on VHF/UHF.
Any one kwons how to fix this?
I have the 706MK-II-G, for a number of years. I have used it mostly for SSB. Over the last few months I have been wanting to get into digital, mainly FT8. I think that I finally got all of the settings figured out. But to my surprise yesterday, my rig has no RF output whatsoever, any band, in any mode. I hope that it is something simple that I am overlooking. I have checked all of the settings that I can think of. I never smelt anything or heard anything pop.
Use the 13-pin interface jack on the rear panel. Place the rig into Initial Set Mode and move to item #30 (VSEND) and set it to OFF. Now, the 13-pin connector will work for digital soundcard interface on ALL bands! Might require a partial RESET, but NOT a FULL RESET. Worked for me! 73’s,
MyIcom IC-706MKIIG will not key from the rear 1/4″ jack. The full BRK and regular BRK are set, the jack is tip to key, ring to nothing, sleeve to ground. I get no tones or transmit when keying. The microphone jack on the rear doesn’t seem to work as well when I move the stock mic to it.
Anything I should be looking for to remedy this?
Check the Q4 menu to set the keyer mode. Set it to oFF for straight key. See Manual, page 49. If that doesn’t work, it will likely be some blown part and will need servicing.
With the rear microphone jack also not working, I’d first look for corrosion in the jacks. Deoxit D5 is a very good contact cleaner. Corrosion of contacts in jacks can be just a thin layer of oxide that’s not readily visible.
my mk 2 will not come out of memory moe the v/m seems not to have any effect
so the up/down buttons only change the memory icom UK say that because of the age they wont look at it any ideas please
I’d try a factory reset, if that doesn’t do it, take the front panel apart and clean the V/M switch (and all of them while you’re at it) using a safe no-residue contact cleaner.
To see if it’s a software or hardware problem, use a CI-V cable and see if it’ll switch via computer.
My 706MKIIg CI-V seems to be having a problem. I bought a CI-V USB cable and it worked fine until I got a close Lightning Strike. Took out my LAN card on my computer and the CI-V USB cable. Device manager did not see the CI-0V USB cable anymore, so, I ordered another cable. Computer now recognizes the cable but I can not get the radio to connect (using HRD). The Radio works fine otherwise, just no CI-V connect. Any clue where I should look first?
Get the service manual and look at the schematics, start tracing in from the CI-V jack. If lightning surge blew the UART chip in your CI-V interface cable, it likely popped some teeny device in the radio, too. Could be as simple as a trace opened up, or as complex as an SMT IC.
I looked at the schematic and saw no protection for the civ. The IC7000 has an p/n 6910012350 S.BEA MMZ1608Y 102BT inline with the civ and cive. That is what I would add. If you look at the rtty jack it has a p/n HF50ACC322513-B. If I missed it I would cut a trace and add one. The inductor might cause an issue with the signal.
You could also consider the protection the 7000 uses. I had one to open on mine for an unknown reason. I had to remove and replace the civ jack to get to in on mine.
Check this out: https://product.tdk.com/info/en/catalog/datasheets/beads_commercial_signal_mmz1608_en.pdf
Hi William, did you ever figure this out ? My CIV stopped working when I got some RF in the equipment. Locked up my usb ports like it always does. Cable is good. I even tried another but it seems the comms from the computer to the radio are maybe working on one direction. Don’t have a scope here so it’s hard to see what’s going on. Seems in some other forums that D2171 is a common failure.
de Tom, KJ6NA
Is there ANY software that can write memory names via the CI-V interface? I don’t care enough about names to manually mark them with the clumsy method in the manual of writing memory names. I get that kind of garbage from my cheap radios! Icom ought to have provided a means for what these rigs cost new abd still cost on the used market
I don’t think the 706 had that in its CIV command set. Loot at RT Systems software, if there’s a program for the 706 they will have it. Then look at what features it supports.
Remember the 706 was designed in the 90s and has much less in the CIV command set than modern radios.
When I key my mkiig (mobile mount) the bottom of the display changes to a half circle with a vertical line under it. What causes this? It only happens in my mobile. When the radio is in the shack this doesn’t happen. I suspect it’s something about the rf ground but I don’t know… Any ideas?
I’ve never seen that symbol on a 706, and it’s not in the manual. The partial circle & vertical line under it is used on some power & start buttons. Perhaps it means the voltage is pulling too low during transmit. Make sure you have a GOOD clean connection to the battery with #10 wires.
Meu ic 706mk2g aperto botao power o rele bate e desliga, sendo que não liga o equipamento… R591 está bom, sera que pode ser defeito no transistor Q575
I have no idea — this is an English language web site.
Hope you don’t mind me trying to help.
Ensure front facia electrical contacts are clean and that it is connecting properly.
Verifique se os contatos elétricos do painel frontal estão limpos e se estão conectando corretamente
I have noise cancellator unit made from VK5TM page. There is TX pin on this unit that when receive PTT from radio it activates relay and put it in TX state. I do not know how to bring PTT signal to this connector so I can automatic activate noise cancellator (switch it off) when transmitting.
Do you have suggestion how to make it ?
A noise canceller would only be affecting anything in receive, not in transmit. I don’t think you need to worry on it.
My 706 won’t turn on I’ve traced the power around no power exists the pa board no relays kick in no power to the relay on the pa board.it used to come on sometimes now nothing
It’s a rather common problem in the 706. A trace on the underside of the Main board, right near where the board notches around the fan, gets corroded by the adhesive of an anti-vibration pad. Any Icom service tech will know about it. There’s also that little fuse inside. And maybe one of several ribbon cables need to be cleaned and reconnected. There’s a youtube video showing the adhesive pad corrosion problem.
I lover the site man!
I’ve been running my -706 for 15 years+ and its been trouble-free at only 5-10W. I save the power for when it is needed. Anyway……
I do have a question on your “new” -706 set-up. Step 20 (auto rptr) is set to “on2”. However, when I key the mike on 2M FM, there is no observed offset, either in frequency nor displayed frequency. I’ve don’t recall when I last operated 2M FM on this radio, but it’s been many, many years.
Anyway, any ideas on the matter? Thanks & 73s.
It has to be within one of the three repeater freq ranges, then it’ll shift; up 600 for the repeater band above 147, and down 600 for the two repeater bands below 147.
Buenas tardes saludos a todos los colegas , solicito filtro polarizado o protector polarizado para LCD ICOM IC 706MK2G, O UN DISPLAY COMPLETO LCD DCL8309YBGF CUALQUIER INFORMACION SE AGRADECE.
Este es un sitio web en inglés, por favor use el traductor de google aquí. ¡Gracias!
First of all, I really appreciate this site. I’ll throw a couple bucks your way because this is invaluable.
My question might be normal operations, but I was curious as a novice with this 706MkII (not the G). I was transmitting on 10m, with a homemade dipole connected to ANT1, and had a MFJ SWR/Wattmeter hooked up to ANT2, that went on to a VHF/UHF antenna in the attic. While transmitting, I could record the watts from the VHF antenna hookup on ANT2. Shouldn’t it only output from the HF side? I only have one pigtail, so I only have one side hooked up to the meter, the ANT2 side. Curious if that is normal or not. Thanks.
The connection wasn’t secure. Now that it is, it is no longer trying to user the ANT2 output. 😛
Yep, I’m new. 😉
Need help with am , I recently purchased the 706mkiig , everything works fine , I drive a truck a lot for work and I listen to 27.185 often for road reports but I’m noticing that some people sound fine while others sound really gargled up and off frequency , is it them or me, I try using the tuning step to clarify that bad ones in but it doesn’t allow me to go to the far right digits only on ssb .where I can adjust the tuning step all way to the right on a.m. . Any ideas out here
Push the TS button to move the marker over the far right digits. Push and hold the TS button to bring up another decimal place, for really fine tuning in SSB.
Hi, i m Rizal also N2RiZ. i had a problem with my 706 mk2g buy it from Japan Ham fair. when switched on after a while my radio become no audio no signal also no power output. i heard a clicking sound on my radio. when started i can received a signal and power output then sudently it will happened in a few second. please help me
You will need an Icom service tech — or a new radio.
Mine died a few years ago, with 8V relay clicking; I found a used main board online $250, it worked a few months and died again. Ordered a 7100, no more money wasted on the old 706! Parts are too hard to find and too expensive now.
You still have the 706? I’m one of Greg’s Hampsters.
I have a Japanese model MkIIG[M] which is made for the domestic regulations restricting power output on mobile transceivers. The difference between MkIIGM ands MkIIG is only for the 1.9-50mhz range were the M model Tx power range for SSB/CW/RTTY/FM is 2.5-50W , and for AM is 1-20W (vs for the standard G model is 5-100W and 2-40W respectively). For all other frequencies, both models have the same TX power output, and for all functions both models are absolutely identical. There is a modification to remove these power restrictions on the M model – does anyone know how please? Any help much appreciated. Adam
There are 4 tiny pots in the radio that set the max power levels. You need to look in the Service Manual to find them.
Great thanks – I have found these 4 pots in the service manual and I see that 2 of them cover the restricted frequency range – R1082 covers 0-30mhz and R1084 covers 50mhz. Do I turn clockwise or anti clockwise to increase power output to max 100w?? And do I simply turn all the way or must I get some testing control equipment to discover a point that equates to exactly 100W? Many thanks. I feared that surgery would be needed, nothing as simple as just screwdriver adjustment!
You’ll need a magnifier, jeweler’s screwdriver; be very careful, the pots are tiny, use a light touch! Turn clockwise to increase; not all the way, maybe 3/4ths. Connect a good RF meter and a dummy load. Set power at H, mic at 4-5, compression off. Whistle across (not into) the mic (not straight into it). Adjust for ~100 watts. Don’t be tempted to turn wide open, it’ll do ~130 watts but no ALC and probably fry finals sooner or later, mayber put out splatter too.
If that doesn’t do it then there’s something else in the K model limiting the ALC. I donno, you’ll just have to try it and see.
The first item in “intial set mode items” May have been set to not allow AM.
The front panel will work fine. The 432 band will show 132, instead of the 4. I have used the MKII front panel on my MKIIG and all works except the “4”.
I found the same as Paul. I have a MKIIG with the MKII front panel. It has and does everything that the MKIIG does, you just have to use some work-a-rounds.
I have a 706 MKII. I recently started having an issue with the radio not going into AM Mode. I long press the MODE button and it will toggle between FM and WFM, but will not select AM mode at all. I’m as puzzled as can be at this point. Any insights?
It is turned off in setup mode probably! Look it up in the manual!
You have to turn PL tone on (“T” in the display), and set repeater’s freq/offset, and also PL freq, in VFO mode, then store that into a memory channel (MW). Then switch to memory mode, and it should have the right freqs/offset and PL tone when choosing that channel.
Optionally, if the repeater transmits a tone, you can also set tone squelch “T-SQL” on and set it, too, before storing in memory. “T” and “T-SQL” can be same, or different, as needed.
I repair these all the time. Call me I am a ICOM SERVICE Center.
Help – bought a used 706 Mark II G used to listen in while prepping for my Tech?Gen test. I was getting no readable signals but was getting some – Went to a club set of antennas got a readable signal on two freq on 20 and 40 meters (others were to weak t tune). An extra was helping me. Got nothing else on any other bands – Anyway, brought it home – Triple bubble wrapped it and sent it two day USPS to my brother – Came in not damage on box so handling was ok. He set up next to his 706 unit and fired up to test side by side – My radio – no signal – no noise no nothing but lite hiss. He switched both radios and same – his worked my did not – The meter on screen was pegged right. He went through factory reset and then went through the set up menu again – nothing. Any ideas or time to ship to Repair site and hope –
If the meter is pegged right, on receive, either the RF Gain is turned all the way down, or it has a fault in the AGC circuitry.
If you can get strong signals on some bands but not others, the Filter Board may have dirty relays.
I have an Icom706mk11G. It recently started given off an intermittent buzz on transmit. When I speak, I get crackling and feedback over my speaker. I am afraid to send it off for repair as many repair stories are very negative. I have had much success and enjoyment with this radio. The problems with the radio occur when I use the same inverted vee when the radio performed o.k. Bill email@example.com
I donno, never heard of one do that.. Sorry, but it sounds like you’re gonna to send it off.
Is it a external speaker or the speaker on the radio?
icom706mkiig Keyer Paddles: continuous tone instead of dashes?
Has anyone else got this symptom with the icom 706mkiig and an electronic keyer paddle: the internal generator generates dots for the left paddle but a continuous tone for the right paddle (instead of dashes).
I can’t imagine that it’s the paddle or cable … could it be a setting in the 706mkiig? Or is it a defect?
Thanks for any hints!
Go into the Setup menu and find the cw keyer settings; your’s is set to “bug” — it can be set to straight, bug, or paddle (iambic) mode. I forget exactly what the settings are called but you’ll find it in there.
That did the trick, thank you very much! (In quick setting Q4 CW Paddle I now set “n” for normal mode) I somehow misunderstood the manual …
72, Greg HB9GNA
Hello! I have a used 706MKII (not G) that has no CW output but does key and have sidetone. SSB and AM work fine, as does receive. Red front TX light does not come on. I have service manual and some troubleshooting knowledge. Could you possibly point me in the right direction? Rig is from estate sale, dont know history but appears unaltered inside.
Tom Mydosh WA2FWE
It won’t transmit cw unless you turn on Break-In (semi or full). BkIn is on one of the F buttons when in cw mode.
My 706MKIIG has developed an issue. Receive is fine. Transmit audio is horribly modulated, all modes (tried FM, AM, SSB). Both VHF/UHF and HF. Tried 2 mics. Hum/Buzz. RF develops full power on all freqs. Can hear modulation via the mic, just not at all clean.
Before this, the radio had stopped transmitting at all on 2m/70cm but seemed fine on HF. After reading to do a hard reset, I did so and the transmit came back OK, but now the audio was badly modulated – both in HF and VHF/UHF.
Adding a PL tone won’t bring up a repeater.
FWIW, about a year+ ago, I recall smelling a burning component smell during XMIT of the 706. I wasn’t sure it was the 706, but stopped transmitting nonetheless. I believe I was on VHF. Rig seemed to operate OK afterwards.
Opened it up today, examined all the boards. No telltale burned component(s) I could locate. Finals & pre-driver looked OK. Didn’t check bottom of finals / driver board. Filter / relay board looked good, as did CPU board. Radio functions as it should, develops full power on all frequencies. Receive is great. But useless on XMIT all frequencies. Seems like it’s in the audio section. Thoughts?
Tonight, I will check the VCO voltage. I’ve not checked for frequency alignment and I’ve a suspicion it’s off a good bit.
Great news. I didn’t get around to checking VCO, but almost sure that’s the issue. I determined that AM and SSB are OK. It’s FM that’s off frequency anywhere from -15 to +15 KHz. So of course it won’t bring up repeaters and sounds like badly modulated audio. Phew. Went from a condition that looked like blown VHF/UHF finals to the twist of a little trimmer in the span of a day. – N0TM
And the bad modulated audio on SSB and AM – I do think the rig needs tweaking in that respect. I need some better test equipment (or take the rig to a friend’s). But I did determine the DTMF Icom mic has really low and somewhat muddier response compared to the stock HM103 dynamic mic. I haven’t XMIT’ed much with the rig since I picked it up – and I don’t think anyone had the heart to tell me my audio was so bad. We need to be honest about these things! 🙂
My 706 is transmitting 10KHz low when operating FM but the audio sounds fine. What trimmer did you adjust to fix this. I have just started trouble shooting and this could save me much time. I am on HF most of the time but every once in a while I need VHF.
See comment #2 here:
“There is a variable capacitor C1022 which needs to be adjusted until the voltage across the varactor is in a normal range. This sets the free run freq. of the PLL oscillator. The voltage at test point CP 1011 needs to be at 1.8 volts at full power transmit in FM mode on 10 meters.”
There’s a link for the Service Manual there too!
This issue prompted me to get a decent dummy load (MFJ 300w dry for about $50). The manual wants you to adjust while at max power on 29.6MHz (or thereabouts) in FM. I had to adjust the trimmer I think about 1/4 turn to the left.
The 706 has only 1 crystal oscillator (60 MHz) and everything is derived from that by the processor. See my 706 Calibration page.
If it’s off 10kHz on 2 meters, the master osc is WAAAY off, and you need to get that calibrated before messing with the vco or anything else.
Turns out it was just FM, which is what led me to the VCO. Sure enough, following the Service Manual, I adjusted the trimmer about 1/4 turn, which brought the voltage at the appropriate test pad from mere mVs to 1.8v. Voila, FM was back.
So it seems the rig is 100% now. That said, given the age, I’ve set the power across the board to 5, in the interest of preserving the (original design) finals.
My name is Ricky – KM4VAZ and I am located in Kannapolis, NC. One of my hamster friends has an Icom 706 MKII-G which he has owned and operated for years without any flaws. He had it mounted in his vehicle on his dash. Recently it started to lock up after getting warm and he would have to unplug it and plug it back in then it would work fine again for a while then it would lock up again. When I say lock up, I mean the display would freeze, no response from any buttons or switches, could not key up due to no response from the mic, no reception on the speaker. It would just freeze until he removed power and reapplied power then it would work for a little while then do it all over again. Would this be caused by the common fault of the H/V line due to a chemical reaction from the rubber support boots on the bottom of the boards or would this be a sign of an overheating CPU requiring new heatsink compound on the CPU? I work on electronics daily but this one has me stumped. Could you point me in the right direction or explain what may be happening?
Thank you in advance and God Bless.
He is bringing it by my house to be fixed, or hopefully get fixed this weekend. Just trying to get my ducks in a row on this rig before I get it.
The cpu is an 80-pin smt on the bottom of the main board, no heatsink.
That one will likely need a new main-board, they’re occnly used on ebay for ~$250.
and of course you can try n re-seat all the ribbon connectors first…
Thank you, I will try that. Also, I did check for the open circuit on the H/V line under a rubber boot on the PLL board like most people mention and it is open and the rubber feet on the bottom of that board is hard as a rock. I will take care of that open circuit then reseat every ribbon cable. Hopefully, thats all it is. He says he kept it in his vehicle for years on the dash, I told him that is a no no.
Hi. I need help about Idling current adjustment. I have the service manual of the IC706MK2G but it is not so clear for me. I have some doubts about procedures. I measured 1.5 A idling current at tx with Q2 MIC Gain adjusted to 1 minimum at the beggining of the (step 1). I need to increase this current (0.5 A R162 according to the manual) so, at the end of the (step 1) I have an increased of current of 2.0 A. Is this correct?. Can anyone help me ?
That would be one I’d ask an Icom service tech…
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.
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,
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).
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.
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.