© 2003-2015 by Harold Melton, KV5R. All Rights Reserved. Rev.04/26/15
Brand New 706 Setup
The 706 comes with some power-on factory defaults that you will want to change. The recommended changes make the radio easier to operate. First, let’s set up the power-on defaults.
Change Power-On Defaults
Go to Initial Set Mode by power off, hold Lock button and power on. Refer to the initial setup items on pages 50-55.
Item 1 - Mode Select: You can turn off modes that you don’t want the Mode button to select in its rotation: Unless you have an external FSK RTTY system connected, turn off RTTY mode. Most of us on RTTY are now operating AFSK RTTY via a computer, where you’ll be running on SSB.
Items 2-3 - Beeps: When you get tired of hearing it beep, turn beeps off.
Items 4-5 - Backlighting: Set to High for most uses. Set to low for night-time mobile use.
Item 7 - RF/SQL: This requires some explanation! Set to RF/SQL, the knob will act as RF gain from 7-12-O’clock, and Squelch from 12-7-O’clock. Set item 7 to RF/SQL and set the knob to about 12:30 and you’ll never have to mess with it again. If set to Auto, you’ll have to crank it around every time you switch from SSB/CW to FM modes. The “RF/SQL” setting is the most convenient.
Item 8 - Sub-dial: Set it to RIT if you operate HF. This makes the Memory Channel knob operate as a RIT while in VFO-A/B modes. Regardless of where you set this setting, the knob will still operate as Memory Channel while in the MEMOry mode.
Items 9-10 - Optional Filters: Set to “No” if you have not purchased optional filters. If you add one filter, I recommend the FL-232 in slot 1, and set the “Opt. Fil 1” setting to FL-223. This will (1) give you an effective CW filter and (2) let you select “N” (narrow) while on SSB, giving you the 350 Hz filter for digital modes like PSK-31. Installing the 232 CW filter, but selecting 223 (which is an SSB-Narrow filter) fools the radio so you can use it on SSB. See the Section below on Filters.
Item 20 - Auto Repeater: This should definitely be changed from the default. Set it to “On 2” and the 2 meter band will automatically set the right offset when you are in the range of the usual repeater bands — 600 negative below 147, and 600 positive when above 147. This will save you a lot of extra offset-setting while you are programming your repeater channels. Also sets the usual +5.00 MHz offset for 440 repeaters.
Item 24 - AM NB: Set to “off” and the Noise Blanker will be disabled on AM reception, where it will otherwise cause distortion to strong AM signals.
Item 30 - VSend Sel: Set to “off,” the HSend line on the Acc’y jack will key the radio on all bands; Set to “on” (the default), HSend will key the radio on HF/6, while VSend will key it on V/UHF bands. “Off” is useful if you will key the radio from a computer interface for all bands. “On” is useful of you will key the radio with a computer on HF, but with an external TNC for V/UHF. You’ll need to study the book and do some fancy wiring on the 13-pin DIN plug…
Items 34-37 - CI-V settings: Leave the address at 58H; change BAUD to 19200, turn CI-V TRN on, and leave 731 off. To operate with computer control and digital modes, see the interface section later herein, as well as my article on the digital-modes.
The rest of the initial settings are usually OK — by preference, or as-needed.
The Quick-Set Menu
Now power off, and on, and go to the Q menu, by holding in the Display button.
Q1 - Power: Set to HI or as desired. Different power levels can be stored for HF/6 and VHF/UHF RF outputs.
Q2 - Mic Gain: Set it to 4-5, no more. Only one seting for all bands and modes.
- The supplied HM-103 hand mic has very good quality, but never talk flat into it — talk across it, with the side of the mic beside your mouth. The element is too sensitive to use flat against the mouth, and will badly distort.
- If you install a different mike, you’ll need to determine a new “best” mike gain setting. But remember, this is a “pre-pro” Icom, with the high-level (50mV, not 50μV) mic input, designed for an electret mic with a pre-amp. The audio line has 8-volts phantom power on it, and (1) shorting it will blow the 8-volt regulator's tiny fuse (inside), and (2) a dynamic mic (if used) must have an added DC blocking capacitor.
- The mic gain setting is the same for all bands and modes. The setting is not stored by band, mode, or memory channel. Setting the gain at 4-5 and talking across it is sufficient for all bands and modes.
- The speech compressor (CMP) is rarely needed, except in extremely marginal conditions. Don’t use it until you’ve used another receiver (with headphones) and calibrated the compression level. The level is set wih a tiny pot, through a hole in the case, using a tiny screwdriver. It is very sensitive, and will draw complaints if set at more than the ten-o’clock position.
- The output power level is not stored in memories. There is one setting for HF and one for V/UHF. Output power will need to be adjusted manually as you move from nearby to distant repeaters, or from strong to weak SSB stations.
- Icom radios use the ALC circuit to control power output. When you are at high power, you’ll see little or no ALC meter indication; when at low power you will see full ALC indication. This is normal operation. Do NOT adjust the mike gain to set ALC levels, as with most other radios. Leave the mike gain at 4-5, set the power as needed, and don’t worry about the ALC meter, except when running digital modes, where you never want to see any ALC.
The rest of the Q menus vary by mode — see the manual. Most of the defaults are fine, but you’ll need to go to VOX Gain and Delay to set those to your voice, and RPTR TONE (Q6 in FM mode) to set that for each repeater you’ll put in memories. While programming repeaters, you’ll switch between Q6 and M2 a lot! It’s a pain…
Programming Memory Channels
It’s important to set up your memory channels in a table before committing to fully programming the 706. I recommend you:
- Use a Word or Excel table to develop your channel list. Sort it by frequency, then install it. Make columns: Ch#, Freq, Mode, Offset, Tone, and Name.
- Group channels by band; and sort by increasing frequency. This will reduce wear on the filter board relays as you crank the memory channel knob.
- If you don’t have favorites yet, just program a channel every 50kc or so within the ham bands; you can always change them later as you operate (and you will). Also, it doesn’t hurt to leave a blank channel or two between bands.
- Don’t forget to add in some SWL stations, local police/fire/ems, NOAA weather, etc. Remember, it’s not just a ham radio, it’s an AM, SW, and FM broadcast receiver, and V/U public service scanner, too!
- Take your time! The better your list, the less fragmentation will develop over time.
- If you perform the Frequency Expansion modification (below), it will erase ALL settings and memories and return the radio to factory settings. If you REALLY want to use 60 meters and/or MARS, do it NOW and save the long process of programming everything twice.
Programming a Blank Channel
Select a blank channel. On M2, press V/M to select VFO-A. Set the frequency and mode. If this is a simplex frequency, simply press MW to write the memory. Next channel. Repeat.
For duplex (repeater) channels, you also need to:
- Set DUPlex (off/-/+) on the M4 menu (automatically set if AUTO RPTR is set to On 2, see Item 20 above). Watch out for 147.00 repeaters, they can go either way.
- Set TONe (T or TSQL) on the M4 menu (T enables PL tone; TSQL also enables tone squelch)
- Set RPTR TONE (the tone you transmit to key a repeater) on the Q6 menu.
- and if used, set the TONE SQL on Q7 (the tone a repeater might transmit to open your squelch)
…then return to M2 and press MW to write the memory. Done. Go to next channel and repeat until all your list is programmed. Afterward, you can go to G4 and give all the channels descriptive names, if desired. Note that G4 name setting is stored with Exit button, not MW.
To Overwrite an Existing Channel
Simply use the M2 menu: Set to Memory mode, select the channel to overwrite, then change the frequency, mode, Tone, whatever is needed, then press MW to update the channel to the current settings. If needed, also update Q4 name.
All this sounds complicated at first, but after you do a couple of channels you get a rhythm going and it goes pretty fast. Still, it’ll take 2-3 hours to do them all.
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.
Hi. I just recently purchased an older model 706. When I was picking it up from the guy he demonstrated that it transmits on all of the bands. It also has the MARS mod. I brought it home and got set up with an HF antenna 3.5-57 MHz and a vhf/uhf/6M on the same mast. Now it transmits on 2M on memory but not vfo, 10M and 12M but nothing else. Also SWR is over 3. Could the antennas be conflicting with each other? Amy other ideas?
I have an “older” IC 706 that is off frequency on both transmit and receive by 12 KHz.
Anyone know the pot to tweak to zero it back on freq?
Can’t get past step 1. Pages 50-55 of what? My Icom manual? Pg 50 is Troubleshooting, not Initial Steps
I purchased an IC-706 MKIIG from Japan. It works fine on HF, but I found that the two meter band stopped at 145.999. If I turned the dial it jumped to 432.000. I saw a mod on mods.dk to make it operate on the US two meter band. I removed doede D2028 and it now will receive the US TWO meter band, but will not transmit. What can I do?
I bought used Japanese version of IC-706 MK2 S..it is for limited beginner class..HF only 10watt…
1.9-28MHz: 0.5-10W (SSB/CW/RTTY/FM)
50MHz: 1-20W (SSB/CW/RTTY/FM)
144MHz: 2-20W (SSB/CW/RTTY/FM)
Is it ok just to use digital for these radio?
Above link is how to mod it to 100watt..i cant find Feedback transformer L7376
Thanks for this page. It has helped me several times. Not sure I ever bothered to thank you before.
This is a great source to help internalize the 706 MKIIG menu choices.
I have been trying for hours to get my 706MKIIG to transmit VHF digital (VARA FM) from the Signalink. Worked fine on HF, but no transmit on VHF. Menu item 30 VSEND SEL was the key, it had to be set to off.
Item 30 – VSend Sel: Set to “off,” the HSend line on the Acc’y jack will key the radio on all bands; Set to “on” (the default), HSend will key the radio on HF/6, while VSend will key it on V/UHF bands. “Off” is useful if you will key the radio from a computer interface for all bands. “On” is useful of you will key the radio with a computer on HF, but with an external TNC for V/UHF. You’ll need to study the book and do some fancy wiring on the 13-pin DIN plug…
Hi, i had my icom ic 706 mk2 repaired , but i can’t tuning it only at 18 and 21 MHZ (it appears over 3,0 vswr) why?
Excellent lots of information glade I found your site. I have just purchased a IC-706MKIIG and I ask how do I produce a carrier, I have just rebuilt a mobile 160M antenna I have checked it with a frequency analyser all good but I wanted to confirm the results using the radio and a SWR meter. all my past radios have been Kenwoods eg TS-180 TS-50s on these I just selected cw . VK3CXP
Put it in RTTY and key the mic. Or for lower power, AM.
Thank you Harold for the quick reply
Hi again Harold. I have a question about the Icom 706mk2G. I am using a Ameritron 811H, or a Heathkit SB-1000 amp with this rig. Do I need to use a ARB-704 buffer when keying these amps? They both have 12volt keying relays. Another Ham told me not to go directly from the 706 into either of these amps as it wouldn’t key them and would ruin the Icom rig due to the radio having a transistor type of activator instead of a manual relay. Would appreciate your comments on this question when and if you have the chance.
Yes, the 706 uses a low-current SMT transistor (grounded emitter) for the HSEND line. I think it’s 10ma max. The ARB-704 should work, but if you want to save ~60 bucks, use a Crydom solid-state relay. Please see my amp interface article at kv5r.com/ham-radio/2018-projects/amp-interface/. That’s what I used for the 7100 and AL-80B, but it’ll be the same for the 706. Look at the Crydom MPDCD3 (not the DMO063 I used) as it pulls under 10ma on the input.
The Crydom SSR’s are superior to both relays and transistor interfaces because they are optically isolated.
This is Greg Fisher, call WE5GNF. I am here on your site as I just recently acquired a very nice Icom 706MKll rig. I really like the rig. Has very good receive, transmit with the HM-103 mic. Keep in touch if you want. Nice site you have here and very informative. Take care and be safe. 73
Hey Greg, good to see ya! Hope you’re doing well.
FB on the 706; I really liked mine, ’til it developed that power-off problem. I still have it & still need to take out the main board and jumper that place that corrodes under the pad, then run it a long time to see if that fixes it, then sell it. Not often I can sit to the bench anymore.
Haven’t been on the radio in a while.
I have seen two 706s withe the power on/off problem. There is a small rubber pad on the main circuit board. remove the
Pad and u will see where the glue has corroded a trace, causing it to open. You sometimes also find an open choke in that ckt too. I jumped mine out and repaired the trace. Radio has been trouble free for past 10 years now. Good Luck! Great little radio!
I Bought 3 months ago SB-2000 MK2 USB Radio Interface with their cables for icom ic 706 mk2g. i use WSJT-X software. I receive into WSJT-X a lot of Hams using FT8 modulation,but when i activate Enable Tx in WSJT-X my icom ic 706 mk2g turns to tx mode, the power current goes to 4,2Ampers (i transmitt 30 w) , i can see my call sign to https://pskreporter.info/pskmap.html but i can’t make any contact.
Where am i wrong?
I would be gratefull if you help me.
I don’t know, I don’t run FT-8, but if you’re transmitting but not making any contacts, maybe the signal is distorted. Turn your RF power to 100% but reduce the computer audio to get 20-30 watts (and no ALC indication) and the signal should be clean.
Still, if you’re on pskreporter then somebody is copying and spotting you there.
If your compute clock is slow or fast by more than 1 second, you will not be able to decode FT8. Use one of the several time sync apps to sync your computer to a time standard.
Very interesting site, thanks for your effort to gather all this information and offering it to us.
I have an IC-706 MK II (non G) that refuses to TX on 2 meters via the ACC connector. Works fine on HF, not on VHF.
I found that the rig uses pin 3 for HF and pin7 for VHF TX. (HSEND / VSEND) So far, so good. So I tried to connect pin 3 and 7 – but this haven´t had any effect to the issue.
TX on HF ok, no reaction at all on VHF. I´d appreciate any advise !
See the Manual, page 54, Initial Set Mode item “30 VSEND SEL” set it to “on”.
To get into Initial Set Mode, hold LOCK button while turning POWER on. See page 47.
I have an inherited 706MKII that is about 22 years old. I’m about to give up on it for a variety of reasons, but the biggest reason is the 2 meter receive sensitivity. The audio sounds weak, like it’s being heavily filtered. On local nets, some voices are so faint they can hardly be heard, while on another radio they sound fine. S-meter readings for the Icom with the preamp on sitting next to a Yaesu radio listening to the same repeater on the same antenna are maybe 2/3 scale, while the Yaesu is full scale and great audio. Any thoughts? Icom won’t touch the radio, and spending hundreds to fix is off the table.
I’ve heard of a couple of them with poor receive on 2 meters but I don’t know of any common causes for it. You’d need to get the service manual, study the schematics and board layouts; put it on a service bench and trace the signal path. My first guess would be bandpass filter relay but could be many other things. They tend to get PCB corrosion under various vibration pads, and in ribbon cable connectors, too. The bad part is you have to remove boards to get to the undersides, then you can’t power them up and test them without replacing them. It’s very tedious.
hi I have acquired a 706mk2g which I got to wk ft8 seems to wk ok except nothing from abt 8mhz to 15 MHz any idea? tom
8 to 15 is one of the bandpass filters. It could be a filter relay, or the circuit that drives the relay, or even a bad connection of one wire in a ribbon cable going to the filter board. Locate the Service Manual (online, PDF) and look at the schematics and board layouts.
Don’t try to transmit in that range til you get it fixed or you’ll burn up the finals.
I just bought a used IC-706mkIIg, when I’m on 6 meter USB, the receive light stays lit constantly through the whole band, the squelch control doesn’t help. It doesn’t do on FM. Any ideas?
Thanks & great website
Squelch isn’t used on SSB, since the signal strength varies with the modulation. It is only useful on FM, where the signal level is constant.
On 6 meters USB the noise level will be very low and will not trigger the squelch.
New to me IC-706MKIIG
I did your set up and for some reason when I change modes to CW I loose audio. I thought I had CW audio before I did the set up. Is there a setting I did wrong? USB and LSB receive is working normal.
You might have selected a cw filter that isn’t installed.
What a great site. Thank You very much for all the information.
Hi, do i need to hook up both antennas to make my 706mk2g transmit? We were testing a newly acquired unit today and we only hooked up 1 antenna on the 144/430mhz port leaving the hf port blank and we noticed that we couldn’t transmit on 2m. I appreciate your reply.
No, you do not need to connect antenna to HF to use VHF. The radio uses separate finals; 2 for HF-6, 1 for VHF/UHF.
Put a VHF wattmeter and a dummy load on the VHF-UHF port, radio in FM mode, should put out ~50w on 2 meters & ~35w on 440 band, with Power set at max.
If it does not, you’ll likely need service to fix either output bandpass filter relay, or replace the V/U final amp, which may not be available. See next reply below.
I’m new to the 706 world…can anyone answer why my icom 706 when turned off draws 8 amps and gets very hot? Thanks
You have a shorted final transistor. The finals are always on 12V whether the radio is on or off, and a shorted one is the only thing in the radio that would draw that much current.
Before you send it to a service shop, open it up and read what part number the finals are. Early 706s used a part that is no longer available. Then call the service shop and ask them if it’s available.
I recently purchased a 2nd hand IC 706. I have programmed frequencies for HF ham bands,hf aircraft, etc and all works fine. I also programmed 2 meter repeaters and simplex channels as well.I have a 5/8 wave antenna on the roof which works well.Recently all the repeaters and simplex channels seem to have lost sensitivity. 60 over repeaters are now only s9 and s9 repeaters are not even breaking the squelch. I have a 2meter ht with rubber ducky and all the repeater channels have normal signals. Nothing has changed as far as the outdoor antenna is concerned. I have put a 1/4 wave antenna on the back of the 706 with the same results. I am convinced it is the 2 meter section of the 706 as the HF side is fine. Any ideas would be helpful. Thanks for your time………Bill N7CMW
Sorry, I donno. If transmit is good on 2M then it’s not a filter relay. Check attenuator? After that you’ll need to put it on a bench, feed a signal generator in, then trace backwards with a ‘scope and the schematic in the service manual. Maybe the 1st RF amp got zapped. That’s gonna be a surface-mount J-FET or something about the size of a flea…
Thanks for the quick reply.I have always had to activate the preamp on 2 meters to get full sensitivity. As far as the public service bands from 150 megs and up the 706 is deaf. I have always been interested in police, fire and other services in the vhf bands and programmed all of them in and heard nothing.All of my other rigs have no problem receiving public service band. The 706 is a disappoint in that regard. I use the 706 for a bedside receiver with external antennas for HF and one for VHF. I run it on a small regulated power supply as it only draws 1.9 amps max. I emailed Icom tech service and was told although the specs say the 706 receives up to 200 megs it is not guaranteed. I can not even receive the weather service here in Reno on 162.55 and that is a very strong signal. When mobile I only work HF which works fine. Well thanks for the advice I will look into it.
73 Bill N7CMW
I hope this is the right place to ask but i have a IC-706MKIIG and trying to sw between usb and lsb. There are some stations i talked to in hawaii last year but when I looked up the freq it was lsb. any help would be appreciated I have spent many ours trying to get my station set up and running again. grand kids are starting to get interested
Well, it will automatically be in lsb below 10MHz and USB above. To override that, if I remember correctly, you just press and hold the mode button for 1 second to switch lsb/usb. Or that might be how to switch filters. Anyway, pressing the mode button rotates through the modes, but if you don’t see a mode in the rotation, check in setup menu where modes can be enabled/disabled. See Initial Set Mode, Item 1, above.
The 706MkIIG manual is available on-line as PDF, just search for it.
Icom IC706MK11G .The rit/sub switch seems to be glowing orange will not go RED or GREEN as stated in the manual
as this was recenlty purchached second hand .Ihave done afull reset and tried everything posible maybe I am missing something .Mch control just changes memory channel number
I think it will only go into RIT/Sub mode if you are in Split mode in SSB or CW, not in VHF-FM. I don’t remember as I never used split or RIT. Could be the button switch needs cleaning, too.
Looks like it is the swich gone intermitent it came green today and afer constant pressing on/off it went off .What do you recommend for cleaning a spray wth contact cleaner from the front
Caig DeoxIT D5. It’s the best. But watch out, it sprays out way too much and makes a mess, so spray some on a q-tip and squeeze a drop around the button.
If that doesn’t get any in the switch, you’ll have to disassemble it. I’ve never had to open mine; perhaps search for a video where someone has. It might be little mechanical PCB button switch, or a bubble membrane, I just don’t know. I’ve only done switches like this video.
Any idea why 706mk II shuts down and turns right back on when keying the mic on 53mghz channels?
Most likely idea is you’re getting too much RF on separation cable? Poor power supply connection or grounding?
Hi, I dont know if you can help, I bought a 2nd hand 706Mk11G, if I tune below 145.500 (S20 or the calling channel here) the rig puts in a tone and repeater offset, how can I remove this? tuning above S20 does not add the tone or shift.
go in setup menu and turn off Auto Repeater
Hello, I have an ICOM 706MK IIG wanting to use the SignaLink USB Sound Card. Power is via USB Port 3 from Toshiba Lap Top. Radio interface is via rear 6-pin mini DIN jack. Having difficulty with CW. Not sure if using rear external speaker port of radio to USB sound card is the correct method to establish better receiving of CW? Any suggestions would be helpful.
One of the lines in the 13-pin acc jack is audio out. I don’t know about the mini-din jack, never used it.
For keying, you have to use the 1/4″ key jack, set in straight-key mode, interfaced to computer serial port (or USB to serial adapter), with a NPN transistor in a simple grounded emitter circuit.
I have a question on my IC-706, when transmit, SWR meter does not work.
How to check in set mode adjustment,is everything OK. Greeting Dule YT1Q
First off, What a great website! Thank you for taking the time and effort to post such a vast wealth of knowledge. Kudos!
I have an original model IC-706, not Mkll or Mkll/G, and the VFO encoder is broken and not even in the radio.
My question is this: can the CI-V cable and my computer still control my radio without the VFO encoder physically installed (I am awaiting the arrival of a new encoder from ICOM UK)? ICOM USA would not sell me the encoder as they have reserved all their remaining stock for “internal use only,” and my radio is “too old to repair and I should just buy a new radio”… according to ICOM USA in Washington! ?? I’ve tried using HRD and BKT but have had no luck with either of these programs.
Do u managed to solve your VFO Encoder?It just happen to me..so u know any replacement for it?I am upset.now.
I just purchased an ICOM IC-706MKII without a separation cable. But I have one for my ICOM IC-703. Will it work on the 706?
Found out that yes the separation cable for the ICOM IC-706 is the same one used on the IC-703.
I have a question on my IC-706mkIIg. It transmits full power on UHF (20) and VHF (50) and is adjusted using the main dial from L to H with numbers 1 – 9 in between. NOW, on HF using the main dial to adjust the power it seems the power peeks at 100 watts on the number 5. Numbers 6,7,8,and 9 and H there is no change. I figure there is an internal adjustment to make 100 watts while on H and reduce power as the numbers decrease. Can you let me know exactly where this internal adjustment is?? I apologize if this is not posted in the correct area.
THANKS, 73, Mark N2FLF
There are 4 tiny pots that set the max power in various bands. You need the IC-706MKIIG Service Manual (that’s a BIG pdf, wait for it, then save it). See pages 4-2, 4-3. You’ll probably find that someone has cranked R1082 wide open.
If not that, something may be wrong with the ALC circuit, which controls the power output, and it’d need bench repair and alignment.
I recently bought a used 706MKIIG. I now have an issue only getting about 7.5 watts on HF (low power on ALL modes, ALL HF bands) and low power on 2M and 70cm. I did a master reset but no luck. Then I tried looking for the issue by putting in RTTY mode and poking at any connection inside the rig, but after about 2 minutes of transmitting for about 2 seconds while prodding at connections, the radio shut off and took like 20 minutes before it turned back on, just now I went to double check if it had any power out on 2 and 440, now it will not turn on at all! I am so scared and sad (now shaking)!
Please help, point me in a area to check if ya can!
Since you just got the radio, I’ll ask an obvious, did you go into the Q menu and check what the power is set to? I can see why it would be low on HF (bad load, bad SWR detector, bad relay on filter board), but VHF/UHF uses a completely different output final (with no swr checking). So if your power is set properly in Q menu in both HF and VHF you should get ~100w on HF and 50 on VHF (and 20 on UHF).
As for going completely dead, the only thing you can check is the main fuses, and the tiny internal 8V fuse, you might have blown that or even the 8V regulator. The 8V system is what powers all the computer chips including the main processor.
Note that when “off” it’s really in a “sleep” mode — still has 12V on the drivers and finals, and 8V on the processor. The “power” button actually grounds a pin on the processor, which then sends a signal to a tiny SMT transistor, which pulls in a little relay in the 8V subsystem, which wakes everything else up, thus turning the radio “on.”
Beyond that 8V internal fuse, about the only thing you can check inside is make sure all the little ribbon cables that interconnect the boards are seated properly (you need to look up a video on how to open and lock those little ribbon connectors or you’ll ruin them if not done properly and carefully).
Don’t poke at things in modern SMT electronics, in my experience that always makes things worse! And make sure you disconnect the power jack before doing anything inside — remember “off” isn’t really off.
Great writeup for a 706MkIIG newbie like me. Thanks for putting in the time and energy!