Yeasu FT-767GX Mod Mystry

[743]

Hello all,

I thought I would run this one by the experts. I acquired a mint condition Yeasu FT-767GX with CAT system. I performed the mod to convert it to all band receive and XMIT. The mod requires a complete disassembly of the radio just to get to switch S01, a slide switch, and move it to the next position. This switch has only two positions so doing the mod was easy. Once done the mod says it will xmit from 1.5 to 30 MHZ which is just what I need for 27.385 lower side band. Post mod found the internal tuner does its job like it should but no output on any CB frequency. Trying the Ham band frequencies the radio puts out about 130 Watts USB and LSB. Thinking the mod had been done before I got it, I took the radio apart again and returned the switch to the original position. Results were the same. Worked great on the ham bands but not on any CB channels.

What am I missing here? Mods from different sources read the same. "Flip the switch marked So1". Any help from the experts would be most appreciated in solving this mystery.

Thanks to all. 743 in Phoenix

[MDYoungblood]

I would say that the ham operator that you got the radio from knew you were planning to flip the switch and disconnected it, check that out first. Once you open the radio back up with the knobs toward you looking down into the radio the switch should be in the position to the back of the radio, that is the "General Coverage" position.

FT-767GX
#1.
Remove the bottom covers,plastic rear panel then the metal rear panel,loosen the hinge screws on the front bottom.
Lift the loose card tray to expose the inner circuit boards,there are two wires that need to be disconnected to do this (dont forget to reconnect them!).
The board we want has some switches on it,(one of them allows 5 Khz/rev or 10 Khz/rev tuning), locate S 01 and flip the switch.
The radio can now transmit from 1.5 Mhz to 29.999 Mhz
#2.
Switch off the tranceiver and remove the AC power cable and all other cables from the rear panel.
Remove the two screws affixing each VHF or UHF band module and slide the modules out of the tranceiver.
Remove the two screws at the front of the top cover (heatsink).
Place the tranceiver upside down and remove the four screws from the bottom corners and two on either side (including the carrying handle screws). Remove the carrying handle and bottom cover.
Remove the seven black painted screws from the rear panel. Then remove the black outer rear panel.
Remove the ten screws from the inner rear panel and remove this panel.
Remove one screw on either side (rear).
Locate the white molex connectors (one for power and one for the speaker) inside the rear of the chassis and disconnect them.
Fold the lower half of the chassis away from the upper half, placing a book of about the same thickness of the heatsink under the bottom half.
Locate the "LOCAL UNIT" board under the metal shield. At this board, locate switch S01 and change its position. The rig will now transmit from 1.5 to 30 MHz.
Reverse the disassembly procedure

I am guessing these are the mods you looked at. There are others but they all say the same thing.

3's

Greg

[Bluerunner]

I had to re-program my Yaesu 747 by holding down certain buttons when I turned it on to let the mod work.

After that it remembers. Don't have to do it every time.

[743]

Thank you Greg and Bluerunner for this very interesting feed back. I can see I overlooked one important step and that was to see if that S01 switch actually works. I saw no evidence of tampering but the previous owner would have disguised any effort to avoid leaving signs of tampering. I will get back inside the radio for the 3rd time and try again. It is a very tight squeeze to get to S01 and maybe, if there is room, solder the connection if nothing else is attached.

Mr. Bluerunner, it would help to know which buttons need to be pressed while turning on the radio. This post conversion step is not mentioned in any of the conversion literature but I have ham radios that did require this effort. In fact I have too many radios I have converted without a hitch. The FT-767GX has the finest SSB reception of all the radios I have. Next in line would be my Yeasu FT-840 for reception quality plus it was the easiest conversion I've done. Just remove the top cover, ground a test point and move the frequency control while observing what the display says. One rotates the tune knob until the display reads what the conversion step is supposed read. Remove the grounded lead and you are done!. Total time was about 10 minutes total. I was amazed.

One thing different I will try this time is to leave the "Keep Alive" battery in the on position instead of turning it off. I will advise the results later today. Choosing a good radio to drive my Swan MK II which I'm restoring from the ground up is the goal and either radio meets my requirements but the FT 767GX so far outshines all my other radios. I have a Kenwood TS-130S, a Kenwood TS-430S, a Yeasu FT-840 and the Ft-747GX. At some point these radios will show up at favorite store that gets me in trouble if I mention it though it does contain the letters BAY. Thanks again to you all and enjoy your Sunday.

Cheers, 743

[Bluerunner]

This is the programming mod on the 747 after the hardware is modded.

Turn radio on and set display for 12.345.6 and then turn radio off and then back on.

Been a while since I did it. Don't know if it will help you.

[743]

Thanks, I'm still putting the radio back together. The absolute worst wiring I have ever seen. Maybe this will do the job and it will work but the wiring is soooo bad that it may not even turn on.

-- September 10th, 2014, 11:27 am --

Hello fellow participants. I would like to thank all of you who gave it a go in trying to resolve the problem with my Yeasu FT-767GX. Nothing seems to work. To verify the integrity of the conversion switch So1 would require a complete removal of the circuit board for the "Local Unit" which has too many wires attached plus add to that a heavy and bulky radio that looks like it was designed by a group of Monkeys that ate too many rotten Bananas (alcohol). Wires are routed all over the place. I gave it a dose of DetoxIt which is the best I could do.

Although the 757GX has the best receive on SSB, my Yeasu FT-840 and Kenwood TS-430S follow close enough behind to power the Swan MK II linear (when it's done, maybe a couple years from now). I will try to get hold of someone at Yeasu to see if they want to get involved. Maybe they would give the radio a major tune up and fix whatever needs fixed. Probably a very expensive way to go, and there is also the possibility of selling it but I wouldn't feel wright trying to sell something that isn't up to spec.

The antenna tuner works well and listening to it as the frequency is changed is kind of neat. In the mean time, if anything new shows up I'll ley you know.

Cheers and 733s from 743

[MDYoungblood]

I am sorry to hear it didn't work, just one question, are you trying 11m into a dummyload or an antenna through a tuner, some radios won't key if there is a mismatch. Saying the wiring is a jumbled up mess has me to believe someone has tried before and failed. If you need a manual for the radio you can get it here , http://www.rigpix.com/yaesu/f ... manual.pdf .

3's

Greg

[743]

Hello Mr. Youngblood,

Yes, this was done using my DOSY and MFJ Dummy load. On 27.385 LSB there was no measureable output. Not even on AM. I then started from 160 MTRs trying all the ham bands. The radio now begins to work but the power out is less than when I started. Where SSB is permitted SSB would work as would AM. On all bands the AM output measured about 50 Watts except for 40 Mtrs which measured 100 Watts! The readings indicated on my DOSY agreed with the readings on the FT-757 which has a window where you can see your power out or SWR but the rest if the display is blanked out. I think I'm tired of messing with it and will list it as for parts and get rid of it at auction. It looked good, price was high but I lost out. Wouldn't be the 1st time. I think we can put this to rest. Oh, no CW readings were taken as the unit has an internal iambic code generator that requires a stereo type plug for use with paddles. It came with a 2 meter module installed which was not tried.

I'm done and thanks for all your help. 3s from 743, The Old Desert Rat in Phoenix.

[MDYoungblood]

Yep is sounds like it's all whacked up, who knows if the main board is hooked up right or what pots have been turned.

3's

Greg