What a great joy to watch so nicely done and challenging I can't express my deep appreciation to showing me this. I own a 706MKIIG and glad to see the inside of it and learn so much that would be valuable to me if it ever needs repair. You really do the best work, and show the details most leave out which is so helpful. Great repair well worth watching. super thanks till next video
Great video...can't believe I watched the whole thing, though. My friends would tell me to get a life. But, as a ham operator since age eleven (63 now), and having built my first receiver back then (winding my coils around old tube bases), I found your video very entertaining. And, I love my 706MKIIG. Good job, good narration, and great camera work!
G'day Peter, many thanks for an awesome video. It make you think of the parts we have in our radios and why it burn out. One person gave up and the next bloke repaired it. Thank goodness we have people like Peter.....I am very impressed . Cheers mate.
Dennis Peake Hi Dennis, thanks for the nice feed-back. I'm glad that you like my vids. Well electronic components fail and very often we do not really know way but silicon components age and this is a matter of fact what is not very much known...all the best mate!
Great repair job on a otherwise dead radio. Not many would tackle that kind of board damage. I work in the 2-way profession and generally that kind of repair is not done. On my own time I have done similar repairs. I like your shop / work bench, plenty of top notch test equipment. I would feel right at home. Just found your CZcams channel. Keep up the great work and videos - I learn a lot on multi-band radios from you.
Thank you for your videos. I love the way you explain when you show us the schematics, and even a dummy like me can follow you and learn how to read a schematic. Thank you for taking your time to show us this. 73 from LB5JG Norway
Like the video, well done, l have been out of Ham Radio for almost 10 years and all l have now is my lcon 706MK2G and when l put it away was working fine, looking to power it up and spend so time with over the winter. Once more nice video.
Great video and radio. Only problem I've had is VERY intermittent receive being very weak on 2 meter ssb. I think it might also happen on fm, but it's been a long time since I've used this radio on 2 meter fm so I don't remember. It's never been frequent enough to warrant taking it apart and quickly goes away when you quickly key the mike a couple of times. I love the vfd display on the LP-100A. Looks like a nice piece of test equipment. Best regards.
+Mr Carlson's Lab thats why an icom fan i can buy them up cheap and repair and upgrade . i picked up an ic910h and a 756pro2 both with this same issue . and a 746 with an inop display
Yet another very good and interesting video. Always worth an attempt at a repair, keep the repair videos coming. Always fantastic to watch you working.. Karl.
Pasquale IW0HEX Hi Pasquale, yeah it seems that this type is now coming into the age where the failing rate is increasing.. Thanks for comment. 73s Peter
Coming to this very late in the day! However an excellent description showing how to replace the burnt out pre-driver driver FET Q121 in the the 706mk 2 g. It would have helped me if I'd seen this before same fault occured in my 706 (s/n 16566) after many years of good service I inadvertantly left it on TX for half an hour it failed. After replacing the FET the fault occured again but only after a short period of TX (Q121's relies on the PCB as a heat sink which it seems is less effective if the PCB is burnt) . The problem appears to be due to R122 in the gate bias circuit of Q121 being factory fitted with a 4.7k resistor instead of the correct value as shown in the circuit diagram & parts list as 2.2k . This sets the bias at about 4v instead of 2v. Q121 then draws too much current eventully fails out if left on TX for too long. Other 706 owners have it seems had the same fault. Were only706's from a batch affected or does it apply to all Mk2g's ? I believe that some 703's may have had a similar fault. 73... Ken G3LVP
Grant Fullen Hi Grant, yes that is true it is always a risk to do repairs like this due to guarantee claims but anyway I find it worth to repair. Thanks for comment.
I know a bit late but tnx a lot! I have now exactly the same issue iand it just helped me to trust in my own abilities to understand to circuit. Since then MXR9745T1 became obsolete and ICOM doesnt stock them. For those who need - any small signal N Channel FET, including BIG rd15hvf1 will work but I used original (china) and tested also 2SK with SO-69 package and modified the bias / gain circuitry. Again, tnx a lot 73! OK2IT
Peter another fine mess you sorted out the worse thing when someone else has been inside and left a mess for you to repair people would be better to bring them to you to fix instead of trying to fix as they could do more damage and give you extra problems to sort out well done to see an expert at work :)
I tend to remove all scorched pcb material (and then fill up with epoxy to get flush), especially when its near FETs, as the material often comes down to a few MΩ per square or even lower, and the FETs gates often don't like that at all.
Very nice repair Peter- that board was just about a write off! Nice radio though. Yeah I saw that 5.6k on the schematic too and I thought it looked odd! :D
Wow, Peter, another great video. I cannot imagine you would work on a radio that someone else has butchered. I sure do enjoy your videos--you are a top notch technician and teacher/instructor. Were you aware of the "new" heat sync paste that is available now? It has some kinda metal made into the paste which is supposed to conduct heat much better than the white paste. I just heard about it from another Ham. Cheers & 73 from W Rusty Lane K9POW in eastern Tennessee
Peter , I was hoping to get more info on glueing the copper trace back ? I have looking around to see what others are doing to glue back old , or put in replacement traces ? Thanks for your efforts . John
KD0CAC Hi John, well that is not so complicated. In this case it was enough copper left, so I cleaned the pat that we can solder again on it. Then solder the component first and then put a drop super glue to the pad that's it. If the damage is bigger you take copper foil cut it out like you need it and glue it on the board. Carefully do the through connections and after that put the new component on.. Hope that helps a bit.. Thanks for comment 73 Peter
This problem ive seen before..i burnt out on of my 706's just like this one but with more severe damage than meant the board was not repairable..burnt boards are sometimes resistive, carbon conducts and worse at RF , so even if the track is at the correct resistance to ground via resistors, it could have serious problems at RF frequencies. one has to ask why the pre driver gets so hot that it burns its tracks and fails in the first place.. ive had 5, 706's and they are great radios, cooling is a major issue, the internal fan mod, that we did even on new radios was to add a resistor to the switchable fan supply ( that increases cooling during transmit ) direct to the 12v supply (13.8v) so that the fan runs a little faster all the time and keeps the radio cooler. I even did a 2nd upgrade to my current radio last year during a heatwave as shack temperatures were so high i decided to increase the air flow.. by reducing the resistor value further to increase fan speed.. this mod is recommended for many small high power radios where cooling is critical. I've repaired boards by inserting a new section having cut out the burnt section and making a copy section from another board , de populated to be able to photocopy and etch a replacement section. not an easy task but its been done with success. having a good section of PCB under the components is necessary to assure sufficient cooling and heat dissipation after the repair. Thicker copper plated boards are better for heat transfer and rebuilding burnt tracks with better boards is recommended. good repair..
I enjoy all of your videos, I wish I had some of the equipment on your very well stocked bench! I see you have a rubidium standard on your bench, do you also utilize a GPS locked reference as well? All the best from KC2IRV
Hi Peter...I think its Peter, most interesting video and good to see you get the radio working. I've just done similar repairs but my damage was much worse!....L232 supplies 13.7 Volts to the VHF/UHF Power FET because this draws 12 Amps at full power it gets pretty hot...its taken over 10 years but just last week this connection into the PCB was slowly breaking down to finally result in a small electrical fire that created a 6 mm hole right through the PCB!....I had to use Solder Wick Braid to replace damage tracks, I've only just placed power on and all seems okay albeit the power appears a little low on VHF. I lost a small ceramic SMT capacitor that sits just under L232 between ground and the Drain of Q231 but its not shown on the parts layout diagram on page 59 of the Service Manual. In your video I could see the capacitor was fitted, I wonder if you might have information that indicates what its value is and or its circuit reference?....CheersClint - VK3CSJMelbourne
I was looking for specific info , I've been in a lot of trades and can put together lots of things , so I was not looking for general glueing something together . Specifically traces / pads on circuit boards , finding adhesives meant for that purpose , heat resistive extra .
The most common reason for Q121 to blow out is that R122 was often stuffed with a 4.7k resistor instead of 2.2k, which forces the VGS of Q121 to about 4 VOLTS all the time! That makes it dissipate almost 2 watts continuously. The fix is to either pull the board out and change R122 to 2.2k, or, to simply add a 4.7k resistor from the gate of Q121 to ground, which brings the bias down to around 2 volts, and the idle power down to under 200mW. Lowering the power via the menu on the radio will not change the idle power! You can measure the Vg to ground on Q121 to see if your radio has the issue. If you read around 4V, you need to fix it ASAP. So many IC-706MKIIG are just about to fail due to this error. I will post a video shortly on the details, but the fix is simple and can be done by anyone with a little soldering experience. 73 and great video! de W6EL
I have a question about the 706. I have found that every couple of years of operating in the mobile environment, I have to clean/polish the contact area between the metal case and the leaf-spring grounding strips. Do you recommend leaving these contact areas "dry", or using some type of conductive grease?
Hi Alan, yes that is a known issue with the 706. After cleaning I put a very thin layer lubricating oil onto it. www.ballistol.de/90-1-BALLISTOL-Universal-Oil.html This is originally a weapons oil but it is a kind of insider tipp as it works excellent for electronics like potentiometers and switches and everything...Don't know if you can get it but I'm sure you have something similar.. 73
Usually the operation on certain bands start to get erratic - things like TX power varies or won't go to full power, RX sensitivity varies, and in general these things will very/change with vibration, even from slapping the body of the rig. For me, 17m and 40m TX power variation is the first thing I see.
Hi Paul I have a AOR AR 8200 WIDE RANGE RECEIVER bought the apparently has an error with the S-meter. The S-meter has permanent full scale. The receiver has been disassembled ever to renew the backlight. Did you ever feel like to look over? Perhaps it would be an interesting video on your channel. Lg Jogi from Cologne
hi hope ypour still repairing radios sir i have the old 706mk1 i was useing it on 20 watts when hi keyed up to respond to a call i heard a iss from speaker then sudden problem on receiv on hf 20m everythink works normal just no receive 2m band works with signal as normal thanks im in the uk thankyou
Superb video Mr TRX, I love watching you work as you have lots of patience and dont seem to ever let a problem beat you - Just one question for you and this is when peaking out the transmit on a transmitter do you think an analog meter is easier than you're digital one sometimes? I always prefer analog for peaking as a digital power meter I find a little jumpy! But I suppose its a personal choice? Anyway very interesting videos you make and keep up the great work my friend.......All the best from the U.K......
+gripper021164 Hi, thanks for the nice feed back! Yes I totally agree with you, an analogue meter is for alignments much better. Therefore I use my big Philips meter for RX tunings and my R&S Level meter for hf tunings. In this video it was not a precise alignment it was rather more a approximate 100W adjustment and therefore the digital meter is okay. Again thanks for stopping by!
Hello TRX bench. I have a Mk2G which became intermittent in both TX and RX. Since about a week now both RX and TX now gone. Looks like a fault in some common line. Can you give me a lead on what could be possible trouble points. Thanks. Rahul.
Hello , I have same this txrx hf not transmitted and receive but the v/UHF working well , I try to open top cover to see is there burn think , nothing found , but I press PTT on HF the fan is worked , due to no work shop in my country how can you help me ? 73
Greetings dear friend. Could you help me to be in the SET MODE ADJUSTMENT of the Icom IC-706 MKIIG? I don't know the type and configuration of the Plug that is connected to the REMOTE to access its Service Menu.
Good outcome on a job that many technicians would probably not touch. Burnt PCB, dubious components, evaporated traces. Not a good start! My question would be why that pre-driver FET suddenly went short circuit. Your guess that the 5.6 R was incorrectly labelled was a good one, and if that source resistor had been 5.6k the maximum current through the resistor would have been 2 mA but as it is 5.6R, the current is over 2 amps and power dissipated in the resistor would be almost 30 watts, no wonder things got (too) hot! 73 Andrew VK1DA.
You got some patience dude. . . One look at that and it would have gone in the trash can if it was me.... Feels good to rescue such a dud though, I have done it, and it feels good.
Peter I have mk2g that has stopped both to and rx. VHF uhf seems fine. Very poor sensitivity on hf. Only very strong broadcast signals come through. Obviously some parts that are common to tx/rx have gone bad. How do I start troubleshooting ? Before this happened both the tx and rx became intermittent. Thanks. Vu2yk.
Ham Radio DK2NDR Hi Andreas, sorry für die späte Rückmeldung, gerade aus dem Urlaub zurück... Danke für Deinen Kommentar, freut mich das dir mein Video gefällt... beste 73
Hola buenos días, soy Felipe padilla HJ6GPJ -Colombia. Tengo un radio icom IC 706 MKIIG malo. No enciende. Alguna forma de reparlo o un manual de fallas o reparaciones. Muchas gracias Felipe padilla Jaramillo HJ 6 GPJ
hello, do you know why the icom 706 gone deaf in the vhf part, I tried to check all parts and seen to be fine but the manual does not say where to find the vhf troubles. if you know or have a clue I appreciated any info that you could give me. Best Regards jorge
+jorge marban Hi Jorge, no I had another fault in mind. The radio needs to be on the bench for investigation. Sorry can't help you from the distance. 73
Sir good evening. I am vu2nsk whenever I have time I am watching your video. Now I have one vertex vx7 R .I was put in charge long time the charger was heated and qrt. After I switched on the vx7R nothing happened . I hope it was QRT. SO please let me know what is the problem. Can you give some idea. If I send it to you can you rectify it sir. In India no service person is available.please reply
I wish you had cleared away the charred area of the board before installing the new transistor. The previous person looks to have been defeated by the situation and abandoned it to your care.
As an Icom ic-706 mk2G owner Your vido was probably the most interesting I have watched for a long time. Thank you.
+Robert Scratchet Hi Robert, thanks for watching, I'm glad that you like it, All the best and 73
What a great joy to watch so nicely done and challenging I can't express my deep appreciation to showing me this. I own a 706MKIIG and glad to see the inside of it and learn so much that would be valuable to me if it ever needs repair. You really do the best work, and show the details most leave out which is so helpful. Great repair well worth watching. super thanks till next video
Great video...can't believe I watched the whole thing, though. My friends would tell me to get a life. But, as a ham operator since age eleven (63 now), and having built my first receiver back then (winding my coils around old tube bases), I found your video very entertaining. And, I love my 706MKIIG. Good job, good narration, and great camera work!
Another great repair. I love to see radios like this being brought back to life instead of being scrapped.
technos123 Hi, thanks for Feed-back. All the best mate. 73's
technos123 hi, yes you are Right. Would be a shame Idee Radios like this are for the trash. Thanks mate 73
@@TRXLab you are a GREAT ! you an ham-radio collegue ? if yes your call ? thans for your great video !
G'day Peter, many thanks for an awesome video. It make you think of the parts we have in our radios and why it burn out. One person gave up and the next bloke repaired it. Thank goodness we have people like Peter.....I am very impressed . Cheers mate.
Dennis Peake Hi Dennis, thanks for the nice feed-back. I'm glad that you like my vids. Well electronic components fail and very often we do not really know way but silicon components age and this is a matter of fact what is not very much known...all the best mate!
Peter Good to see an electronic engineer at work it is a joy and thank you!
Thank you John!
Excellent diagnosis and work ! I love watching your videos they are relaxing in a way.
Great repair job on a otherwise dead radio. Not many would tackle that kind of board damage. I work in the 2-way profession and generally that kind of repair is not done. On my own time I have done similar repairs. I like your shop / work bench, plenty of top notch test equipment. I would feel right at home. Just found your CZcams channel. Keep up the great work and videos - I learn a lot on multi-band radios from you.
Thank you Robert and welcome to my channel mate! Have a great time 73
Another excellent video! I thought it was toast when I saw the burnt PCB, great job saving this radio!
Thank you Steve! 73
Another great video Peter. Thanks for posting these.
Impressive repair, you are very brave to take on someone else incomplete work.
Great video, Thank You!
knunne1 hi, well yes sometimes it is a night mare. Thanks vor comment 73
Thank you for your videos. I love the way you explain when you show us the schematics, and even a dummy like me can follow you and learn how to read a schematic. Thank you for taking your time to show us this. 73 from LB5JG Norway
Glad that you liked it! Thank you
Like the video, well done, l have been out of Ham Radio for almost 10 years and all l have now is my lcon 706MK2G and when l put it away was working fine, looking to power it up and spend so time with over the winter. Once more nice video.
Thanks for feed-back Lionel. Yeah the 706 is still a nice radio so have fun over the winter 73
Great video and radio. Only problem I've had is VERY intermittent receive being very weak on 2 meter ssb. I think it might also happen on fm, but it's been a long time since I've used this radio on 2 meter fm so I don't remember. It's never been frequent enough to warrant taking it apart and quickly goes away when you quickly key the mike a couple of times. I love the vfd display on the LP-100A. Looks like a nice piece of test equipment. Best regards.
Great repair again Peter.. It was good to see that it wasn't a 3 or 4 layer board, or this could have been ready for the trash.
Regards my friend
John
***** Hi John, thanks a lot! Yeah glad that I was able to rescue the radio...best regards my friend!!
I Missed the notification, I'm Late! Great Video Peter! Hey you know what ICOM stands for, I Can Only Monitor. LOL! Thanks for the kind mention.
Mr Carlson's Lab Hi Paul, thank you! Yeah ICOM and not even a monitor HaHa.. Take care my friend..
+Mr Carlson's Lab thats why an icom fan i can buy them up cheap and repair and upgrade . i picked up an ic910h and a 756pro2 both with this same issue . and a 746 with an inop display
amazing Peter. I had doubt but again you pulled it off. Thank you for the video
Another great presentation of the art,thank you Peter for your very informative videos.
Chrysiotis Thank you mate :-)
Hi Peter, that looked a real challenge, you managed to do it, great video and repair...Fred in UK.
Tom Smith Hi Fred, thanks a lot!!
Very precise and careful, with attention to detail, thankyou for the excellent video.
Yet another very good and interesting video. Always worth an attempt at a repair, keep the repair videos coming. Always fantastic to watch you working.. Karl.
Karl Fell Hi Karl, thanks yes there are more vids to come. 73
I just started watching your videos, your wealth of knowledge is amazing. Your videos are informing. thank you.
Glad that you like my videos...Thanks for watching 73
Well done ! I learned some things from your video .THANK YOU 73 Bob Michigan USA
Thank you very much for fed back Robert! All the best 73
I repaired an ICOM 706 MK II G with the same fault and I had driver fault also, very hard to solder it !!!! Thanks Peter. 73s Pasquale IW0HEX
Pasquale IW0HEX Hi Pasquale, yeah it seems that this type is now coming into the age where the failing rate is increasing.. Thanks for comment. 73s Peter
Great repair - really enjoyed following along.
Cheers, John
+Zone1242 Hi John, thanks for stopping by and comment. !
Very I really enjoyed and benefited from the step-by-step description of your troubleshooting technique. 73 de NT5A
+Robert Ahrens Hi Robert, I'm glad that the video is of any need for you! Thanks for comment 73
Coming to this very late in the day! However an excellent description showing how to replace the burnt out pre-driver driver FET Q121 in the the 706mk 2 g. It would have helped me if I'd seen this before same fault occured in my 706 (s/n 16566) after many years of good service I inadvertantly left it on TX for half an hour it failed. After replacing the FET the fault occured again but only after a short period of TX (Q121's relies on the PCB as a heat sink which it seems is less effective if the PCB is burnt) . The problem appears to be due to R122 in the gate bias circuit of Q121 being factory fitted with a 4.7k resistor instead of the correct value as shown in the circuit diagram & parts list as 2.2k . This sets the bias at about 4v instead of 2v. Q121 then draws too much current eventully fails out if left on TX for too long. Other 706 owners have it seems had the same fault. Were only706's from a batch affected or does it apply to all Mk2g's ? I believe that some 703's may have had a similar fault.
73...
Ken
G3LVP
GOOD JOB.
Some shops might not try that , but I think it is a good repair and it may last :)
Thanks for making and sharing these videos.
Grant Fullen Hi Grant, yes that is true it is always a risk to do repairs like this due to guarantee claims but anyway I find it worth to repair. Thanks for comment.
Great repair job! Thanks for all your videos!
+Beretta96Dan Hi Dan, thanks for feed-back! 73
A difficult job nicely done!
Also let me congratulate you on your excellent command of the English language.
***** Hi thanks for feed back! Well I'm really happy if people can understand my English as it is sometimes hard to express complex coherences...
I know a bit late but tnx a lot! I have now exactly the same issue iand it just helped me to trust in my own abilities to understand to circuit. Since then MXR9745T1 became obsolete and ICOM doesnt stock them. For those who need - any small signal N Channel FET, including BIG rd15hvf1 will work but I used original (china) and tested also 2SK with SO-69 package and modified the bias / gain circuitry. Again, tnx a lot 73! OK2IT
Peter another fine mess you sorted out the worse thing when someone else has been inside and left a mess for you to repair people would be better to bring them to you to fix instead of trying to fix as they could do more damage and give you extra problems to sort out well done to see an expert at work :)
Hello Peter nice video interesting job challenge waiting for a other video
Thanks for a great repair video
I tend to remove all scorched pcb material (and then fill up with epoxy to get flush), especially when its near FETs, as the material often comes down to a few MΩ per square or even lower, and the FETs gates often don't like that at all.
Order out of chaos ......excellent work as always they are all worth saving :)
+John Kerrigan Hi John, thanks for comment, glad that you like it! 73's
Very nice repair Peter- that board was just about a write off! Nice radio though. Yeah I saw that 5.6k on the schematic too and I thought it looked odd! :D
Alan Cordwell Hi Alan, yes the board was really close to write off... The 5,6k was really odd :-) Thanks for comment!!
Espectacular!!! Very nice and interesting repair. Congratulations!!
Mauricio M. Falcao Hi Mauricio thanks so much mate!
What a mess,I admire your tenacity!!
Thanks Colin!
Wow, Peter, another great video. I cannot imagine you would work on a radio that someone else has butchered. I sure do enjoy your videos--you are a top notch technician and teacher/instructor. Were you aware of the "new" heat sync paste that is available now? It has some kinda metal made into the paste which is supposed to conduct heat much better than the white paste. I just heard about it from another Ham. Cheers & 73 from W Rusty Lane K9POW in eastern Tennessee
Terrific video-Enjoyed very much. Thanks for all the effort..............
Satellite_Guy Thanks for comment and that you are still watching my videos ;-)
Paul is the reason i found this channel :)
So welcome to my Channel Donald. All the best and thanks for stopping by 73
Peter , I was hoping to get more info on glueing the copper trace back ?
I have looking around to see what others are doing to glue back old , or put in replacement traces ?
Thanks for your efforts .
John
KD0CAC Hi John, well that is not so complicated. In this case it was enough copper left, so I cleaned the pat that we can solder again on it. Then solder the component first and then put a drop super glue to the pad that's it. If the damage is bigger you take copper foil cut it out like you need it and glue it on the board. Carefully do the through connections and after that put the new component on.. Hope that helps a bit.. Thanks for comment 73 Peter
Thanks so much for sharing this delicate repair with us. Your knowledge and skill is impressive. Keep up the good work. '73 Bob N7ISU
+bobclarie Hi Bob, thanks for the nice feed-back, glad you like my videos.. 73
Thanks for another fantastic video.
rupert handford Hi Rupert, thanks for feed-back!
This problem ive seen before..i burnt out on of my 706's just like this one but with more severe damage than meant the board was not repairable..burnt boards are sometimes resistive, carbon conducts and worse at RF , so even if the track is at the correct resistance to ground via resistors, it could have serious problems at RF frequencies. one has to ask why the pre driver gets so hot that it burns its tracks and fails in the first place.. ive had 5, 706's and they are great radios, cooling is a major issue, the internal fan mod, that we did even on new radios was to add a resistor to the switchable fan supply ( that increases cooling during transmit ) direct to the 12v supply (13.8v) so that the fan runs a little faster all the time and keeps the radio cooler. I even did a 2nd upgrade to my current radio last year during a heatwave as shack temperatures were so high i decided to increase the air flow.. by reducing the resistor value further to increase fan speed.. this mod is recommended for many small high power radios where cooling is critical.
I've repaired boards by inserting a new section having cut out the burnt section and making a copy section from another board , de populated to be able to photocopy and etch a replacement section. not an easy task but its been done with success. having a good section of PCB under the components is necessary to assure sufficient cooling and heat dissipation after the repair. Thicker copper plated boards are better for heat transfer and rebuilding burnt tracks with better boards is recommended. good repair..
I enjoy all of your videos, I wish I had some of the equipment on your very well stocked bench! I see you have a rubidium standard on your bench, do you also utilize a GPS locked reference as well? All the best from KC2IRV
Hi, thanks for feed-back. No I have no GPS reference yet as my rubidium is very stable..All the bst and 73
Hi Peter...I think its Peter, most interesting video and good to see you get the radio working. I've just done similar repairs but my damage was much worse!....L232 supplies 13.7 Volts to the VHF/UHF Power FET because this draws 12 Amps at full power it gets pretty hot...its taken over 10 years but just last week this connection into the PCB was slowly breaking down to finally result in a small electrical fire that created a 6 mm hole right through the PCB!....I had to use Solder Wick Braid to replace damage tracks, I've only just placed power on and all seems okay albeit the power appears a little low on VHF. I lost a small ceramic SMT capacitor that sits just under L232 between ground and the Drain of Q231 but its not shown on the parts layout diagram on page 59 of the Service Manual. In your video I could see the capacitor was fitted, I wonder if you might have information that indicates what its value is and or its circuit reference?....CheersClint - VK3CSJMelbourne
+Clint Jeffrey Hi Clint, the value is 10pf. 73 Peter
Very good job my friend!
***** Hi Yvo my friend, thanks a lot!!
I was looking for specific info , I've been in a lot of trades and can put together lots of things , so I was not looking for general glueing something together .
Specifically traces / pads on circuit boards , finding adhesives meant for that purpose , heat resistive extra .
The most common reason for Q121 to blow out is that R122 was often stuffed with a 4.7k resistor instead of 2.2k, which forces the VGS of Q121 to about 4 VOLTS all the time! That makes it dissipate almost 2 watts continuously. The fix is to either pull the board out and change R122 to 2.2k, or, to simply add a 4.7k resistor from the gate of Q121 to ground, which brings the bias down to around 2 volts, and the idle power down to under 200mW. Lowering the power via the menu on the radio will not change the idle power! You can measure the Vg to ground on Q121 to see if your radio has the issue. If you read around 4V, you need to fix it ASAP. So many IC-706MKIIG are just about to fail due to this error. I will post a video shortly on the details, but the fix is simple and can be done by anyone with a little soldering experience. 73 and great video! de W6EL
I enjoy watching you repair you are a good teacher . may i please send you a sonyi pro80 to repair for me
I have a question about the 706. I have found that every couple of years of operating in the mobile environment, I have to clean/polish the contact area between the metal case and the leaf-spring grounding strips. Do you recommend leaving these contact areas "dry", or using some type of conductive grease?
Hi Alan, yes that is a known issue with the 706. After cleaning I put a very thin layer lubricating oil onto it. www.ballistol.de/90-1-BALLISTOL-Universal-Oil.html This is originally a weapons oil but it is a kind of insider tipp as it works excellent for electronics like potentiometers and switches and everything...Don't know if you can get it but I'm sure you have something similar.. 73
Thank you, I'll consider that solution too.
I have a 706mkiig myself operating in a mobile environment. What happens/problems occur that you know it's time to clean the contacts?
Usually the operation on certain bands start to get erratic - things like TX power varies or won't go to full power, RX sensitivity varies, and in general these things will very/change with vibration, even from slapping the body of the rig. For me, 17m and 40m TX power variation is the first thing I see.
***** I'll watch for that, thanks. That's disconcerting and disappointing to hear! Are these contacts against both the top and bottom covers?
zer gut ! you are the radio maestro !
Fred Suero Hi Fred, sorry for late response, just back from holiday.... LOL thanks for the radio maestro :-) 73
Hi Paul
I have a AOR AR 8200 WIDE RANGE RECEIVER bought the apparently has an error with the S-meter.
The S-meter has permanent full scale.
The receiver has been disassembled ever to renew the backlight.
Did you ever feel like to look over?
Perhaps it would be an interesting video on your channel.
Lg Jogi from Cologne
hi hope ypour still repairing radios sir i have the old 706mk1 i was useing it on 20 watts when hi keyed up to respond to a call i heard a iss from speaker then sudden problem on receiv on hf 20m everythink works normal just no receive 2m band works with signal as normal thanks im in the uk thankyou
Superb video Mr TRX, I love watching you work as you have lots of patience and dont seem to ever let a problem beat you - Just one question for you and this is when peaking out the transmit on a transmitter do you think an analog meter is easier than you're digital one sometimes? I always prefer analog for peaking as a digital power meter I find a little jumpy! But I suppose its a personal choice? Anyway very interesting videos you make and keep up the great work my friend.......All the best from the U.K......
+gripper021164 Hi, thanks for the nice feed back! Yes I totally agree with you, an analogue meter is for alignments much better. Therefore I use my big Philips meter for RX tunings and my R&S Level meter for hf tunings. In this video it was not a precise alignment it was rather more a approximate 100W adjustment and therefore the digital meter is okay. Again thanks for stopping by!
hi all, for anyone who needs the transistors they are the as the pa used on the f3/f3s/f4/f4s/40s hand held radios
GREAT REPAIR !!!
Thank you Joe 73
can u pls fix my Sony crf-1 ? dispaly doesn't work well for fine tuning thx
You sir are the master great repair
kmacla Hi thanks for your nice feede-back! 73
Hello TRX bench. I have a Mk2G which became intermittent in both TX and RX. Since about a week now both RX and TX now gone. Looks like a fault in some common line. Can you give me a lead on what could be possible trouble points. Thanks.
Rahul.
How does one get in touch with you for repairs, love your videos
Hello , I have same this txrx hf not transmitted and receive but the v/UHF working well , I try to open top cover to see is there burn think , nothing found , but I press PTT on HF the fan is worked , due to no work shop in my country how can you help me ?
73
Great repair, tnx for sharing...
Bud...
budleyca1 Hi Bud, thank you!
Greetings dear friend. Could you help me to be in the SET MODE ADJUSTMENT of the Icom IC-706 MKIIG? I don't know the type and configuration of the Plug that is connected to the REMOTE to access its Service Menu.
Good outcome on a job that many technicians would probably not touch. Burnt PCB, dubious components, evaporated traces. Not a good start! My question would be why that pre-driver FET suddenly went short circuit. Your guess that the 5.6 R was incorrectly labelled was a good one, and if that source resistor had been 5.6k the maximum current through the resistor would have been 2 mA but as it is 5.6R, the current is over 2 amps and power dissipated in the resistor would be almost 30 watts, no wonder things got (too) hot! 73 Andrew VK1DA.
Very detailed and interesting!!!
Thanks for watching Joe 73
Nice job! I was afraid the PCB might be a lost cause. I agree that it is worth trying to save good devices rather than junking them.
Robert Calk Jr. Hi Robert, yes in the first moment I saw it I also thought it is lost..Thanks for feed back!
I have Icom 706 MKIIG for many years, now no TX on SSB. FM is working on TX with full power out. Any clues anyone? Thanks
You got some patience dude. . .
One look at that and it would have gone in the trash can if it was me....
Feels good to rescue such a dud though, I have done it, and it feels good.
+cucking funt Thanks for nice feed-back!
Peter
I have mk2g that has stopped both to and rx. VHF uhf seems fine. Very poor sensitivity on hf. Only very strong broadcast signals come through. Obviously some parts that are common to tx/rx have gone bad. How do I start troubleshooting ? Before this happened both the tx and rx became intermittent. Thanks. Vu2yk.
Most likely a problem in the front end. May be video #62 may help and there are some other videos showing the process as well...hope that helps 73
Great repair
thank you
***** Hi Dennins, thanks a lot!
perfect, nice job and very interested to see. Thanks 73 Ernest pa3dlp
+ernest4all Hi Ernest, thanks for feed-back 73
Good job and thanks for sharing
Thanks for watching Joop
Hello there, i am looking for ICOM IC-706MK2 VFO Encoder repalcement parts..
Good work sir greedingd from greece 73'
Realy, realy nice video. Very interesting :)
please help icom ic-7400 TX and RX and PLL / VCO problematic
excellent video..
Thank you Tony 73
good repair
mike charette Thanks Mike!
Thank you, yes it was interesting…
Thank you
Many thanks for an awesome video.
73...dk2ndr
best regards.
Ham Radio DK2NDR Hi Andreas, sorry für die späte Rückmeldung, gerade aus dem Urlaub zurück... Danke für Deinen Kommentar, freut mich das dir mein Video gefällt... beste 73
hello sir i want know how to repair air flow motor in smd plzz tell
Peter you are a great !!! you an collegue ham-radio ? if yes your call ?
those gray coax cables on the circuitboards is it 75ohm or 50ohm?
+biringen 50Ohm
Thanks i have a dead 706. and the coax is damaged. but it had a Relay that went bad before. a fast klikking sound. before it went dead,,, 73 De LA3CLA
Hola buenos días, soy Felipe padilla HJ6GPJ -Colombia. Tengo un radio icom IC 706 MKIIG malo. No enciende. Alguna forma de reparlo o un manual de fallas o reparaciones.
Muchas gracias
Felipe padilla Jaramillo
HJ 6 GPJ
hello, do you know why the icom 706 gone deaf in the vhf part, I tried to check all parts and seen to be fine but the manual does not say where to find the vhf troubles. if you know or have a clue I appreciated any info that you could give me. Best Regards jorge
+jorge marban Hi Jorge, what version of the 706 is it?? What is about UHF and 6m is it working?
I have the first version ic-706, the hf portion works fine but the vhf portion it does not receive well only the very near signals, thanks for reply.
+jorge marban Hi Jorge, no I had another fault in mind. The radio needs to be on the bench for investigation. Sorry can't help you from the distance. 73
Ok thanks I keep.investigating
verry good repair. Thanks for share it
73 Marcel notenboom Pa1mar
Brilliant
Simon Sparks thanks Simon!!
Sir good evening. I am vu2nsk whenever I have time I am watching your video. Now I have one vertex vx7 R .I was put in charge long time the charger was heated and qrt. After I switched on the vx7R nothing happened . I hope it was QRT. SO please let me know what is the problem. Can you give some idea. If I send it to you can you rectify it sir. In India no service person is available.please reply
Well done Peter. 73 de Frank
Thank you Frank 73
hello i need the new pcb diagram thanks
preciso de uma placa do PA do ICOM 706MKIIG
Your good friend should have brought the radio to you firs!
Darryl Landry Hi Darryl, haha yes you are right but I can forgive him as he is far away from my location... Thanks for comment!
thank you....
hussain alonzi Hi Hussain, thanks for comment.
you welcome.
Really enjoy your work and video's. W6WUH
+Capt Larry - I'm glad that you like my work! Thank you 73
I wish you had cleared away the charred area of the board before installing the new transistor.
The previous person looks to have been defeated by the situation and abandoned it to your care.
Well the damage can even get worse so I think it was the right way to leave it that way 73
Im seeing way too many icoms failing....makes me like kenwood even more...excellent job on an ugly mess
73s
I agree Jeff, I like also Kenwood more. 73