#68 Ham Radio Repair: ICOM IC-706 with relay faults on the LP filter board.

We have here an IC-706 with odd behaviour on transmit. All between 0 power and full TX power. Additional to that we were not able to verify the fault description.

[@glaros0]

This repair was a real headache, congratulations for spotting out the problem. I always enjoy watching your videos, your lab equipment is just fantastic (and expensive to built as well!). Thank you,73.

[@TRXLab]

+Kostas Thank you very much Kostas! 73's

[@lyntonprescott3412]

Well done. Intermittent faults are always the hardest to find. 73’s

[@TRXLab]

yepp that is true 73

[@raccoonnyc]

You are a very generous repairman. Most commercial radio repair companies would have returned the radio to the customer upon seeing signs of corrosion. The reason being (as you know), it could take hours (lots of money) and you still may not solve the problem.:) I enjoy your videos.

[@TRXLab]

+raccoonnyc Hi, if the corrosion is only barely visible in a negligible way I always decide for the OM. But it is different if it is a real water damage. In that case you can not take the risk and I fully agree with you! Thanks for watching my videos and all your feed-back!

[@mikefinn2101]

Another great learning experience for me Wow I have one and glad to see a video on it. Thanks Peter Love to watching you do magic

[@technos123]

Another nice repair video. Look forward to your next project.

[@TRXLab]

+technos123 Thank you! 73

[@danielhildebrand6892]

Thank you. This is exactly what mine is doing. I talked for a while on 10m no problem but drop to 40-80 and it would stop transmit. Power on 40-80 was 145w!!! 10m only 35w. I'll pull the RF Filter Board and go thru it. Very informative video thanks.

[@danielhildebrand6892]

I actually pulled the RF board and meticulously reflowed the entire board and reflowed the power transistors. There is that torrid on the top near the transistors and found one leg was just barely not touching the ground pad of one transistor lifted that a bit. Reassembled and it's got 100 watts on all modes it's supposed to have. Will be testing it today if the weather breaks. Borrowed a friend's buddy pole and his POTA hex beam. So let the fun begin.

[@1112223333111]

LP100A-I had this same meter, very nice one I might add. A “W” indicates peak mode, a “w” indicates average mode and a “T” indicates tune mode. For viewers reference.

[@TRXLab]

+ᗒ╬ᗕ1112223333111ᗒ╬ᗕ Hi, yes you are right. More in detail it means that W is PEP peak hold reading and T is PEP > I call it fast attack reading while w average reading is. In the lab I don't need the tune mode as it is made for bur rather more this is in lab use a fast indication whats going on with your signal. And believe me the meter is really fast! Thanks for comment!

[@RupertHandford]

Hi Peter, fantastic video as always and great detective work. Nice job!

[@TRXLab]

+rupert handford Thanks Rupert, yes LOL detective work is the right word sometimes..

[@karlfell3768]

Another great video peter. I suspect that the increased power output also accelerated the wear/damage to the relays. Keep the videos coming, very entertaining as always. Karl..

[@TRXLab]

+Karl Fell Thanks Karl!No the increased output power is not related to the worn relays. I have given a complete answer to a similar question from Dino. Scroll down to Dino's post there you find a comprehensive answer.

[@alwinney9811]

I've had my share of 706's in for repair and oh boy the worst ones have always been either polarity reverse hook ups or lightning surges.

[@rfmonkey4942]

agreed

[@OrbiterElectronics]

Good to see you again my friend. Excellent video as always.

[@TRXLab]

+orbiter8 (John) Hey John good to have you here! Thank you. Take care my friend.

[@grantfullen9559]

Great Repair Peter. Thanks for your videos.

[@TRXLab]

+Grant Fullen Thank you Grant

[@dennisbauer3315]

Thank you TRX Bench, another top video, allways the best.

[@robertcalkjr.8325]

Another great repair. Thanks Peter.

[@TRXLab]

+Robert Calk Jr. Thanks for watching Robert!!

[@user-kj4js4pt5z]

great work peter i always look forward to your videos

[@TRXLab]

+????? ????? Thank you very much, all the best!

[@ngocduong4740]

Do have the pin out for the power plug. Positive and negative power line. Thanks

[@herbertsusmann986]

Good troubleshooting skills! Top notch!

[@TRXLab]

+Herbert Susmann Thank you Herbert!

[@rfmonkey4942]

ah my friend after 10 years at icom i can tell why that happen and when i asked the customer if the used the radio for out band TX with high power the answer was all ways "no not me" i hated doing the filter relays, i don't know why but i did.

[@n1kkri]

A friend has a 706MKIIG that lost all output on only HF. When he presses the PTT light the RED TX light doesn't come on with HF. Works with VHF/UHF. Any tips? How the RED light gets its power might be a clue to why no HF output in all modes. VHF/UHF are working fine.

[@TheDisorderly1]

almost seemed like the fan was acting a bit erratic at about 32:00 or so. Nice job on the repair, thanks for posting these videos. Do you think you have to repair so many icoms because they are popular or because they aren't designed very well?

[@TRXLab]

+TheDisorderly1 Hi, thanks for feed-back. The erratic sound is over the cam only. Well it is always very difficult to conclude from lab repair numbers on design-quality. Well I see differences in designs but in average you have pros and cons over all the different brands. Much more important is the service concept behind a manufacturer and there are indeed differences.

[@thyagarajanp9491]

Hi Peter. This is Thyagu VU2PTR from VU land. I saw your you tube repair of Icom IC 706 which was quite informative and nice presetation. I have a IC 706 MK2G which is refusing to get switched ON ? I checked the glass fuse F591on the PA pcb. It is ok. I checked voltage at the relay RL591on both sides of the contact. Voltage at the down stream side of relay contact going to L613 is not appearing when the power ON switch in pressed condition.When I checked the resistance across the relay coil with digital volt meter shows 460 ohms even when the meter probes are reversed. Will it be a relay contact failure ? As I have very limited test equipment resources request you to help me to proceed further to fix the problem.Thanks.

[@135tvyeah2]

How close is this to the original 706? Mine will fade out on power while transmitting.

[@W1RMD]

Thanks for this. This is a great radio and video. I've had some very intermittent receive problems with mine on vhf ssb. It looks like 14 relays on that board, give or take a couple. 160 watts is pushing this REALLY hard! It don't understand why people try to get every last watt of power out of a radio, particularly a small radio like this one. If anything, I'd rather cut mine back for 100 percent duty cycle, which is way more valuable than maybe one more bar on the receiving end's meter. I wonder if you can rebuild that board? On a side note, I LOVE the vfd display in the power meter! I wish someone could think to make a new production radio with a vfd display in it. 73's- Ryan

[@andreasviehmann5805]

Ich hätte da auch eine Frage bezüglich dem Power Problem. habe auch einen 706 MK2 G von einem OM bekommen, die Sendeleistung in FM bricht teilweise urplötzlich zusammen, in SSB jedoch ist sie dann vorhanden . Das nächste was mir aufgefallen ist dass bei 5W output mit Modulation die Leistung um bis zu 2W einbricht, bei 100W sind es dann 10W weniger mit Modulation. Sehe ich mir die HF am Oszi in dem Fall dann an sieht es fast aus als wenn ich AM moduliere wo bei ich in FM sende. Alles sehr komisch denn er reagiert auch weder auf Kälte noch auf Hitze das kommt irgend wann schlagartig und kommt dann irgend wann wieder mit der Leistung. Ich habe auch das Filterboard in Verdacht jedoch das mit der komisch aussehenden HF bei einem Modulationshub von max. 2,4Khz in FM verstehe ich nicht . Lasse ich die HF zur PA weg und messe direkt auf dem PLL Board ohne Endstufe sehe ich am Oszi in den Spitzen der HF auch ganz minimale Verzerrungen mit Modulation . Wenn ich eine Mailadresse von dir hätte könnte ich dir mal Bilder davon schicken wie das am oszi aussieht. Was auch noch aufgefallen ist , man sieht am Spektrum bei eingestellten 28Mhz komischerweise bei genau 30Mhz noch einen netten Spike stehen der aber schon zu sehen ist bevor der Sender kommt, der bleibt auch stehen wenn ich auf 22Mhz und weiter runter gehe, bei 3,8 Mhz werden es sogar 2 Spikes neben an mit gutem Pegel ! Hattest Du schon einmal so ein Problem beim Icom ? ich hoffe dass er über Nacht morgen wieder seinen Fehler zeigt um weiter messen zu können.

[@dennisqwertyuiop]

Great work thank you for video your a pro always look foward for you repairs \have a great day Peter

[@TRXLab]

+DENNIS N Thank you Dennis!!!

[@marksanderson7921]

Very good information---My Icom 706 filter board has packed up as well and can not get a replacement here in South Africa--It is the pre MK2 so only the 706 :( Any info of where I can order a filter board for the Icom please? ZS1SSM

[@RGB06084]

Well done Sir!

[@TheRadioShop]

Great job at troubleshooting that one Peter. At times fault finding can be difficult but glad to see you nailed it. Next is are you going to rebuild that filter board so when the next one comes along?

[@TRXLab]

+The Radio Shop Hi Buddy, yes sometimes it is horrible when you are not able to reproduce the fault. Thanks for watching!

[@bobmagda6033]

My 706 when in CW mode on all freq starts emitting beeping signal that I can not stop unless I unplug the keyer. I have tried several different keys. Can you help

[@kevingray707]

Thanks for the video. Love watching your troubleshooting. I don't understand how corroded relays would have allowed you to have the 130 to 150 watt output that you had early in the video. I certainly follow the low output but the higher than normal output has me puzzled Thanks Kevin

[@TRXLab]

+Kevin Gray Hi Kevin, thanks for comment and for stopping by. See the answer down below given to Dino. There you find the answer you are looking for.

[@FlexxVision]

The Force of next early Day.

[@TexasCHLforum]

That's another great video Peter, thanks. Is the old filter board worth refurbishing?

[@TRXLab]

+Charles Cotton Hi Charles, thanks for popping in again. Well for a good refurbishment we need all relays new. Each is about 3,5€ or more. So we need to consider parts and labour which makes it difficult to do it cost efficient and beside that it is still an old board without any warranty...So most likely not worth. May be for demonstration and DIY purposes only.

[@misterspock590]

Another great video. Where did you get the new board? Was it new or used and was checked out?

[@TRXLab]

Thanks, it was in my stock tested from an old radio.. 73

[@PapasDino]

Peter - nice troubleshooting effort! Were there in fact two issues here - one the output power level being intermittent as a result of LPF relay failure AND the other a matter of alignment? With the LPF failing why would the output power be increasing? One would think it would only decrease below its spec if the filter is "downstream" from the PA. Just curious. 73 - Dino KL0S

[@TRXLab]

+Dino Papas Hi Dino, very good question my respect! Beside alignment for the max. output power (internally) there is a fact I have missed to tell in the video. The DAC at the CPU is giving a voltage according to the operator hf power setting as POCV value to a comparator (IC1091) as reference. On the Filter unit we have our power detector and our voltage follower OP-Amp which is giving a voltage according to the real output power to the "other side" of the comparator. If the power detector level HFOR is exceeding the POCV level the comparator is switching the output and thus the ALC is regulating the output power down. Normally the HFOR voltage behind the voltage follower on the filter board is approx. 2,3V for 100w output power. The defective board was only able to deliver 1,9V with 150w thus the comparator was not able to switch and the ALC was always asking for more power. That means it is off course an alignment issue but additional to that there is something wrong in the detector circuit too. Thanks for your comment which is very valuable. 73 Peter

[@shahparyanproject8958]

amazing video i enjoyed your investigation my friend, 73 de EP7AHN

[@benalamon4699]

Hello Peter. Where did you order all the parts for the ic 7000? Thanks

[@TRXLab]

Parts are from ICOM Europe

[@seanregan730]

Hi Peter, will the old filter board be refurbished to use again? or will it be scrapped? Interesting fault but why was output power so high was it the golden screwdriver or was it part of the fault cheers Sean

[@TRXLab]

Hi Sean, well if possible I repair the boards or I use it for parts...The high power came from ALC not in place..73

[@MrBugsier5]

found this being a common problem on old vhf Sailor ships radio's, contacts being bad on the relays.. replace the relays and its fine again.

[@TRXLab]

Yeah that's right I swap sometimes the board to speed up the repair but I refurbish most of the time all boards...Thanks for comment 73

[@chilskater]

i bought Japanese version IC-706MK2 S as my first radio..unfortunately i didnt knew tht Japanese version is limited to 10watt for HF..I search high & low for power transmit mod..Method 1 desoldered diodes and adjust LR379..Method 2 desoldered 4 diodes and adjust ALC(correct?)...have u tried any of this mod?

[@latipwinasis2802]

How open tx 2m band icom 706 not mk2g thanks

[@budleyca1]

Excellent video, tnx for sharing... Bud...

[@TRXLab]

+budleyca1 Thank you Bud!

[@hornsby5533]

Sehr lehrreich.

[@DonDegidio]

Peter Another great video.

[@TRXLab]

+Donald D'Egidio Thanks Donald

[@Kenhutchinson100]

Very informative. I have a display problem with my Icom 706. The display gets dark after a while. Do you have any videos pertaining to this problem. 9Z4KH. Operator Kenrick hutchinson from Trinidad, W.I.

[@TRXLab]

Hi Ken, sorry no video on this subject...73

[@bain5872]

I wanted so badly to probe components for a bad solder joint which is what I would have done here. I've found many bad joints this way. Is there a particular reason why you did not do this?

[@TRXLab]

+bain5872 Hi, what exactly do you mean with "probing components for a bad solder point" or better asked what kind of process do you mean. I'm not sure if I got your question right....

[@bain5872]

TRXBench I use a plastic probe to push on the circuit board and individual components, capacitors, resistors, coils.... to expose lose solder connections. I was wondering why you did not use this technique, as there was an intermittent connection. I realize that the problem you located was with faulty relay contacts so this technique would not have been helpful here. I will assume that these particular radios are know for relay failure and lose solder joints are usually not a problem.

[@TRXLab]

+bain5872 Ah okay I've got it now. Yes I have done it off camera... And I thought that there was a reacting area, but it was not.. Thanks for comment and feed back

[@bain5872]

TRXBench Thanks!

[@WFTL14]

Nice work, thanks for sharing!

[@TRXLab]

Thanks for watching 73

[@nigelwright5172]

Hello im a amateur from sydney Aust,i wish we had more techs like yourself here in oz great work ,if any of my gear mucks up id love to send it to you instead of japan iv a ft950 with dmu,ic7000,ft897d and a few more great work PETER. NigelWright vk2pha Sydney.

[@TRXLab]

Hi Nigel, thanks for the kind feed-back and for watching my videos! 73 and Cheers

[@Lindomar850]

Muito bom, amigo, eu gostaria de saber como entrar em modo de serviço, em meu ic-706mkii, pois o manual fala em " enter meter set mode: turn power off, terminate the [remote] jack with a 3.5mm mini -plug. while pushing [p.amp/att] and [tune/call], turn on. minha duvida devo fechar curto neste p2 conector? obrigado! pois tenho somente 30w em hf, e 5w em vhf

[@jassimali4082]

Hi , really good job thank you , i have same problem with radio , the question is how can get new filter board pl's ?

[@TRXLab]

I buy this spare parts from ICOM...Thanks for watching 73

[@4clive]

Nice work, I have repaired four 706 LP boards and all four were from owners who used the radio only on 11m, coincidence?

[@TRXLab]

Yes mate this Radio was used on FM 11 m. Thanks for feed back. 73

[@russellwalker8702]

I have a 706 with problem with relays but unfortunately dont have a spare board i gess have to replace all the relays.

[@rfmonkey4942]

also check the the transistors that drive the relay the inductors in the 12v feed for the relay and assoc bits (what normally happen is 2 or more filter paths are switched at the same time causing this unstable power output or no output at all)

[@ChrisOrtizSirCable]

Another Great Video !! 73s KC3BGT

[@TRXLab]

+Chris „Sir Cable“ Ortiz Thanks you Chris

[@andreasviehmann5805]

Sorry nicht PLL Board ich meinte das mainboard !

[@LawpickingLocksmith]

Nice shack!

[@hans429]

Wenn wirklich das RX/TX relaise defekt ist, hättest dann nicht ne SWR des todes??? Da zerreißts doch die Endstufe oder?

[@TRXLab]

ja schon da aber alle Geräte über die SWR Brücke die Rückmeldung an den Prozessor geben wird die Sedeleistung zurückgereglt und es it keine Gefahr mehr

[@Thomas62611]

This radio is rated at just 100 waþs

[@Thomas62611]

Watts

[@teddean7763]

Love the video love your tech support do you have a call sign ? looking forward to watch more of your video's Do you have a video on repairing a icom 706mkIIg where no audio when speaking into the microphone but radio transmit fine just can't be heard please reply if you have any information on repairing this problem thanks ted Dean KD2ARD USA hope to hear from you soon, 73s

[@rfmonkey4942]

need more info mode band etc

[@RaubfischSzene]

Hello...my ICOM IC 706mkIIg has a Problem with the reception. Sometimes it' s Like Fading (Signal goes down), when i press the PTT...reception for 10 Seconds normal...Thema come Fading Back. Can you Help ne with this Problem? Vy73 Stefan DL7SHK

[@jasonhilaire5515]

nice and informative video. i am looking for ribbon cables for my 706mkiig. can you point me in the right direcrion please... thanks

[@TaterFarmer154]

Thank you much for this video. I am right now having output power issues with my 706mkiig. Hopefully I can find someone who can identify the problem and repair it.

[@RakeshKumar-dg5of]

Why dont you repair led tv?

[@TRXLab]

Well simply because I don't like :^)