Thank you! I was able to get my ic 725 fixed with these instructions. Mine only had two VCO's with the wrong voltage so it would wander in and out of lock in receive and transmit and the DDS loop needed adjusted. Totally running great now. 73!
Super instruction. Have the same fault on IC728, and it has been stby for 4 yrs now waiting for me to fix it. 2 weeks ago found same fault as you show (but belived it to be the 9 v supply), and then not more time for fixing it.. but now seen your instructions, witch save me a lot of time - and gave me inspiration to get on with the repair. Thanks a lot.. rgds fm oz1fjb - ou2v
Peter, thanks for a great video on the 726. I have a used 726 that has been working less 6 meters but now all hf received signals go away and then in a while the radio starts working again. My problem I'm fairly certain will be in the VCO. Great systematic troubleshooting video. many thanks Rich KG5IF
Nice job. Good troubleshoot, and good instincts from prior repairs. I got my ham license finally (upgrading to General for HF use next week). You and other TH-camrs inspired me.
Just a note, Peter. Some years ago, I was having similar wiring problems, so, to overcome the short wiring, I made various leads up to plug between these lead to go into the PCB. It was a pain to get the bits together, but they worked fine for many years. If I come across the sealed package (I have moved house 3 times!!) with these connector leads, marked 'Icom extension leads', then I will forward them to you. They look very professional and served me well. 73 de Tony
Very nice repair Peter. I have seen this in various models of radios in the past. Think it may have something to due with age of components. Thanks for sharing
I got my equiptment out and fixed it it was the same adjustment you did I now have full band coverage.the reading was .7 it was to be 1.0 volts this has a trimmer I adjusted it and bam alset thank you
Hi, and thanks for good video. Again. I have just same kind of problem in 726. But only 8-11Mhz was quiet. Both TX and RX. Nasty fault. There was a PWB strip broken. Someone has put too long screw and this was damaged a foil. Just near DDS loop can... It was 8V supply to syntezizer. Other band get power (reduced voltage) by diodes from band swithing lines. Janne OH6LSL
I have one of these oldies, I learned a lot here when looking for issues with spurious carriers generated from within. It didn't help me find them but I sure enjoyed your video with a pint of ale :) 73 G6MMG
Great video, Peter!!! My FT-450AT does the same thing (dropping static) and always thought it was "normal" for some reason! I need to check to see if I get TX or not when it does this. Thank you! 73 de N0BPS
always a perfect job done! I have to say that the layout of these old radios is a bit messy, to many wiring jumps and components are in the lower side of quality in my opininon....
Peter, Nice repair video. If you had a couple cable extensions, would have made positioning the PA unit easier. :-) Noticed the LP-500 was in use. WB3BJU
And yet another alternate use for the old tooth brush !! And another real good video !!!! I thought you were going to have a problem with adjusting L 30 with it being held by glue, but you had great success in getting it right !!!!!! I learned a few more tipstoday so many thanks !!! I did not realize that such a minor adjustment could make the difference of bringing the circuit to working , Really valuable knowledge !!!!! and so it was a simple fix --------- John A Bellas KC2UVN
But... what was broken? Did someone tinker with that subloop inductor? Did other components age, requiring a change in the inductance? I see that there is some potting compound in place, perhaps to stabilize the inductor (physically). Has this deteriorated? Did you replace the potting? I know, 1000 questions! Thanks for considering these.
Hi Mark, the good news is nothing was broken. It was simply a miss-alignment by aged components. The compound you saw is stabilizing paraffin and it is still good.. Hope that anthers everything 73
Thank you Mike! Yes the LP-500 is great. Minor issues on older radios which are not able to let 200Hz passing for the carrier on spectrum mode. In this case you still need your SA for IM3 tests. 73
I wonder if replacing that little electrolytic capacitor next to the transistor would have gotten the VCO to an usable range without messing with the coil. That thing could not have moved too much, being covered in wax.
TRX Bench I understand, i have watched the whole video. However it is odd to me how that circuit could have drifted that much by itself since that inductor is fixed with wax. If the aging of that capacitor was the cause then it will keep drifting as time goes on and it will require periodic adjustments, something that should not happen. I have designed and built a FM broadcast band amplifier using 2 transistors and the gain at band ends is adjusted in a similar manner, by adjusting the spacing of an inductor, due to my general dislike of trimmer capacitors. So i totally understand that. But i know and you know too that electrolytic capacitors are among the first components to fail in any electronic circuit. Just throwing that out there. My vintage Philips PM3050 dual 50MHz oscilloscope had some noise on the trace when i got it, even with the input shorted. Replacing the capacitors in the power supply fixed it. Still a good deal for ~70 Euro. I've had it for 5 years i think, and i see it mentioned in the 1989 Philips catalog - that makes it 2 years older than I am! Still a good piece of test gear for what i do (mainly SMPS work), but it does fall a bit short with RF circuits. I am currently watching your review of the miniVNA because i am interested in getting one. Greetings from Romania. Andrei
Very nice Peter. Did you add a bit of paraffin/beeswax to the coil to set it in place again? Or I suppose you should simply use the heat gun to soften/re-harden what's there already. I think Buddy is right, probably just aging components that caused the shift. How about the memory backup battery, was it still good?
Thank you Dino!. There is enough paraffin down on the pcb so I just put my hot solder tip into it and done..Back up is replaced. Buddy is right it is a ageing issue. 73
Hello from UK, 2E0EKU I was wondering if this problem can occur from radio getting dropped at some point in its history as that coil seems very sensitive to adjustment?.
Hi John, well hard to say.. of course a hard hit could potentially do that but I believe those hit must be that strong that the housing would be most probably damaged. In our case the problem is simply caused by ageing... Thanks for watching 73
hi great video. my IC R8500 receiver has issue of no audio. squelch circuit is working fine though.pls do a video or some techniques of troubleshooting this
will wait for that. Also if u can do a proper video on how to properly test vhf Rx and Tx and their detail parameter checks.i need to see such video as part of preventive maintenance. rest u r doing wonderful job m such a huge follower of urs. may GOD bless u for doing such free knowledge spreading for us.
Brady Handel ; I know your comment is old but just want to warn you don't try to plug it in direct to the wall, you will ruin it. You need a 12 volt DC power supply.
If you see dots in the Display than it is a realy comon fail for this radio. The goop in the VCO stages become conductive. The best and unfortunate the hardest way is to solder out the components and remove the goop complete. After cleaning up replace all components and aligin the VCO ports. 73
hello , my IC-726 is small power to 6 meter , it is redondante fail ... it is possible research fail to no possible up power all mode ... bad +/- max 2 W fm or +/- 1.5 W SSB ... thank for possible idéa the repair ...
I have the IC-729 on 20 meters the receive would cut out but have transmit turn radio off and turn radio back on everything works but now I have lost 8.000mhz to 14.999mhz I have no transmit or receive could this also be the same problem??
Great video Frischdent paid endorsement? LOL Also Peter if you know someone interested in testing antenna modeling software in German Windows version please let me know. Thanks!
Thank you! I was able to get my ic 725 fixed with these instructions. Mine only had two VCO's with the wrong voltage so it would wander in and out of lock in receive and transmit and the DDS loop needed adjusted. Totally running great now. 73!
Thanks for this video it's very helpful for me fixing the same trouble on this kind of model of Icom IC726
de DV9ARR
Super instruction. Have the same fault on IC728, and it has been stby for 4 yrs now waiting for me to fix it. 2 weeks ago found same fault as you show (but belived it to be the 9 v supply), and then not more time for fixing it.. but now seen your instructions, witch save me a lot of time - and gave me inspiration to get on with the repair. Thanks a lot.. rgds fm oz1fjb - ou2v
Peter, thanks for a great video on the 726. I have a used 726 that has been working less 6 meters but now all hf received signals go away and then in a while the radio starts working again. My problem I'm fairly certain will be in the VCO. Great systematic troubleshooting video. many thanks Rich KG5IF
Nice job. Good troubleshoot, and good instincts from prior repairs. I got my ham license finally (upgrading to General for HF use next week). You and other TH-camrs inspired me.
Hey great to hear that ! Congrats! Have fun on HF 73
Just a note, Peter. Some years ago, I was having similar wiring problems, so, to overcome the short wiring, I made various leads up to plug between these lead to go into the PCB. It was a pain to get the bits together, but they worked fine for many years. If I come across the sealed package (I have moved house 3 times!!) with these connector leads, marked 'Icom extension leads', then I will forward them to you. They look very professional and served me well.
73 de Tony
Yeah Tony right but the problem is you never have the right extenders....Thanks for watching 73
Very nice repair Peter. I have seen this in various models of radios in the past. Think it may have something to due with age of components. Thanks for sharing
Hi Buddy, yes you are right this is a ageing issue..Thanks for stopping by my friend. 73
Excellent work! I think that problems caused not by a smoked chip or such are more difficult to find. Very nice.
Well sometimes yes..Thanks for watching 73
I got my equiptment out and fixed it it was the same adjustment you did I now have full band coverage.the reading was .7 it was to be 1.0 volts this has a trimmer I adjusted it and bam alset thank you
Glad that you find a solution! 73
TRX Bench thank you I aligned the radio the voltages were off. like new very happy glad I watched your video from KN4GTU 73's
@38:05 It looks like there is an electrolytic in the ciruit. Is it not worth changing it in case it has an influence on the changes in the frequency?
@15:46 why not make up some extensions to plug in and have the unit where you want it? Or even cut and extend the wires by soldering in extra length?
Hi, and thanks for good video. Again. I have just same kind of problem in 726. But only 8-11Mhz was quiet. Both TX and RX. Nasty fault. There was a PWB strip broken. Someone has put too long screw and this was damaged a foil. Just near DDS loop can... It was 8V supply to syntezizer. Other band get power (reduced voltage) by diodes from band swithing lines. Janne OH6LSL
Hi Janne, thanks for your report! Always helpful for the community 73
Hi Peter, good repair of this radio, 2 thumbs up. 73
Thanks for stopping by Larry 73
Excellent. I have a 725 with a similar fault - it goes partly deaf at the changeover point of 22MHz. This gives me something to check out, thank you.
Adjusting the VCO coil made a major difference, but it's still not right. More investigation needed.
I have one of these oldies, I learned a lot here when looking for issues with spurious carriers generated from within. It didn't help me find them but I sure enjoyed your video with a pint of ale :) 73 G6MMG
Thanks for feed-back and for watching 73
Best use of a toothbrush I've seen in a while.
LOL yeah that's true...73
Great video, Peter!!! My FT-450AT does the same thing (dropping static) and always thought it was "normal" for some reason! I need to check to see if I get TX or not when it does this.
Thank you!
73 de N0BPS
Thanks for watching Brian, hope your radio is ok...73
always a perfect job done! I have to say that the layout of these old radios is a bit messy, to many wiring jumps and components are in the lower side of quality in my opininon....
Peter,
Nice repair video. If you had a couple cable extensions, would have made positioning the PA unit easier. :-)
Noticed the LP-500 was in use. WB3BJU
Hi Donald, I always have the wrong extensions on hand LOL... Yeah LP-500 is always in use :-) 73
thank you for the video, i just solved my problem with some other receiver from icom. With a similar problem. also made a video about it.
Thanks for this great job. I have just the same problem in my ic725.
Thank you!
I learned a great deal here, Peter. Thank you. I am a Jack-of-all trades, but a master of coffee making (smiles).
LOL Thanks for feed-back 73
And yet another alternate use for the old tooth brush !! And another real good video !!!! I thought you were going to have a problem with adjusting L 30 with it being held by glue, but you had great success in getting it right !!!!!! I learned a few more tipstoday so many thanks !!! I did not realize that such a minor adjustment could make the difference of bringing the circuit to working , Really valuable knowledge !!!!! and so it was a simple fix --------- John A Bellas KC2UVN
LOL yes that's it :-) Thanks for watching and feed-back . 73
was not asking about LP-500 watched that, I was asking about looks like home brew ss station on your bench looks like a speaker etc thanks Peter
Ah got it....It's video 17,18 and 19
Thanks Peter, for another great video, keep em comming, Greg.
Thank you Greg 73
But... what was broken? Did someone tinker with that subloop inductor? Did other components age, requiring a change in the inductance?
I see that there is some potting compound in place, perhaps to stabilize the inductor (physically). Has this deteriorated? Did you replace the potting?
I know, 1000 questions! Thanks for considering these.
Hi Mark, the good news is nothing was broken. It was simply a miss-alignment by aged components. The compound you saw is stabilizing paraffin and it is still good.. Hope that anthers everything 73
@@TRXLab I am sure the wax changes dielectric properties over the years.
Another great repair. Nice to see your new station minitor un use. How do you like it so far?
Thank you Mike! Yes the LP-500 is great. Minor issues on older radios which are not able to let 200Hz passing for the carrier on spectrum mode. In this case you still need your SA for IM3 tests. 73
Thanks! Very fines information and didatics.
I wonder if replacing that little electrolytic capacitor next to the transistor would have gotten the VCO to an usable range without messing with the coil. That thing could not have moved too much, being covered in wax.
Hi Andrei, adjusting the coil is the procedure according the service manual. 73
TRX Bench I understand, i have watched the whole video. However it is odd to me how that circuit could have drifted that much by itself since that inductor is fixed with wax.
If the aging of that capacitor was the cause then it will keep drifting as time goes on and it will require periodic adjustments, something that should not happen.
I have designed and built a FM broadcast band amplifier using 2 transistors and the gain at band ends is adjusted in a similar manner, by adjusting the spacing of an inductor, due to my general dislike of trimmer capacitors. So i totally understand that. But i know and you know too that electrolytic capacitors are among the first components to fail in any electronic circuit. Just throwing that out there.
My vintage Philips PM3050 dual 50MHz oscilloscope had some noise on the trace when i got it, even with the input shorted. Replacing the capacitors in the power supply fixed it. Still a good deal for ~70 Euro. I've had it for 5 years i think, and i see it mentioned in the 1989 Philips catalog - that makes it 2 years older than I am! Still a good piece of test gear for what i do (mainly SMPS work), but it does fall a bit short with RF circuits.
I am currently watching your review of the miniVNA because i am interested in getting one.
Greetings from Romania.
Andrei
Very nice Peter. Did you add a bit of paraffin/beeswax to the coil to set it in place again? Or I suppose you should simply use the heat gun to soften/re-harden what's there already. I think Buddy is right, probably just aging components that caused the shift. How about the memory backup battery, was it still good?
Thank you Dino!. There is enough paraffin down on the pcb so I just put my hot solder tip into it and done..Back up is replaced. Buddy is right it is a ageing issue. 73
hola cómo le puedo agregar la banda de 11 metros a este modelo si me pudieras ayudar te lo agradecería mucho
Hello from UK, 2E0EKU I was wondering if this problem can occur from radio getting dropped at some point in its history as that coil seems very sensitive to adjustment?.
Hi John, well hard to say.. of course a hard hit could potentially do that but I believe those hit must be that strong that the housing would be most probably damaged. In our case the problem is simply caused by ageing... Thanks for watching 73
Nice repair Peter. Would you recommend adding more wax to the sub loop to help keep it stable ?
Thanks Grant. If there is enough paraffin left I would not mix it with another material as you never now how it behaves together. Hope that helps 73
did you check the subloop voltage after you soldered back the cover on the oscillator? metallic covers tend to change the oscillator frequency.
No I testes the functionality afterwards and everything is working fine. 73
great work, better to have a young lady on your bench, what is all in your ssb station monitor ? or did you explain in video I missed,,, Thanks Peter
LOL yes you are of course right :^) Thanks for watching! Yes video on the LP-500 is on-line.. 73
Peter I look forward to seeing your videos. Great Job. KG7SSB
Thank you Dale 73
Hi peter, again a good job!
You are a great coilsqueecer :-D
73
Bernd
LOL yes I'm the best squeezer in town haha..Thanks for watching 73
wow , these are the symptoms my 726 has ...I thought it was dry joints..will let you know how I go with the fix..thanks.
Hi Glenn, would be nice if you are able to fix the problem 73
Hi Peter ,
Very good repair !!
73
Thanks for watching 73
hi
great video. my IC R8500 receiver has issue of no audio. squelch circuit is working fine though.pls do a video or some techniques of troubleshooting this
Hi Adnan, if I get a radio with no audio in, I will do a video! Thanks for watching 73
will wait for that. Also if u can do a proper video on how to properly test vhf Rx and Tx and their detail parameter checks.i need to see such video as part of preventive maintenance.
rest u r doing wonderful job m such a huge follower of urs. may GOD bless u for doing such free knowledge spreading for us.
Great repair video Peter
Thank you David 73
This was a very puzzling problem. How do you think components like L30 could have got out of adjustment?
Hi steve, the coil itself didn't change its value but all the components around did.. Thanks for watching 73
Hi I have the ic-725 but I don't have the cord. What cord would I need to purchase in order to plug it into a wall receptacle. Thank you. 73
Brady Handel ; I know your comment is old but just want to warn you don't try to plug it in direct to the wall, you will ruin it. You need a 12 volt DC power supply.
Hello good afternoon! have a TS-440 this without RX you know if this is a common problem in it this sizzling however do not have strong reception 73
If you see dots in the Display than it is a realy comon fail for this radio.
The goop in the VCO stages become conductive.
The best and unfortunate the hardest way is to solder out the components and remove the goop complete.
After cleaning up replace all components and aligin the VCO ports.
73
Other than that it can be a fault in the front end. 73
Thank you very much my friend
love to get my icom 729 working fully I miss the 20 meter band
I would love to send you the radio or to a place you recommend
Hi Neal, for the US I would recommend Buddy from "The Radio Shop" here
you find all contact details
gokarters.com/smf/index.php?topic=2549.0
please help icom ic-7400 TX and RX and PLL / VCO problematic
hello , my IC-726 is small power to 6 meter , it is redondante fail ... it is possible research fail to no possible up power all mode ... bad +/- max 2 W fm or +/- 1.5 W SSB ... thank for possible idéa the repair ...
I have the IC-729
on 20 meters the receive would cut out but have transmit turn radio off and turn radio back on everything works
but now I have lost 8.000mhz to 14.999mhz
I have no transmit or receive
could this also be the same problem??
Hi Neal, yes that could be possible but a remote diagnosis is always difficult. 73
TRX Bench would I be able to send it to you I feel this video describes the same problem . I am having now
no rx or tx on 8.000.00 thru 14.999.00
TRX Bench sorry about getting back to you so late I just forgot about everything
TRX Bench every band works but that frequency range I gave you
Enjoyed the video. Thanks for sharing! 73...Dan w4mnc
Thank you Dan 73
Peter tnx nice good 73 Peter
Danke Peter 73
good job!
Thank you 73
The toothbrush is the obligatory tool for this kind of. repair ! :)
LOL, yes absolutely right :^) Thanks for watching 73
You have an old lady on the bench lol made me laugh :)
Are you jealous Steven LOL..As long the entertainment factor is given all is just fine, isn't it?? Thanks for watching 73
Yes its great I love the entertainment love your videos. Thanks
My wife listening 'on the side' wanted to know what video I was watching, lol
Great video Frischdent paid endorsement? LOL Also Peter if you know someone interested in testing antenna modeling software in German Windows version please let me know. Thanks!
Okay Thanks John 73