Very helpful, technical and well elaborated video. I got in a FT-7800 for repair that suffered from deafness on 2M. Exactly as explained in this video. It turned out the same D1015 was defective. It actually bursted into two pieces, only visible by microscope. I think it was caused because the OM operates with significant RF while having the VHF-antennas in close vicinity. Bought some extra HVC131's in spare... you'll never know ;-) 73's from NL!
I find it interesting that the designers spec parts such that even under a "light" load, no AF for example, the parts still run hot without them attached to a heat sink surface. Imagine it revolves around building something to a cost but my intuition says not so great design practice. Anyway, nice repair as usual Peter, thanks for sharing! 73 - Dino KL0S
Not something a lot of people can do on their own but I make test fixtures for radios like this that I work on a lot. Basically start out with a piece of 1/4" thick aluminum plate and using a Bridgeport milling machine I cut out the majority of the metal leaving pads for the components that need heat sinks. A lot of work but once its made I have it for use in the future. I'm going to be getting some more radios from President to do review videos on. I think one of them is made like this with half the cover acting as a heat sink. I may make a custom test fixture heat sink for it so you can see what I'm talking about.
Great repair Peter and big smile after your "Öhm" at 34:34 min because I had a similar one a few days ago :) Congrats to your new R&S CMS 50. Someday, I'd really like to see a dedicated video on that, if possible. Looks like a great unit. Thanks for sharing your work!
Hi TRX, Plumber heating engineer with limited electronical knowledge. I just bought a second-hand 7800E. So check your site out for reassurance for any future repairs that might be required, looks like well-built radio with fix ability. I love your very well-explained videos. Would it be possible to add a cost of the work you carry out to the radios you repair in normal time obviously without your commentary would be a shorter time to repair, You Have once again entertained and inspired me Thanks Mike Robertson M7 HTO
I love watching your videos and I think they are very successful, useful and we can learn a lot and such things do few people in the world ... I wish you a lot of health and I wish you as many videos as cb and ssb transceivers. Thank you for everything!
Hi Peter, excellent video!! I have the 7900 model of this radio with exact same problem. Poor RX sensitivity on 144 but OK on 220 and 440. At 7:38 of your video I see the signal path split between 200-300 lower path and 108-220 on upper path. So I ran a quick test of sensitivity and sure enough, 200-300 is good but 108-200 is bad!! What PIN part number did you substitute for HVC131TRF?? I need same part. The one you used is larger footprint. Can you please recommend a proper substitute for the TVC131TRF as I will need to order one. Thanks so much for sharing your knowledge and talent!! 73 Dwight N7KBC
I had same problem on FT-7900 , it was PIN diode on receiver side on VHF. I replaced with tougher PIN diode bought from Digikey. it been working fine for 10 years now. PIN diode was damaged, because I transmit 60 watts on 144MHz from another radio , which antenna was only 3 feet away on mobile setup. I usually use two soldering iron with fine tip to remove and solder most of two pin SMT parts AG6JU
Hi I have exact problem with a 7900 on my bench. Poor RX sensitivity on 144 but OK on 220 and 440. Which PIN did you substitute for the HVC131TRF?? Thanks!
Very good job, Peter..as usual. ..Love to see the CMS! As you know i have the 52 series. But dont forget about your CMT and give him some love and hugs from time to time ;-)
That was fun Peter. Sort of a mystery novel. Another great video my friend. You are going to have to talk about that new piece of test gear. Thanks as always.
Goodness me what a fantastic repair. how a little cheeky diode can cause hell of a problem. well done to trace and fix the issue. however it would havebeen better if you could have gone further in testing dual gate mosfet and other components for teaching purpose only by giving in certain signal level at antenna port.
Thank you Adnan, yeah see the point but there are other videos here on my channel showing how to test a dual gate FET for instance the IC7000 video...Thanks for comment 73
Great repair! You can replace the HVC131, that is not available anymore, by an BAP64-02 that has the same size (higher reverse voltage, less capacitance by a slightly higher on-resistance). I did the same repair last year, and for the 8V regulator, the temperature is not critical. The audio amplifier also stays way below it's junction temperature, but I added just another hex bolt to it. Congrats fore the CMS, do you think about making a comparison video explaining the CMT vs the CMS? Would be interesting.
Hi Peter, As so often with these devices, a defective PIN diode. Thank you for the entertainment on Saturday afternoon ;-) I had a cup of tea. You work hard and we look at you comfortably. 73 Bernd
Isnt that a bad solder joint I see @ 21:00? Left center next to what looks like 2 diodes close to each other (parallel)? looks like leg of component poking through joint with space around it...
Hi Peter, thanks for another great repair video. I like the new communication tester. I wonder if you could give an explanation of SINAD in one of your forthcoming videos, thank you, all the best ...................................Berni
I watched the fix and it was great but I also was looking at your Rohde & Schwarz communication service monitor. What a great interment. I went to Rohde & Schwarz web page but couldn't find the communication monitor. Do you know if the monitors are still being made? I would be interested in getting one.
No R&S have now a new model. It is the CMA180. The last CMS has been sold as far as I know around 2010. May be someone can confirm it or correct it here.. 73
Whoa hold it hold it when did the newer R&S com's tester arrive and are you going to treat us to a features video? Great repair by the way we often think pin diodes are so reliable we forget to go back to basics also a video on getting round live board testing with heat sinks removed would be great more and more we see pcbs trouble shooting a problem because the IC,s need keeping cool cheers Peter all the Best Sean
Wow...now that's a sexy new R/S test set !!!! You get to do all the cool stuff....great job as usual...love to see a video on the new gear 73 Jeff WD8JM
very easy, you grab the data sheet of the original PIN diode and then find a new component where the figures are even better. e.g frequency range, RV, Ron, If, P-tot and so on. Sometimes this can take a while
Hi friend. How are you? Just a question, do you know the HF radio technician here in Brazil? Ivo Muniz? From the electronic maintenance company called "alpha telecom"? He is an excellent technician and has maintenance techniques just like you !!! You and he are the example for many others.PARABENS BY YOUR JOB both of you do a sensational job.
Hi Luitz, thank you for your kind words. Of course I know my friend Ivo. We are in contact from time to time. All the best and again thanks for stepping in 73
Enjoyed this episode Peter. Just below where you were working it looks like C1485 and C1451 are missing - any chance these could be the source of the burn mark? Or are these “No Populate” options? Are you sure no one has been in here before - the original soldering on those diodes looked a little dodgy.
Hi Willis, it looks like that those parts are "no populate" options in the E version of this radio. If this parts would have been the reason for the burning marks we surly would see component fragments in the radio but beside the burning mark the radio was clean.. Thanks for watching 73
LOL yeah next time we will have a lab update..No old units are working fine and will remain in the lab set up as there are minor things the CMS can't do. 73
yes Peter Great Video Times you have to go by your feelings weather looking apart lol Enjoy the Repair and got some info from it. love to have that Service Montor , If you have a spare laying around give me buzz, or $2000 USD will do also ? lol lol 73 Peter
Very helpful, technical and well elaborated video. I got in a FT-7800 for repair that suffered from deafness on 2M. Exactly as explained in this video. It turned out the same D1015 was defective. It actually bursted into two pieces, only visible by microscope. I think it was caused because the OM operates with significant RF while having the VHF-antennas in close vicinity. Bought some extra HVC131's in spare... you'll never know ;-) 73's from NL!
Another great repair. It's nice the board can be powered up out of the radio. Sure makes testing a lot easier. Thanks for sharing.
I find it interesting that the designers spec parts such that even under a "light" load, no AF for example, the parts still run hot without them attached to a heat sink surface. Imagine it revolves around building something to a cost but my intuition says not so great design practice. Anyway, nice repair as usual Peter, thanks for sharing! 73 - Dino KL0S
Hi Mike, yes that is helpful for repair but as Dino already said the components are getting really hot so you gave to work very carefully..
Thanks Dino! 73
Not something a lot of people can do on their own but I make test fixtures for radios like this that I work on a lot. Basically start out with a piece of 1/4" thick aluminum plate and using a Bridgeport milling machine I cut out the majority of the metal leaving pads for the components that need heat sinks. A lot of work but once its made I have it for use in the future. I'm going to be getting some more radios from President to do review videos on. I think one of them is made like this with half the cover acting as a heat sink. I may make a custom test fixture heat sink for it so you can see what I'm talking about.
Great repair Peter and big smile after your "Öhm" at 34:34 min because I had a similar one a few days ago :) Congrats to your new R&S CMS 50. Someday, I'd really like to see a dedicated video on that, if possible. Looks like a great unit. Thanks for sharing your work!
LOL yeah a surprised Öhm...Thanks for watching. Yes will do a lab upgrade soon 73
Hi TRX, Plumber heating engineer with limited electronical knowledge. I just bought a second-hand 7800E. So check your site out for reassurance for any future repairs that might be required, looks like well-built radio with fix ability. I love your very well-explained videos. Would it be possible to add a cost of the work you carry out to the radios you repair in normal time obviously without your commentary would be a shorter time to repair, You Have once again entertained and inspired me Thanks Mike Robertson M7 HTO
Great work again,, new communications tester, very nice,thank you Peter for another great video
Thanks Dennis! Yes a new R&S which hopefully will help to speed up throughput :^) 73
You can see the crack in the solder at 38:39 quiet easy on your close up (Cathode end of the Diode you replaced).......cheers good Video as always.
It looks like a bit like a crack..in any case it is bridged :^) Thanks for comment 73
OK! Thanks for the response and your attention, the images are fantastic and the audio very good too.
Thank you glad to hear that 73
I love watching your videos and I think they are very successful, useful and we can learn a lot and such things do few people in the world ... I wish you a lot of health and I wish you as many videos as cb and ssb transceivers. Thank you for everything!
Thanks for your kind words! All the best and 73
Hi Peter, excellent video!! I have the 7900 model of this radio with exact same problem. Poor RX sensitivity on 144 but OK on 220 and 440. At 7:38 of your video I see the signal path split between 200-300 lower path and 108-220 on upper path. So I ran a quick test of sensitivity and sure enough, 200-300 is good but 108-200 is bad!! What PIN part number did you substitute for HVC131TRF?? I need same part. The one you used is larger footprint. Can you please recommend a proper substitute for the TVC131TRF as I will need to order one. Thanks so much for sharing your knowledge and talent!! 73 Dwight N7KBC
Thanks for this! I noticed at 26:43 your hot pocket was ready! I hope it was pepperoni!!
I had same problem on FT-7900 , it was PIN diode on receiver side on VHF. I replaced with tougher PIN diode bought from Digikey. it been working fine for 10 years now. PIN diode was damaged, because I transmit 60 watts on 144MHz from another radio , which antenna was only 3 feet away on mobile setup. I usually use two soldering iron with fine tip to remove and solder most of two pin SMT parts AG6JU
Hi I have exact problem with a 7900 on my bench. Poor RX sensitivity on 144 but OK on 220 and 440. Which PIN did you substitute for the HVC131TRF?? Thanks!
sneaky diode ,,,,, I had a output transistor that would work great then warm up and open curcit ,,,,,they test us some times ,,Great work Peter
Very good job, Peter..as usual. ..Love to see the CMS! As you know i have the 52 series. But dont forget about your CMT and give him some love and hugs from time to time ;-)
Mine is from about 2004 with SSB. Don´t know about software rev., maybe i will read it out by next opportunity
Hi Olaf, yes nice unit. The CMT will remain in the lab set up as there are some little things the CMS can't do...73
I think Peter is probably a brain surgeon as his job - such skilled hands and patience - wonderful.
LOL thanks for the kind words 73
Thank you Peter. That new service monitor made me sit up and take notice! Would it be possible for you to do a video of its capabilities? 73 de Rob.
Hi Rob, yes we will have a lab update soon 73
That was fun Peter. Sort of a mystery novel. Another great video my friend. You are going to have to talk about that new piece of test gear. Thanks as always.
Thank you my friend. Yes going to do a lab update next video. 73
Goodness me what a fantastic repair. how a little cheeky diode can cause hell of a problem. well done to trace and fix the issue. however it would havebeen better if you could have gone further in testing dual gate mosfet and other components for teaching purpose only by giving in certain signal level at antenna port.
Thank you Adnan, yeah see the point but there are other videos here on my channel showing how to test a dual gate FET for instance the IC7000 video...Thanks for comment 73
Great repair! You can replace the HVC131, that is not available anymore, by an BAP64-02 that has the same size (higher reverse voltage, less capacitance by a slightly higher on-resistance). I did the same repair last year, and for the 8V regulator, the temperature is not critical. The audio amplifier also stays way below it's junction temperature, but I added just another hex bolt to it.
Congrats fore the CMS, do you think about making a comparison video explaining the CMT vs the CMS? Would be interesting.
Nice video again Peter. You have an beautiful new toy to play with! I'm lucky to own the same unit.
Thanks Michael, yes we love our toys :^) 73
New com tester nice, could you take a updated tour of your equipment ? Very nice to know what you have and what you use the different equipment for.
Yes we will have a lab update soon 73
TRX Bench and thank you for your very nice videos! I watch them all and love your good guide throug the repairs.. :)
Nice repair Peter. That replacement diode looks like an improvement..
Hi Grant, yes seems to improve the specs.. Thanks for stepping by 73
Hi Peter,
As so often with these devices, a defective PIN diode.
Thank you for the entertainment on Saturday afternoon ;-)
I had a cup of tea. You work hard and we look at you comfortably.
73 Bernd
LOL as long it was enjoyable for you all is fine :^) Thanks for watching 73
A bad PIN diode in a Yaesu? Never happens. :)
Another great repair, thanks for sharing.
LOL how could I forget :^) Thanks for watching Steve..73
Isnt that a bad solder joint I see @ 21:00? Left center next to what looks like 2 diodes close to each other (parallel)? looks like leg of component poking through joint with space around it...
Hi Claude must be a kind of reflection have double checked it . Thanks for comment 73
Hi Peter, thanks for another great repair video. I like the new communication tester. I wonder if you could give an explanation of SINAD in one of your forthcoming videos, thank you, all the best ...................................Berni
Thank you Berne! Well a video about SINAD well might be a god idea. Put it on the list. 73
Thanks Pete..............................Berni
Another great repair ,please keep up the good work !
Thanks for watching 73
I watched the fix and it was great but I also was looking at your Rohde & Schwarz communication service monitor. What a great interment. I went to Rohde & Schwarz web page but couldn't find the communication monitor. Do you know if the monitors are still being made? I would be interested in getting one.
No R&S have now a new model. It is the CMA180. The last CMS has been sold as far as I know around 2010. May be someone can confirm it or correct it here.. 73
That's all you need, A Diode with attitude, great video and great work
So it is :^) Thanks for watching 73
That was a strange little problem. Very nice work. And how about the new test set! Great display on that.
Yes agree it was an odd issue. We will have an lab update soon 73
Whoa hold it hold it when did the newer R&S com's tester arrive and are you going to treat us to a features video? Great repair by the way we often think pin diodes are so reliable we forget to go back to basics also a video on getting round live board testing with heat sinks removed would be great more and more we see pcbs trouble shooting a problem because the IC,s need keeping cool cheers Peter all the Best Sean
Thanks Sean! We ae going to do lab update soon 73
Great to see a master at work well done peter :)
Truly very interesting and beautifully explained. Thank you so much for taking the time to put this together. Superb! (Subscribed)
Glad that you like it Chris! Thanks for comment 73
Outstanding as usual. Thanks for sharing your knowledge for free.
Thank you 73
educatonal videos as always..i wanna learn more about your test equipments peter..thank you
Yes we will have a lab update soon 73
Great repair Peter, nice video. Thanks dear my friend. 73s de Pasquale IW0HEX
Thank you Pasquale and have a nice week 73
Wow...now that's a sexy new R/S test set !!!!
You get to do all the cool stuff....great job as usual...love to see a video on the new gear
73
Jeff
WD8JM
Thanks Jeff, yepp kind of cool the R&S. Thanks for watching 73
Hi, thanks Peter great stuff as always.
Thanks for comment 73
How did you select the replacement PIN diode? Would like to know your process. Thanks Peter for another very interesting video. 73
very easy, you grab the data sheet of the original PIN diode and then find a new component where the figures are even better. e.g frequency range, RV, Ron, If, P-tot and so on. Sometimes this can take a while
Great video Peter, that was a weird track ending between the 2 diodes 73's James
Thank you James! All the best 73
Check with the coil just before d-1015 as it looks burnt to me .
Hi friend. How are you?
Just a question, do you know the HF radio technician here in Brazil? Ivo Muniz? From the electronic maintenance company called "alpha telecom"? He is an excellent technician and has maintenance techniques just like you !!! You and he are the example for many others.PARABENS BY YOUR JOB both of you do a sensational job.
Hi Luitz, thank you for your kind words. Of course I know my friend Ivo. We are in contact from time to time. All the best and again thanks for stepping in 73
Enjoyed this episode Peter. Just below where you were working it looks like C1485 and C1451 are missing - any chance these could be the source of the burn mark? Or are these “No Populate” options? Are you sure no one has been in here before - the original soldering on those diodes looked a little dodgy.
Hi Willis, it looks like that those parts are "no populate" options in the E version of this radio. If this parts would have been the reason for the burning marks we surly would see component fragments in the radio but beside the burning mark the radio was clean.. Thanks for watching 73
Love your videos! Nice job, Peter. 73, Dan
Thank you Dan! 73
is there some trimmer to manulaly increase modulation level on my ft 7800?
no only per software
Where do you find the schematics and breakdowns for these radios?
Dr. Google.. :^)
(PETER THE GREAT) another fine repair and as a bonus no one worked on it first.
Thanks Scott ! 73
Thanks Peter for another great video 73s
Thanks for watching Bob! 73
lol at 34:54 ^^ (a new Communication R&S -tester on start ?)
we love our toys haha 73
Nice detective work Peter ( lol detective did you get it 😂) nice trouble shooting big thumbs up 👍
LOL Thanks for stepping in 73
What model of camera do you use to record your videos?
Sony HDR-CX240
I have the ft-7900r and love it KC3FSP
yes nice unit 73
What are the difference between the new tester and the old one ?
We will have an lab update soon 73
You forgot to induce your new service monitor ;)
Did something happen to old unit , or just found a deal on new unit ?
Thanks again
LOL yeah next time we will have a lab update..No old units are working fine and will remain in the lab set up as there are minor things the CMS can't do. 73
Good eye!!! deN0BPS
yes Peter Great Video Times you have to go by your feelings weather looking apart lol Enjoy the Repair and got some info from it. love to have that Service Montor , If you have a spare laying around give me buzz, or $2000 USD will do also ? lol lol 73 Peter
Thanks Dale! Yes a good servicemonitor is a must. IF I find something laying around I give you a buzz :^) 73
Wow the new communications tester. We need a demo video on that. I wish there would be saturday every day ;)
Yes we will have a lab update soon. Thanks for watching 73
crazy mistake in this TRX :-) .
good job
thumbs up
Yes a bit crazy lol Thanks for watching 73
great job
Thank you 73
I have this radio at my home
forgot to tell you a few videos I suggested you get a new comm analyzer and send me you old unit , want my address
LOL but still need my old one as well :-)