#261

#Yaesu, #FT991, #radiorepair

[@ve99online]

Der OM kann sich glücklich schätzen das der Tranceiver in deine professionellen Hände gekommen ist. Für die Vertragswerkstatt ist es ein Armutszeugnis sondergleichen, ich nehme mir heraus das als "Murks in Vollendung" zu bezeichnen. Danke für die viele Arbeit mit diesem Video Peter, ich lehne mich auch gerne zurück und höre einfach nur zu.

[@TRXLab]

Hallo Jörg, immer schön dich hier zu sehen! Ja, ich gebe dir recht, das ist Murks. Der Qualitätsanspruch vieler Werkstätten ist leider nicht besonders hoch...

[@johnm7723]

Still the best radio fault finding videos. Thank you Peter, your detailed explanations are superb.

[@TRXLab]

Thank you

[@susanuciprian9065]

Trx lab is no1🎉

[@marcelobahl7655]

They killed poor FT991A, I'm glad they took it to you to give him a new life, hehehe Big hug and recommendations to the family. Here in Brazil, the one who saves us is Yvo Muniz from Alpha Telecon.

[@TRXLab]

Thank you, Marcelo! Yes, I know Yvo very well, he is a fantastic technician!

[@jblo6822]

Man, Peter, I wish you lived next door to me. I have lots of work for you. Nice job!

[@TRXLab]

lol

[@L.o.u.i.s..]

You know you're good when you can make it look that easy.

[@M0UAW_IO83]

Excellent video and as always a lovely clear fault finding process. Whoever performed that "repair" should have their soldering iron confiscated, just a disgrace. I'm very pleased the radio found its way to you so it could be worked on by a professional.

[@TRXLab]

Thank you!

[@mikefinn2101]

I agree the best fault finding videos on you tube by far I have learned so much from peter I could never repay him for all his help. He is truly one of a kind person on earth. I wish I had his wealth of knowledge, He is so a kind heart to share with others too a real blessing to me. I am sure for others too.

[@TRXLab]

Thank you, Mike, that is very kind and very much appreciated!

[@bblod4896]

Your thorough detective work for this repair makes this video a keeper on my favorites. Thank you Peter. Have a great weekend.

[@TRXLab]

Thank you!

[@w.rustylane5650]

What a great repair and tutorial. I just had to subscribe. I wish I could work on SMD components, but my 72 year old eyes won't work with such small components. I did understand as you were explaining the diode problem. Glad you were able to fix the radio. If my 991a ever gives up the ghost, I'd want you to repair it. You did a marvelous job on fixing someone else's mistakes. I cannot believe a factory repair would look that bad on a 991a. W Rusty Lane K9POW in eastern Tennessee

[@danielepatane3841]

Following your fault findings is really a training to become good tech....thanks so much!

[@TRXLab]

Thank you!

[@charliem.9998]

Yet an other great video by Peter and Olaf ... Thank you so much ... 73s de DL6RDE / AA1KD, Charlie

[@ptronix]

You are like a detective Peter, solving clues at the scene of a crime, great fault finding

[@TRXLab]

Thank you!

[@fitcher-armchair-sleuth]

Great cleanup and fix of messy / bad repair Peter. Always great to watch you track down / diagnose complex (original root cause) issues.

[@albertvanduren1693]

I have learned so much from your patient and thorough teaching. Thank you, and please keep up the excellent work.

[@TRXLab]

Thank you

[@dl7majstefan753]

I tried to understand the thinking of this hero, when he used this glue - but i didn´t. But someone, who tries to cure the symptom instead of the root cause is capable of doing every nonsense. Great repair with a very logical approach dr Peter!

[@CHUCK.H57]

Peter, I think this is the best repair diagnostic explanation I have ever watched. It was very interesting! Your testing logic and reasoning is excellent. Great instruction. Thank you for all your instructional radio repair videos ND5CH

[@TRXLab]

Thank you!

[@pasqualeiw0hex95]

Another great repair my dear friend Peter, compliments ! 73s Pasquale IW0HEX

[@TRXLab]

Thank you my friend, always glad to have you here.

[@hectorpascal]

That was a very "naughty" repair, if it was done by a Yaesu Authorised Repairer. Both mis-diagnosis AND very poor execution. I HATE those RF/PIN diode filter switching circuits with a vengeance! The Yaesu FT757 was famous for leaky diodes in its RF board. I once got so fed up chasing a switching fault that I adopted the "scatter gun" approach. I simply replaced EVERY diode on the board! They were through hole types in those days, very cheap switching diodes (not PIN) and easy to change once the board was out. It worked!

[@ukrainehamradio]

Great job Peter! Thanks for the informative and interesting video! You said a good thing - "now let's think!". It's a pity that so few people do this during repairs and not only...

[@roseelectronics4582]

Welcome back pete

[@jean-francoisgrun7524]

Nice troubleshooting video as always. The switching transistor is 160V 1,5A which is nice. Some radios can handle just a few milliamps. It is a shame that an authorized repair shop did such a sloppy « repair ». Thanks for taking the time to describe everything!

[@Yannis..]

Thank you very much for another interesting and educational video !!! 73 de SV1FJK, Yannis

[@GeorgeWMays]

That was great. A big cup of coffee and a full screen of radio repair on Sunday morning. My compliments to you. Your tenacity and keen attention to the details are admirable. I always learn things from you. Many thanks. Your work is very much appreciated.

[@TRXLab]

Thank you!

[@morseoneuk]

Brilliant methodical fault finding, a pleasure to watch.

[@M5AXA]

Peter, Once again it was great watching you work through this complex fault finding process. And not for the first time we see that you clearly must have one of the fasted parts courier in the world. You waited 1 or maybe 2 seconds and your parts were delivered. The crew of Star Trek would be so jealous. Seriously that was an incredibly interesting video to watch. Have a great week.

[@TRXLab]

Thank you. LOL yes faster than Stark Trek warp

[@intotheblue50]

Loved it, felt all the excitement with you as you worked your way back to the faulty component. Thank you for taking us along with you.

[@TRXLab]

Thanks for feed back!

[@hancecrawford]

Peter trust you are well and thanks again for another video

[@TRXLab]

Thank you all is fine!

[@borayurt66]

Your methodical diagnosis still amazes me after all these years of following your work. You explain what you do and why you do it perfectly, always rolling back a little between each test to see if the conditions of the test from the previous one are still present, which I think is the correct scientific approach. I think I said this before but it is worth repeating once again; I watch your videos with an action movie type of excitement. I don't know what you charge for these repairs but no matter how much, it is worth every penny of it.

[@TRXLab]

Thank you, Bora, very much appreciated..

[@Joe_KS1I]

Wow Peter, your troubleshooting skills truly needs to be at admired. Great job!

[@TRXLab]

thank you

[@13ig13oots]

Most of this goes straight over my head, love the process that goes into fault-finding. I know if any of my radios develop a fault, I'll be sending them off to you.

[@lylewatts6370]

Great video again, I sent my FT-991A to the Yaesu service center in California to repair a non working USB port. They said the circuit board would need to be replaced for around $600 USD. I told them to send it back and I would not use that USB port for that much money. That's $800 CND where I live.

[@TRXLab]

Same in Europe..

[@chevyguy1128]

Excellent job fixing the sloppy repair and getting the radio back to normal. 73's and God bless Peter from Shawn kc9cjc.

[@Superzvision]

Thank you Peter for another mystery solving of radio problems, the proper way. While the other shop didn't really fix the source of the issue, you did it. You're awesome. 👍

[@TRXLab]

Thank you

[@Joe_HamRadioGuy]

Awesome job Peter. I love your work and explanation to find the problem not hide the problem. 👍🏼👍🏼 73

[@TRXLab]

Thank you!

[@BoB4jjjjs]

Very nicely done Sir, and very well explained 😎 👍 You're the man.

[@hancecrawford]

peter most enjoyable fault finding video with much learning video first class repair

[@BobMellor1954]

Thank you Peter, great detail in the video and detective work, 73

[@richardcook4643]

Great video Peter. Thanks for laying out your thought process and showing all the possibilities! It's easy to get loss in the jungle of the schematics. I have no idea of your career path but you would be a excellent teacher!!. Thanks for doing what you do. 73. KM4YTW

[@TRXLab]

Thanks for feedback, Richard!

[@jamescstanley5018]

Excellent and instructive video. Many years ago, when at tech for auto engineering my instructor had a catch phrase, "Test not Guess", something that works across the whole engineering and fault finding spectrum!

[@TRXLab]

true "Test not Guess"

[@wolfhawg]

WOW! A blow torch job. Thanks Peter for another great video. 73s

[@TRXLab]

RND 320 KA3005P

[@lariroli]

Hallo OM Peter, wieder ein sehr spannender Beitrag. Für mich als Oldtimer sehe ich deine Beiträge sehr gerne. 73 Roland

[@KD0CAC]

2 in a row of very good repairs this & the Kenwood TS50 . Thanks again

[@80Loke]

Im always impressed by your works:)

[@rickkennard8027]

Excellent job at detailed explanation of how to really find the problem! Amazing the bad job a "warranty" repair shop did.

[@TRXLab]

Thank you

[@regularuser492]

Unsere KurtzWelle Arzt Peter is wieder am werk, wir bedanken ! ;)

[@TRXLab]

Immer wieder gerne!

[@littlebear5219]

Thank you for great video,and to the removal of the poor work done to the board.

[@joelkist6493]

You have no idea how happy I am to see your video's again. Your technical aptitude is the best! Enjoy all your videos.

[@lyntonprescott3412]

Unbelievably excellent work Peter. Your skill is out of this world! Such logical work is so impressive. Small components? I struggle with valve radios. Many thanks. Best wishes Lynton G4XCQ

[@TRXLab]

Thank you for the kind words!

[@lazkats2712]

The best analytics in the net for radio receivers .Well you re the best!!!

[@robertrainey1728]

Very interesting Perter. Thanks for sharing the repair.

[@izzzzzz6]

Priceless! And talk about timing! I have been putting off this repair for 2.5 years. Yaesu had advised me to look at Q1145 and D1063 so i was quite confident to start the repair. I decided to first take a look to see if anyone else has completed this repair and i found this video. I indeed have 1.4V coming to the switching transistor before it's 1K base resistor. I have 2.16v on the anode of D1113. I just removed D1113 and now have no more connection to ground on pin 2 out for PA switching (which i need PTT to use for a noise canceller i built). I bought the radio like this without knowing. I'll let Yaesu guy in the UK know also. He was very helpful but didn't see this far into the repair. Time to order a new diode. Thanks so much i don't think i would have made it this far. TRX Lab is always top quality! Glad i found the answer right here! And glad i put this repair off till after this video was created! This really made my day! PS. without D1113 in i see 10 Ohms on the PA pin out to ground during Tx.

[@TRXLab]

Great, I'm very happy I could help!

[@rogerlaw8881]

Great troubleshooting again! Thanks Peter.

[@pixeluser175]

Yaesu 991A: The world's best sold 27mc-/PMR-/LPD-transceiver of all time.

[@dirkr7891]

Da kann man nur beten beim richtigen Händler mit Vertragswerkstatt zu kaufen falls es zum Garantiefall kommt. Wieder mal super gelöst das ganze. Toll!

[@jessiec4128]

Another Awesome repair!! I like watching your videos, very good on your repairs.

[@markorrick7558]

Love your posts. Thank You. Very helpful and the information is sensibly delivered in an otherwise very difficult technical environment . Always an inspiration. Thanks ! 👍

[@TRXLab]

Thank you!

[@mikefinn2101]

BTW Peter I re watched your video(s) at times because your attention to detail is so fantastic, I enjoy learning your TR reasoning and thought process. Many thanks real great learning video.

[@jamess1787]

Peter, you do such a good job explaining things. Glad I can follow along and my "assumptions" or "troubleshooting" is valid. 🙂. Thanks for the video.

[@ae1tpa92gwtom2]

Yet another detailed and excellent fault finding Video Peter. 73

[@bundylovess]

Awesome repair Peter big thumbs up

[@kd2eat]

Watching you track back and test the voltage on the diodes was really helpful. It didn't occur to me to consider voltage drop across the resistors along the way, and how that might help you identify which was the culprit. Nicely done!

[@labcat73]

Scary to see an authorized repair center produced such a botch / symptom fix... 😬 And why ffs the glue?! (Ok they could have potted it in black epoxy to hide the shame as well.)

[@TRXLab]

LOL yeah

[@OctavMandru]

Great job, Peter. This detective work is what makes it worth it. And we all can say: "thank you dear (insert the technician name) for not destroying the board in the repair attempt"

[@markusm.lambers8893]

Dear Peter, excellent repair-video, as always! Hats up to the master ! Wonderfull video, and so excellent handeled and narrated, ... ! Now I now, when struggeling with my 'newer' Yaesu-radios, what I should do, ... ! (Have here a FT-991 without the 'A', and man other, ... !) First, connecting you for an apointment ! - That's a woderfull repair, of a wonderfull radio ! - 73 de Markus - db9pz (JN39fq - 5km/3miles east of LX)

[@TRXLab]

Thank you very much for your feedback!

[@wilfredswinkels]

The magician did it again! 😀

[@donalfinn4205]

The Master at work!☘️👍

[@1942Grampz]

Absolutely Brilliant Peter, Well documented, explained, and filmed. This is just what the doctor ordered.

[@kawaja1ctv672]

Lord Peter, you are genius. I really like to see your video. GL 73

[@DonDegidio]

Hi Peter, Great detective work to find the real cause of failure. Wonder why they applied that adhesive during the sloppy warranty repair. Stay safe. 73 WJ3U

[@TRXLab]

Yeah good question...

[@OleF112]

Well done, Peter! Nice description of problem and solution. First time "repair" attempt was..mehh. Ich hoffe, es geht Dir gut! Gruß nach HE! 73 de Olaf

[@TRXLab]

Hi Olaf, danke fürs Vorbeischauen! Ja, das war eine spannende Rep. Hier alles ok, hoffe bei dir auch 73

[@OleF112]

@@TRXLab Alles gut hier am Rhein, lass die Kälte draußen nicht einsickern in den Kelller;-) Der Frühling naht!

[@dxhunter5277]

Thanks for your job. Very appreciated.

[@dennisqwertyuiop]

great video

[@johncundiss9098]

Good video. Older Yaesu 757 are good for leaking diodes. Those are through hole though. I think reason for the adapter is just easiest way to get a plug that fits the radio and adapt it to the RCA plugs of the amp to get your PTT and ALC in/out.

[@vincentwilliams4732]

Thank you for your video nicely expanded fault finding

[@Chris_Grossman]

Excellent troubleshooting and video. When you measured the "output resistance" of the collector to ground the two numbers you saw were actually differences in VCESAT, not resistance. For low the BJT was in hard hard saturation and the higher reading it was in soft saturation. To measure resistance the DVM outputs a constant current and measures the resulting Voltage. The key to the measurement was that that the high reading had conduction and was not an open. The only know way I know it was VCESAT change was seeing the schematic. I would think that the leaky PIN diode might affect the RF performance by changing filter response or adding noise. If that was happening you cured it with the PIN replacement.

[@sergiomackay455]

You are a Pro my friend! keep doing real good job the way IT MUST BE!!!!!!

[@PA3CSX]

Danke Peter für das erklärende video.

[@TRXLab]

Sehr gerne!

[@michaelclutton8446]

Thanks for the video Peter, you have great skill and explain things very well. I enjoy learning from your videos

[@konradkubit6525]

Superb fault finding skills and explanation Peter as always. Happy new year. I suspect the service tech at the Yeasu service faculty would not and did not the patience or time to go in depth. Thank you 😊

[@TRXLab]

Thank you

[@DerekHerbst747]

Hi Peter. Your videos are superb! So much detail and description of your thought process, and all in a language not your own. I speak German pretty well and have tried producing some content in German, which I found to be very challenging. Great respect and thanks to you!!

[@TRXLab]

Thank you, Derek!

[@FUNKLABOR_DL1LEP]

Sympthome und Ursachen sind immer auseinander zu halten.❤ true.

[@TRXLab]

Absolut wahr

[@captlarry-3525]

Brilliant analysis, as always !

[@propagating-radio]

Excellent video! Thank you!

[@spuddyspud8178]

Awesome video Peter

[@boxingday11]

Thanks Peter.👍🏻🇬🇧

[@dondonaldson1684]

It was interesting to see a kludge of an attempted repair by an "authorized Yaesu tech" by attempting to increase the base switching threshold of the switching transistor by the accessory port. It is extremely rare for a PIN duode to fail into a zener mode like that. PIN diodes are used as RF switches and as you say can become "leaky", or in this case become a voltage source when reverse biased. That couple of hours (probably 3 or more actually) is excellent troubleshooting. How could the Yaesu tech button the radio back and return it to a customer in a non-functioning state? There has to be more of a back story than is evident here.

[@berndb.5097]

Hi Peter, there are not enough thumbs up here again ;-) Unfortunately, KZbin only gives me one to distribute..... 73 de Bernd

[@TRXLab]

Thank you so much Bernd!

[@super-8]

Damn they have pop them electronics shit into a new radio design ^^ (Nice Analysis)

[@TRXLab]

lol

[@ouijim]

Wow like watching Mystery Suspense Movie ; ) Thank You.

[@TRXLab]

Glad that you liked it!

[@polymath5119]

Bravo. Thanks for the tutorial.

[@RGB06084]

Thanks Peter!

[@guynardin]

Superb troubleshotting Peter, thank you for share!. I´ll try to use some of your analisis of the schematics in order to diagnosticate an issue with my 991A. It has a poor reception in VHF with a high S9 level of noise floor... It´s not the antena or the power supply..,. so it has to be something with a filter I supouse, I´d love to ear some advice you could give me!. Thank you again for this great video!

[@TRXLab]

well it can be anywhere on the signal path but most likely on the front end...

[@guynardin]

@@TRXLab Yes:. I did a video of it after whatchin you!! kzbin.info/www/bejne/qKa4ZYajapuin6c THANK YOU for the inspiration

[@-freespirit-3314]

Well done 👍🏻

[@lmy5pence481]

Excilint video. Brought back my fault-finding experiences from way back, before surface mounts, and building amplifiers enc. Also worked on TV repairs. Where do you get the outlays (handbooks) of the radios, for the circuit diagrams?

[@lmy5pence481]

@iowahank Ja that's what I did an only found the manual that was provided with the radio. thanks for your help!

[@lmy5pence481]

@iowahank You see that I received the radio with a handheld that said it could go to 430 but it does not go above 28?

[@TRXLab]

80% are on the web

[@forextraderradioman]

Thank you for this interesting and exciting educational video! 👍 vy 73, Dietmar, DL4HAO

[@TRXLab]

Danke!

[@sbelectronicaindustrial6652]

Very, very Good Video.....

[@RideGasGas]

I'm sure you have answered this question many times, but where do you find your schematics and board layout diagrams?

[@TRXLab]

Most of them are on the web

[@markkut9419]

Extremely professional who not allow put component if not fit perfectly. Really difficult fault to find what mean former servicer can't find fault what cause rig odd behaviouring 599+ 50dB 👍

[@jimwolsiffer4397]

Another great video Peter! I have to consider, is this a factory error with wrong part installed? An actual zener instead of the pin? How many other of these could have this defect but owner never used an external PA so doesn't know it? Also wonder how the pulled low rx voltage affected the receiver performance. Anyway you brought it back and that's what matters. Looking forward to the next! 73 Jim WB8ZLK

[@TRXLab]

No, don't think so as the diode we removed was finally a PIN diode..Sometimes they simply go leaky...

[@FUNKLABOR_DL1LEP]

❤Vorschußloorbeeren..