I'm equally intrigued each time you work through the circuits (and in detail) to troubleshoot these radios and thoroughly enjoy listening to your wisdom that has come from many decades of experience.. thank you again!

When all is said and done, only one conclusion. Genius at work.👍☘️

Great video Peter! This has to be one of the most interesting videos that you have made. I thoroughly enjoyed it!

I have an Icom IC-7000 that was behaving the same way. The problem was also one of the finals. It is interesting to watch you troubleshoot the problem because we approached the troubleshooting process differently but both determined the finals needed replacing. I enjoy watching your videos, thank you!

Like everyone else says, excellent troubleshooting technique along with layman's explanation. My hat's off to you sir!

Another good teaching hour to learn more about radios. Thank you Peter

All your videos, lessons really, are most excellent. Thank you very much.

Great Tutorial !! Just knowing where the different placement of the various boards are located, is a wonderful start to getting to the next step in place!! Your showing the physical locations of the PA driver board, and cables, will stick with me when I eventually purchase my own 7300. What a FANTASTIC tutorial!! Thank you TRX Labs!! Your statement of replacing BOTH PA's was interesting. I assume that was done because your logic is that the good PA was way over-stressed, (demonstrated because the 7300 got to NEAR max power-out, with just ONE PA ALONE, causing the life-expectancy of that good, single PA to be radically diminished). The latest firmware installation was ANOTHER point of interest as well!!. I am GLAD that Icom has provided diagnostic information/settings, as well, that is accessible on the front-panel readouts!! Thank you, AGAIN!!

Great video as usually dear Peter, it's a classic defect with RD70HVF1, gate voltage wrong is a bad-signal :-) Best 73s Peter, Pasquale IW0HEX

Fantastic! I own this radio and so I appreciate the peek into the schematic diagram and the beautiful problem solving process. Perfect! Well done! Thank you once again for all you do. It makes a huge difference! 73, de NZ5I OP Kenny (ex DJ0SI)

Thank you for your video it really helped. As you know at the end of this video you showed us the proper way to adjust the idling current. That was very important can you also show use the receive adjustment, the TX power adjustment, TX amplifier adjustment and the frequency adjustment on the icom7300 I have learned a lot from you and to be honest your the only person that I trust with teaching and your attention to detail. Once again thank you from KG5ZLO

I like the way you went through the process of elimination, rather than just going straight to the finals and testing them, It made for a good video. Thank you for sharing! Also, the cord bouncing around the right side of the video is very distracting, lol it kept getting my attention and I would have to rewind what I missed.

Sir, you are an electronics genius...

Crazy point of failure, i never saw a final with that odd "reverse bias". Lucky enough that it did not destroy something around. Good thoughts and conclusions, Peter! Thank you for that video, you did another good job. 73 de Olaf

Wow. So much easier than back four decades ago working on R.L. Drake factory production lines ;-) Make me feel a lot better about my ‘7300. Thanks for this video! 73 de W8IJN

Thank you so much. As a novice license holder, you have highlighted a problem with my IC-7300 that I did not realise I had. it is disappointing when the issue has been identified after the warranty period has expired.

Hi Peter, as an RF engineer I found your troubleshooting method to be excellent. With only ~1dB delta in drive to the final stage, it became apparent that one of the RD70HVF1C n-channel enhancement mode MOSFETs were likely damaged, but it was good to then check biasing of the final stage pre-drivers. As soon as you compared biasing, my thought was one of the push pull pairs was in question. How the fault occurred would be interesting to dig into. The positive gate voltage made the MOSFET operate in full enhancement mode, which means that the good transistor was doing the work. Your recommendation to replace the finals in pairs is extremely good, and it is also important to note that optimally the pairs should be from the same date code so that their operating characteristics are therefore as identical as possible. I appreciate the physical design by ICOM with respect to final layout, but question the choice of Mitsubishi RD70 which is designed for VHF, not HF. There is a note in Mitsubishi's datasheet that comments about this. S11 parameters are centered around 175MHz. "4. In the case of use in below than recommended frequency, there is possibility to occur that the device is deteriorated or destroyed due to the RF-swing exceed the breakdown voltage." So, did this occur? Was the radio being used to cause the referenced breakdown to occur, or did improper idle biasing occur from the microprocessor?

Outstanding fault locating. These new computers, I mean Radios are tough to work on with these PADS components and huge IC's. Well done Sir!

Thank you Peter. I feel further educated about fault finding, about finals adjustment and modern set reliability. I was thinking of buying the 7300, you have taken me a step closer. Regards Andy

Wow, great video. Reminds me of when I was in Navy BEEP school in San Diego many years ago. I do have an ICOM 7300 as well btw.

Great repair video as always! Thank you for teaching us.

Awesome fault finding again as always Peter. Nice to see such a new radio being repaired. I wonder what caused it to fail. The setup for the new finals seemed very easy compared to the old school methods. Let’s hope the software is accurate. Thanks for sharing the repair. Regards Graham

Thank you Peter, Another Great video form you

Thank Trx. Enjoy your the Icom video's as alway very well presented. Well done 👏 ✔️

I agree with the prior comment. Watching Peter's videos makes me want to fix radios. But I would never conceive of the debug process Peter comes up with. Genius.

Hi, I'm a fan of your work, I use Icom 7610 on my radio station, my device is the Japanese version, I receive all the bands in full,

Very good trouble shooting insight!! Peter!!👍

Very interesting repair. I have a friend with a 7300. He has no problem with it yet but I will send him a link to this. Firmware update is more important than I thought. Learned alot from this. Thanks Peter!

wonderful explanation of how to troubleshoot the final transistors !!!!!! Thank you!

I have fixed plenty of IC-7300 with similar problems and almost ever, it is one of the finals which is KO. I will watch the video to see if I am right... Yes, they were bad!. Good reasoning and very instructive. Why do they fail is still an obscure thing... Maybe you are right and the firmware is the culprit. I use to update it also. Another thing which is faulty on that unit is the clock battery, this is the reason it starts at 0:00. It uses a rechargeable battery but goes bad. I use to replace it with a different model, which hope lasts a bit more.

You are the man!! I love watching you work through these repairs

Interesting PCB layout around those finals, looks very much like it's designed for at least a couple of different packages

I just love watching you repair these radios I am not good with electronics but its really great to see you work and explain what you are doing ..Thanks for another great video

Excellent video Peter: Bit of an unusual fault but succumbed to your logical diagnostic process, a pleasure to watch as always.

Show, very didactic and esplanade on how to correct a problem presented in the equipment in which it is maintained, I really like to follow your videos, they are very interesting, rich in details and help us to identify problems in our HF equipment, and vhf in an easy way which favors the technician who will do the maintenance because it is already over a north provided by the owner of the equipment. I like it because the images produced are high resolution and very sharp. Thanks or share, 73s to the friend and respectfully recommendations to family and friends.

excellent tutorial! Thank you for taking the time to share with us!

Thanks Peter, that was a superb video, I have the IC 7300 and have done the 1.4 software upgrade. I am surprised the radio managed 90 watts with only one transistor working. 73 de Mike G4VQH

We break it - you fix it! Good job on that!, Peter! 73's & happy weekend

Once again, as always, excellent tutorial.

Thanks Peter.. I love your thought process, analysis and explanations. It is a pure joy watching the repair videos. I actually have the same issue - different power levels on different bands with my vintage Yaesu FT757 GX2 !!. I applied same elimination process. The input (Base) of TX RF Amplifier on the RF board gets different levels while the level is almost the same on all bands at the Mixer and Buffer. In between is only the band pass filter with many, many switching diodes !! Receive is Ok but I guess some of the diodes might still be leaking - so will replace them all to be sure. Viele Gruesse aus Manila

You are great ..I could watch your repairs all day...

Nice work, excellent procedure. I have that same radio (Icom IC-7300) and already on the second set of final transistors. The first set appear to have been destroyed when my Astron 35 power supply crow-barred, shorting the power supply but also allows a brief reverse current in the radio as it discharges the capacitors inside the radio back through the crowbar. MOSFET's actually operate in reverse bias most of the time; if you reverse the voltage it looks like a big diode and basically a short circuit. Kaboom. Anything that can crowbar the power supply is dangerous for an IC-7300.

Excellent work, Peter. And, the fact you respond to every single comment here deserves great credit. Thank you very much, Sir!

Hallo Peter, wieder einmal so ein schönes repair Video von Dir!! Interessant ist wie ICom in der IC7300 FW den Bias Abgleich selbständig durchführt. Den bias Abgleich mit der neuen FW noch einmal auszuführen scheint mir sinnvoll. Schaden kann es ja nicht und so wie die FW den Abgleich autonom ausführt ist es ja auch sehr einfach und sicher durchzuführen. Klasse Video - PY2BND - 73

Note in video +30 dBm at 50 ohms is 1 watt, so measured drive levels at around +10 dBm would be 10 milliwatts and so forth. that's why in trouble shooting u need a sensitive RF level meter that works at the frequency in question plus down to low milliwatt levels.

Very good troubleshooting Peter, a pleasure as always learning from your experience. Thx for your time, hoping to see next one.

Another beautiful diagnose and repair...... perfect as always..... Thanks

Thanks for the video Peter, great troubleshooting as usual. No mention in the v1.4 firmware release notes about the biasing unfortunately. Looking forward to the next video already!! 73 Brian EI8EJB

Interesting diagnosis, repair and video. Thank you.

Peter do you advise checking the bias periodically to make sure the biasing of the finals are within spec? Great video as always Peter. 73 Joe

Peter you are better than the factory! Respect.

As always great videos. Congratulations and looking forward to the next one ...

That made quite a difference!

I would like to know the power setting of the 7300 when you did the bias adjustment / with dummy load? Thanks..

Great video! A guide for the ID calibration on a IC-7610 would be most welcomed! I'm curious, having been an electronics technician myself (in another life), I find it interesting we never really saw you wearing the ESD strap during repair, however, it appeared that you were wearing it during calibration. I've always been taught to NOT wear ESD when circuits are live (you do not want to present a good ground path)

@TRX LAB Amazing. I have this radio. But I have no SWR protection somehow. If my swr is high the radio still displays whatever wattage (over 50W) on the display without cutting back the output to a safe level. . I'm baffled duly subscribed One question about these RD70HVF1C 164A -G Do they have to have identical numeric alphanumeric (ie the bottom line 164A -G) as I've been looking for the ones you got delivered as spares and can't find them anywhere?

Really enjoy watching you at work👍👍

I heard that it has been well received by other radio amateurs, and this is more interesting to me, but with the fact that the power transistors broke down, I lost the appetite to buy it, what do you say I do a lot of 73 from SV3 CNR Greece !

Very interesting, a rare video on problems on the ic7300!

I really like the fix up of ham gear thanks. De wb8idy in Swansboro North Carolina usa thanks

Great video and troubleshooting flow. I love your test bench! - Thanks!

@TRX Lab, Hello. What was under the final contact , on the board before you applied the solder to the top of the Final contact? Was it a small solder blob under the final contact before you put solder on top?

Where can you purchase the RD70HVF1C finals? I see plenty of non "C" versions. Are they the same?

Thanks Peter, have mentally filed this away in case my YL's 7300 ever develops a problem with the finals! 73 - Dino KLØS

I had in for repair a TS850 a few years ago that had issues with power output , Traced the fault to the IC that to the control signal and switched the relays , It was stuck on one frequency range , from about 4 MHz to 6.5 MHz .... In this range the radio did what it was meant to do , But outside this range as the low pass filters wernt being switched the radios protection circuits cut in and reduced power , As well as seeing a high input vswr due to the wrong filter for that band ..... Just a single IC worth a few £ and it was back up and running again .... Nice 😁

Another good one Peter. Thanks and keep up the good work.

What a very nice radio! And a good job fixing it. I'm glad you didn't check the finals first. Those first few test's were good to see as you narrowed the problem down. Hey have you compared your Multi-Function Tester TC1 against very expensive equipment? Thanks!

I always enjoy your videos Peter and so glad you’re back!

Hi I get no power on 80 and 20 watts max on 40 all other bands are OK Bias on gates of PA are 3.9 on both PA transistors It seems consistently low on 80 but did come good for a few minutes now bad again do you think it could be PA transistors or out put switching..

Hello teacher, what do you think or what did the owner of the equipment tell you about the cause of the equipment failure?

Very clever work and detailed videos thank you. My problem I just encountered with my rig, the MULTIKNOB just started to become tight to turn and LOST the push knob play of it. Any advice for me? Thank you and looking forward to your reply

I really appreciate this video repair. Loaded with useful information as usual. Danke!

I cannot find the Firmware Zip file on Icoms web site. There are all kinds of instructions and manuals but no zip file.

I really admire and fascinated by your RF skill, I was wondering if you have a specific video which explains component and subsystem of a typical VHF radio, so we have better understanding while we watch your performance and repair show

Best Radio on market. Nice internal operation.

I'll go out on a limb here, when I got my 7300, I looked at the issue of the audio amp getting into the RX especially on the AM band as it does but what I did discover was that the screws that hold the PCB's and the screws that hold said transistors to the chassis/heatsink weren't tight. Now I am not saying tightening them until the screws go loose and back off 1/2 a turn :) but pretty much all the screws could do with 1/2 to maybe 3/4 of a turn or more (some where on the verge of being loose) to make them firm. The PWM audio amp in the 7300 (poor design) still is an issue but I solved that with a 7610.

When you have an over voltage on a transistor does it not become saturated? Then it conducts too much current. So you find a bad MOSFET. The funny situation has a remedy. Another case of bad finals. Maybe ICOM has caught the dreaded Yaesu finals problems. What is the major cause of final failures? W Rusty Lane K9POW in eastern Tennessee

Have the settings been altered if so would a factory reset solve the problem or a new firmware install solve the problem or is the problem in the RF stage.

love zis video! hope you will continue to help us comprehend more about radio design and troubleshooting

Have you seen an increase in the number of repairs with the newer radios that are microprocessor aligned? I believe once a customer learns how to get into alignment mode, they can do a lot of damage to the radio. Thanks for the video Peter.

Hi Peter great video! My question to you is when setting the bias can you use a antenna instead of a dummy load? Thanks Peter

Thank you for making this incredible video. It was a wealth of information to me. I was curious why you didn’t test with continuous wave instead of FM unless you wanted to make sure voice works well.

Thank you. This gave me the information I needed to test my 7300's output power. My rig is outputting 100 wats on all bands EXCEPT 40 meters which only outputs 28 watts, and 15 meters which outputs 80 watts. Will running the automated adjustment procedure fix this problem, do you think? 73, de JS2OLO

Thanks for the troubleshooting video. It's good to see your thought process. Can you describe what's inside the diagnostic jack? I presume it enables the diagnostic mode to be used? Something on the lines of a loop back plug I'm guessing. When there was full power on 20m and not on the others, I was expecting the problem to be around the LPF or LPF relays. If you monitored the RF output on 20m would it be grossly distorted as the bias was out or perhaps the stars were aligned for 20m so it appeared to "sort of" work?

According to my research on the internet, this problem is possible by removing two diodes, does this not cause a problem for sending in other bands ??

BONJOUR. Svp ou je peux commander les transistors RD70 ORIGINAL, on en trouve beaucoup sur eBay et AliExpress je ne c et pas si c et judicieux de commander la ba merci à vous.

"saturated" is the term you where looking 4. TNX 4 another great video! 73 N8AUM

Thanks again for another fine video,,, a nice way to set the bias for sure !!!!

I know you don’t answer tech questions, but I’m experiencing lower TX on my 7600, would seem the process is the same as this 7300?

Right now I wish more than ever that you were my good neighbor! My radio died on me (under warranty) and the retailer isn't replying in a timely fashion, blaming the producer... 😞

Great job Peter, my compliments, I have the same problem on my radio, I have already bought the endings, I hope they will arrive soon. Many many thanks, I live in a country where there is no assistance and sending the radio abroad costs me a fortune, maybe not even worth it. So I thank you from my heart, I would like to contribute to your work, but from here it is also impossible to send you money, maybe I can but only with paypal so if you tell me that you can receive them, and you give me your email I do it more than willingly.

show us how to do a mars ode on the Icom 7300 Japan layout from Japan Icom radios layout in the diode section please. I want to open up full transmit on all channels I receive on please. Supposedly just removing of a diode 422 is all one needs to have 0.500-73.000 MHz. Lets see what you come up with.

Good video thanks for the lesson 👍

Great video as always Sir. I really enjoy your explanation while troubleshooting issues. It helps me so much in understanding how things work. Question... Is the RD70HVF1C the same as a RD70HVF1? Sorry for not knowing!

Would have made a nice insight if you had checked the bias voltage on each FET before and after the firmware upgrade 😉

Thank you Peter.....very interesting....can I ask you....does the 7300 have good high SWR protection to protect the finals. Is it unusual for finals to fail on the 7300.

Nice to see you back :)

The adapter cable you used to bypass the antenna tuner so you could directly measure PA output at tuner input, is this cable commercially available or did you build it? If commercially available what is technical name for coax connector on adapter cable so I can search for it? Great video, your channel is a wealth of practical knowledge.

friend good video. a question what was the cause do you think that caused that damage to the equipment?

So If I was to buy a ic7300 would I benefit from doing the service finals set?