Yaesu FT 817 repair - Part 1: diagnosis
Ғылым және технология
A chance to (re)work on a classic Yaesu FT-817 5W all mode HF/VHF/UHF amateur radio transceiver. I had replaced the finals board - an almost disposable board, and the Achilles Heel of this model - way back in 2021 when it stopped transmitting for the first time in twenty years, according to the owner.
It's back now for a similar symptom, but I think the issue is different this time.
In this Part 1 video, I poke about and develop an hypothesis of the fault that explains the symptoms.
In Part 2: I buy a hot air solder station to do the repair, source parts and have a go! Then we'll see if Part 1 has the right idea of the cause of the fault! In Part 2 also, I share how I measure RF power with a home brew very low power RF meter from Wes Hayward W7ZOI and how I use it in practical situations. Stay tuned and don't forget to like and subscribe...!
Пікірлер: 16
very well presented ..thanks look forward to part 2
@queuerious
9 күн бұрын
@stevenmobile1, thank you! Part 2 can now be attempted as I was waiting to obtain a hot air station for the soldering work. Hot Air Soldering and portable HDD repair: Hot Air Soldering and HDD repair kzread.info/dash/bejne/emaGlNaKh5eogqg.html
Outstanding video! Great explanation of your troubleshooting.
@queuerious
2 ай бұрын
@kruegdr, many thanks for your kind words and thanks for watching.
A repair video that ends in a cliffhanger, subscribed!
@queuerious
2 ай бұрын
@chrisj0, "Will our hero get a decent hot air solder station? will a new FET bring the radio back to life? Stay tuned for the next dramatic installment of Queuerious Guy: Trapped in Electrospace...!"
the same FET shorted during battery charging on my early vintage 817, W4GSM
For me with basic understanding of electronics but knowledge of resistance paths I totally understand your way of thinking. Only de soldering can give you the right measurements but that’s not desirable with those small parts. The FET seems to be the suspect.
@queuerious
Ай бұрын
@prillewitz, Yes, the comments I make about the resistance values I measured are observations that support the hypothesis that the FET(s) is/are dead in the pre-driver circuit. The logic is consistent with a bad FET fault. I am saving up to get a hot air solder station soon and to start the repair. I have another small repair that needs this tool too (a dead portable HDD that I need to get working again). I shall post the repair outcome in a few weeks I hope. Thanks for watching!
Great investigation!
@queuerious
2 ай бұрын
@ukrainehamradio, Дякую тобі!
SIR! WHERE IS THE PART2 OF ERADICATING A FAULTY FINAL TX STAGE OR [PA BOARD] COULD YOU GIVE THE PART 2 OF THIS REPAIR! I AM CURIOUS!
@queuerious
2 ай бұрын
@carl-gunnarhillefors7612, Part 2 is in the works: I need to get paid, get a hot air station, get some practice, do the repair, and test the result… I hope to release Part 2 in the coming few weeks!
@1903A3shooter
Ай бұрын
SAME FET shorted on my early 817 W4GSM
It’s a Yaesu what do you expect, should have bought Icom….
@queuerious
17 күн бұрын
@juniorocicat9573, 😂