Very few are the times that I wish I'd have chosen a different carrier ,but after watching your videos ,I wish I'd learned your profession. You are a master, Thank you.

A very good video. After watching this I went ahead and started trouble-shooting a Yaesu FT-5100 VHF/UHF mobile rig I bought on eBay. Its display was flashing most of the time and I always suspected the reference oscillator. I located the reference oscillator transistor and measured 0.003 V on the collector, which is supplied through a 100 ohm resistor with 5.0 V. I located the 8 V and 5 V regulator ICs; beefy 7808, 7805 units on the side of the case. They were both working. And I measured 4.98 V in other parts of the radio. Going back to the reference oscillator, I measured around 4.5 V on the high side of the 100 ohm collector resistor. I assumed the 10 uF electrolytic bypass cap. was bad so I yanked it out. That was difficult since the cap is surface mount and surrounded by vertical modules. However I got one pad loose by heating the back side of the board and gave it a good yank. It came free with a small piece of PCB material on the ground plane side. Good enough for gov't work as my former coworkers at NASA used to say. I think I can manage soldering a replacement on the back side of the board. No more blinking display when I powered up the radio, so I programmed it for a local repeater and got good signal reports on VHF . The receive audio is a bit rough, which I think is from the reference oscillator's instability. I am hoping that when I solder a replacement capacitor that problem will go away

Logische Fehlersuche mit der erforderlichen Vorsicht ausgeführt. Das ist der Weg um auch solche komplexen Schaltungen zu reparieren. Wie immer erste Liga Peter. 73, DG3JA, Jörg

As always, brilliant methodical fault finding.

It seems to me that checking the 10 Mhz reference signal would be the first step with an unlock condition and this could be done without removing the board, at the input to the fist 2x stage. I don't mean to criticize your method of getting to the root of the problem. that's just how I would have done it. Your method is more instructional. I truly enjoy your videos, I am a retired electronics technician and a ham.

As always Peter excellent analytical trouble shooting with detailed explanations and verifications shared with the viewers. That was a very impressive video. Thanks for sharing.

Very enjoyable and instructive video Peter, thank you, best regards, Adam, G2AP.

Awesome video love the way you narrow it down block by block keep up the great work 73 from Minnesota Kd9dle

Es gibt nurnoch wenige Elektroniker wie Dich in Delta Lima die sich an diese Geräte ran trauen und auch wirklich wieder funktionell bekommen,.Wenn ich nur 1% von Deinem Fachwissen und praktischer Erfahrung hätte könnte ich mich "von" schreiben. Sehr schönes Video, Peter hab ich gleich auf Facebook geteilt. 💯👌 73 & schönen Samstagabend de Onkel Günter 🙋‍♂

Great Job Peter! :^)

Nice repair. Thanks for sharing and have a peaceful weekend.

Enjoyed the thrill of the hunt...

Another great video Peter, thanks for sharing. 73s Pasquale IW0HEX

Hello Peter - That was one very interesting process of elimination and fault locating. Its a pleasure to watch yo work and meticulously explain each stage of the process. I wonder Peter if you opened up the XO to see which component failed. Many years ago I purchased the Yaesu Twins, the FL101 (TX) and the FR101 (RX). After a week or so the RX lost its LSB function and all I could hear was a very distorted audio. On inspection the LSB filter had snuffed it (died). An associate and myself dismantled the filter and found a dry joint. Re flowed all the internal connections and bingo, back to normal. Great video. 73 de EI6DP

Thank you Peter for another excellent troubleshooting video, 73 SV1FJK

You are a genius sir!!!

I love your videos Peter. Your a great teacher and technician. Have a great weekend. 73

Excellent procedure and result. 👍

Hi Peter, Nice repair. I like your method to determine the defective part. Stay safe. 73 WJ3U

I have no words, just AMAZING! Thanks a lot for your videos! 🔝

Great work!

very nice Peter!

Yet another excellent video Peter.

Yes, Peter is a genius... Best 73s de DL6RDE / AA1KD, Charlie 🍀👍

Good Job Peter

Hi Peter. You lost me when you injected the 40khz into the radio with the R&S generator, in which I'm not familiar. As right off I heard the 1khz tone through the radio. I had to go back and take a closer look at the test setup on the meter. I then recognized the 1khz setting on the opposite side of the setup screen. Thank you as always and have a fantastic week. I'll eagerly be looking forward to your next video. '73 Roger

Hi Peter, I would loved to see an video where you demonstrate the different test eqitment from your lab.

Excellent troubleshooting! Thank you

Yeah, discostyle! Good job Peter! 73 de Olaf!

Great video. As always. Thank you.

Hi Peter here is CX3CP , the same thing happened to me a while ago, but on my HP8921A service monitor, the 10MHZ TCXO also stopped working. I bought a new one and while it was coming, I wanted to open the original just to be curious and see what inside of it, So it has continuous welding on the bottom, terminal side. I used a hot air gun but I couldn't open it. After being exposed to a lot of heat, I put it to the test and it came back to life. So I had it on test for several days and I chose to put it again to the service monitor. finally the new TCXO arrived but I left it as a replacement part, just in case. I'm telling you this so you can do the test to see if that TCXO revives. 73´s

Geflickt! Gratuliere.

Very nice !

thank you

Love to own a radio like that!

Das Pferd von hinten aufgezäumt, aber trotzdem technisch sehr aufschlussreich.

👏👏👏👏👏 & 👍 🙂

A question for Peter or anyone else. As these videos have inspired me to do more modification and repair of my equipment I'm wondering, is a service monitor necessary on a fixed RF bench? If one has a separate signal generator, spectrum analyzer, DVM, etc, is there s special function or convenience that a service monitor provides?

I can never get used to that red light next to TX on Yaesu when the rig is on receive.

Nice fault finding video as always, Peter! Believe a defective OCXO will be a rare fault, but surely can happen. Have you tried an "autopsy" of it? Could be another video?

Hello Peter very nice video. Please how is your probe made that you used to inject oscillating signal. Love your videos. 73 Mike N9GSX

Hi, which can be the reason of this failure Peter? What do you think about this? May be temperature? I have the same transceiver and I have noticed that from the bottom side and with that hardware there is a consistent hot area!!!! After that I know that this radio suffer only the OLED life problem and same encoder issue, the web owner are less or more satisfied about thishardware. Anyway compliment about your very professional troubleshooting ......

tested processer dose not do the same as what you did got new transistors to replace the 7550-a if it dosent work chuck it in the bin

watched one of your video's about the tyt th-9800 got the same problem was you able to fix it

I could have done that job with a Radio Shack multimeter and some Chinese side cutters in about 5 minutes !! lol

Hi peter, any chance of an autopsy of the txco?

how common is this problem ?

where do you buy your parts?

These videos are great. Please keep doing what you are doing. 73 de KJ4ALC

Hi Peter, you explain things so well, I start to think perhaps I could have fixed this radio. I know in the real world I probably couldn't have, but I always learn from you. de Mike G4VQH