Analog oscilloscope repair 3 - Tunnel diodes 

absolutely!! I want to soak up all of his knowledge

Maybe you were not looking for it :) But of course, only some oscilloscopes contain these.

@@DiodeGoneWild can you teardown another ultrasonic humidifier?

i love seeing the inside of different humidifiers

If I run into another, I will definitely explore it ;)

Used in Tektronix scopes and plugins, including the 465.

Thank you for your support ;) Yes, the TR-0458/B is quite handy!

I've noticed the voltage drops are slightly different, but never thought B-E would be ALWAYS higher. Before I had the intelligent tester, I always used this danyk.cz/test_tr_en.html to verify the C and E.

Yes, I use it mostly to identify the pin outs for C-B-E. Very handy trick.

I kept on waiting for it to spring off and short out when he was hitting the switches. It was super dodgy.

Yeah, I thought the cat might have had something to say about that....

The microphones were mixed together into one signal before being sent on the line. This means the ambient noises were all added together. Sometimes this system didn't really work well. There was a standard alarm loop that could use switches, window foil and motion detectors also. This is where the tunnel diode was used to provide hysteresis when the loop resistance was being monitored. An alarm was initiated when the resistance was out of a set range. In the early 80's the systems installed at the customer were replaced by switches, window foil and motion detectors. It was impossible to use this audio system when the central office was automated. They had a system that was being used in schools. The signal from the intercom system was used instead of microphones. It was set up to listen to various classrooms. The performance of this was even worse. My company did not use this, I just repaired pcbs from another company the was using it. These pcbs were a bit older. Sorry, all this is a bit off topic but I think it might be interesting to someone. The tunnel diode used was 1N3714. It cost about $25 at the time and was hard to get.

Where else? At CuriousMarc, probably.

​@@mrnmrn1I don't think even he has a video containig tunnel diodes.

@@petermikus2363 I wrote 'probably', because I faintly remember he maybe covered them. The amount of vintage test equipment he made videos about, there was agood chance for that. But I just checked, and found no evidence. Maybe he mentioned them in one of his videos. But w2aew made a great video on the topic.

Thanks for your support :). Yes, managing to fix something feels way better than getting something that already worked ;)

v zaujme objektivity je treba aj povedat, ze ked skusite vyfajcit tu diodu, nic moc to nerobi :(

@@8o86 😂stačí výpary s tavidel to je takové svinstvo že se někdy motá hlava. Já preferuji diodu, drogy neberu :)

Představte si, že Tesla v ČSSR takové diody vyráběla pod označením GE130 až 134.

​​@@milanzizka4636To nic nemění na jejich (ne)sehnatelnosti.

​@@8o86😂😂😂

> This is a Czechoslovakian device < - Some components from the Soviet Union are sometimes used in it.

I also noticed, but it measures good. It's actually dirty from old rosin, not burned.

I was wrong 🙊

I had it for the first time a few weeks ago. I was lying in bed for 4 days.

@@1marcelfilms It's not fun, I'd only rate it 3/10.

My doctor got it last year. He's retiring now. Didn't even know who I was or our treatment history anymore. The creature is no joke.

Hoarders have a lot of even more obscure parts ;). But I still sometimes run into something I don't have...

@@DiodeGoneWild where does your collection of obscure components come from?

Old broken items. I have pile of scrap boards under my bench. I often take components off them.

@@simontay4851 many of DGW's obscure components are obviously unused old stock.

I also thought, but it seems to be old rosin.

I also thought, but it's dirty, there's old rosin on it

I also have heaps of them, but still couldn't resist when I recently saw BM566A, which is 2x 120MHz with a DUAL TIME BASE!!! It's home, but the time bases don't work. I will probably try to fix it in one of the future videos.

@@DiodeGoneWild I love collecting old stuff that would maybe end up in the trash but I cant just buy my seventh scope in 2 years for quite a bit of money given that modern scopes are really cheap now

Hell Yeah.!

Boxes on boxes of components... but I still sometimes need a component that I don't have!

@@DiodeGoneWild then Show all the boxes

I don't know of any. Maybe not a part, but a circuitry made od multiple components and some supply voltage.

So you stuck looking through old new stock.. or is that new old stock...@@DiodeGoneWild

Then I hope these are made in Воронеж :)

The cat is at 4:23 ;)

@@DiodeGoneWild Thanks! Your cat is prettier than the 3 Louis Rossman cats!

RU-vid should require every video to include at least one cat.

@@gordonwelcher9598 Daniel's cat is very special: Giving him advice when he is stuck!

Tunelka se naštěstí povedla vyměnit, už trochu dělám na pokračování. Dík za nápady. Ta žlutá LEDka mírně prosvítá při vyšších frekvencích. Ten plastovej elektrolyt C10 se nevejde do rozsahu 100 ohmů mýho měřiče ESR :).

I've heard about that multiple times, but never supported by a solid proof. How is it that it was not damaged here? I really want to know.

He is lucky. The one he tested is still ok.

@@gordonwelcher9598 maybe it's not ok, that's why I'm asking about failure modes. More importantly - how to test it correctly?

Nah: you can slow down the player.