Analog oscilloscope repair 3 - Tunnel diodes
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- čas přidán 12. 12. 2023
- Repairing the time base of the Tesla BM556 analog oscilloscope from 1982. Testing some transistors, diodes, resistors and capacitors, talking about in-circuit testing. Finally, the problem turned out to be a germanium tunnel diode GE134. I don't have the exact type, so I went through datasheets of soviet tunnel diodes and chose the most similar one - GI304A.
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I don't think many of us mind when your videos get 'bloody long'! I could watch your content for hours at a time.
absolutely!! I want to soak up all of his knowledge
I can honestly say that in my 40 years of poking at electronic things I've never come across a tunnel diode in an oscilloscope.
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.
As ALWAYS a great production to follow. Apart from your very methodical fault tracing combined with explanations, the amazing part is you have a stock of tunnel diodes on hand 🙂And just in case someone is wondering about checking transistors with a meter (diode test) the base-emitter reading is always higher (sometimes not by much) than the base-collector. And a very ruff indication is the higher the difference, the higher the transistor gain.....Very ruff 😄
Cheers and thanks as always.
Pete'
New Zealand.
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.
Danke!
Thanks for this explaination.
I've already heard about this type of diode
But nobody explained the properties or use.
Very nice to see the function generator still alive and in action ;-)
Thank you for your support ;) Yes, the TR-0458/B is quite handy!
We want you to upload videos frequently as they are very informative.
Thank You!
5:27 - "talk about working hard, not smart .... ACHOO!" - Pravdu máš LMAO
When you put the new diode on the old legs with just the springy pressure all I could think was "dodgy...."
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....
I used to repair Multigard alarm system control boxes. They used a tunnel diode to give hysteresis in the circuit that measured loop resistance. They did not fail often, I only had one bad one while repairing dozens of control boxes. They ones I worked on were less than 6 years old.
The system had audio microphones installed in each room. The audio was sent all the way to the central monitoring office via leased telephone lines. Each receiving unit at the central office had a level detector. When the intruder made noise it was triggered and the operator could hear what was going on at the premises. Not a very good system, lots of false triggers and it required a lot of the operators time. This was in the late 70's.
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.
Brilliant video and sharing of information - as always. 😉👍
Na toto video som sa veľmi tešil a moc ti zaň ďakujem, skutočne ten obsah stál za to a zabavil ma. Gratulujem ti k (aj keď zatiaľ len čiastočnej) oprave spúšťacích obvodov a na ďalšiu časť opravy sa budem taktiež tešiť.
I had a bad week till now, I thank you for this video!
Where else on the internet could you find an instrument repair centered around a tunnel diode, a component that I'd never heard of until 20 minutes ago, an excellent video. Sorry to hear you're still feeling under the weather with the creature.
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.
I love this channel. Great as always DGW!! Thx ☺👍
Actually, there is the "lambda diode" circuit made with cascaded bipolar transistors, and it has the property of negative resistance, which mimics quite well that of tunnel diodes. But I guess the peak and valley voltages will be quite different than the ones of the diode in your oscilloscope.
To mi pripomína meranie V-A charakteristiky tunelovej diódy v čítači Tesla BM 526. Krásne prístroje.
Awesome video as always 👍😎👍
(Honestly I only seen one video before yours about tunnel diodes, extremely rare component.)
When i soldering sensitive Diode i took a peace of cotton soak in cold acetone or cold alcohol or cold water and cover in diode before soldering. That’s my idea to breakdown heat the diode.
Awesome stuff man!!!
Super video! Ta tunelová dioda je docela těžké zboží na českém trhu 😆 Jednodušší je koupit drogy než tu diodu 😂
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😂😂😂
Ahh, cool!! A revisit on this piece. I almost forgot about it.
Great work.
Nice mate. As usual i learned alot. thanks man
Can't wait for the next episode! :-)
Thanks. I felt quite elated when the triggering started to work.
Thanks for your support :). Yes, managing to fix something feels way better than getting something that already worked ;)
Very Nice !! The only time I saw a tunnel diode used was in some pulse shaping boards for neutron counters. Greetings.
"What do you think about this?"
SSsssuuuper dodgeee. XD
love your vids. pls make more
why is it i can listen to this accent all night long, yet if i so much as hear an accent from the worlds second most populated country, i start SCREAMING? i actually learn stuff on this channel :)
Wow, what a strange part. Its behaviour is fascinating!
VERY impressive job, 👍🇮🇪🙏
Excellent video thumb :)
Maybe we should start a petition to restart production of tunnel diodes.
Or get a bunch of engineers to sit in the middle of the road until this problem is resolved.
Nice repair, I love that old Russian equipment.
> This is a Czechoslovakian device < - Some components from the Soviet Union are sometimes used in it.
what an amazing fix !
my 16B CRO has same problem, and i am yet to understand how to look into it.😞
I had a very mild case of the covid last year. I was only really sick for a few days, then it took about two weeks for the residual cough to go away, and another couple of weeks for the brain fog to go away. It really sucked because I had some super complex projects that I was working on, so basically everything too way longer than normal because I had to go back and check my work from the previous day to find all the mistakes and fix them. One thing that helped was putting everything from my diagrams into spreadsheets so I could keep track of everything and check them off as I went. Probably not so useful when you're repairing equipment rather than building something from scratch though.
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.
I thought I see the resistor 470ohm near the diode is burnt, the one at right angle on side of transistor.
I also noticed, but it measures good. It's actually dirty from old rosin, not burned.
8:25 I love the brute force. Short out the inverter when + is selected on +/-
I was wrong 🙊
You talked about how hard it was going to be find a tunnel diode, yet we all knew that at least one of them was going to show up on your desk at some point; I loved how you tested it without soldering it. One thing I learned today is that you're still 10X smarter than me even when you have viral brain damage ;). I had heard the name, but am pretty sure that I had never seen a tunnel diode until today. Thank you for the repair project.
That cathode voltage from the flyback is dangerous too
Perhaps you could build a small circuit that emulates a tunnel diode?
In cases like this a Schottky diode may work provided it has a quick enough cycle time.
5:30 Cheers mate...🤧
Oooooooooooo tunnel diodes, interesting
I would imagine that GaAs tunnel diodes are a lot more reliable than germanium ones.
Noticed a burnt resistor just below the tunnel diode - had scorch marks on the bottom. Could that be causing problems?
I also thought, but it seems to be old rosin.
had same problem with my c1-55, those diodes can die from old age even if they wasnt used at all
Stará dobrá TESLA Brno.
That is a very obscure part to have in your stock. Or did you buy it?
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.
❤
is there some type of modern part that will work?
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
There is a BM556 up for sale near me but I think its pickup only at 45€....and I already got way too many scopes :D
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
It's a switch.... not a short......❤
Can you make a room Tour and Show your storage of components ?
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
Weird diodes invented by Sony in the 50s. (Just before it was Sony). Quantum tunnelling effect.
I'm sure he checked the diodes both ways!
Yeh getting old sucks. I break apart faster than my lab equipment. If a tunnel diode decided to break, it deserves the burial of champions. xD
That diode transplant ... looks like tree grafting.
There is a buernd resistor next to the diod.
I also thought, but it's dirty, there's old rosin on it
тунельные диоды изготовленные в Воронеже самые лучшие диоды
Then I hope these are made in Воронеж :)
Congratulations! But hey just where is your cat? Hope to see the cat soon.
The cat is at 4:23 ;)
@@DiodeGoneWild Thanks! Your cat is prettier than the 3 Louis Rossman cats!
CZcams should require every video to include at least one cat.
@@gordonwelcher9598 Daniel's cat is very special: Giving him advice when he is stuck!
There's nothing wrong with a clip-on tunneling diode. They look fine.
This s very difficult
2:58 ahahahahaha))))
Diode gone weird
Vadná tunelka umí naštvat, ona se opravdu při sebemenším zahřátí rozletí vejpůl. Chybu automatiky hledej na jejím spouštěcím monostáblu tvořeným tranzistory E17, E18. Na videu se ti nerozsvěcí dioda triggeru, která je na jeho výstupu. Automatika v zásadě generuje spouštěcí impuls, pokud nebyla časovka sama spuštěna vstupním signálem po dobu pár desítek ms. Tady nikdy spuštěný není, takže spouštěcí signál generuje trvale. Já bych sázel na zeleninu, kondenzátor C10.
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 :).
Brain fog, I dont think so. Well done!
A tunnel diode cannot be tested “as a diode” - after that it must be thrown away. They are also extremely afraid of static electricity - in comparison, MOS transistors can be considered "oak" (for example, if you hold a tunnel diode with one hand by one terminal and touch the other terminal with the other hand, it fails due to static discharge electricity)
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?
the thumbnail is very good :D made me click on the video
weird diode
škoda, že to nie je česky
My friend, you have to speak slowly (a bit). Not all of your suscribers have english as mother languaje. From Buenos Aires.
Nah: you can slow down the player.
We want you to upload videos frequently as they are very informative.
Thank You!
This s very difficult
❤