Analog oscilloscope repair - tons of problems!
ฝัง
- เผยแพร่เมื่อ 11 ก.ย. 2023
- Restoring a BM556 analog oscilloscope made by Tesla in Czechoslovakia in 1982. Fixing broken and stuck front panel controls, things out of alignment, wires coming off, high voltage arcing and even some smoke! Also a brightness control problem, suspecting a worn CRT, fluctuating heater voltage, testing some transistors. The problem with the heater voltage (coming from the HV power supply) still has to be solved, as well as the bad time base or synchronisation.
The next episode:
• Analog oscilloscope re...
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The sarcasm from the start about Tesla😂
Yeah, that was a good one! I love Daniel's rants.
true story
Honestly a 30 minute video isn't long for people with the understanding of the technology and enjoys the type of videos like this, with us watching you diagnose and repair electronics of different sorts. I would say that the only people that has an issue with a video being 45 minutes to one hour long are the people that have an attention span no longer than 10 seconds, usually it's people that spend all their time on social media, Instagram, etc. those types. The people lack the proper knowledge, skill sets, attention span, fundamental aspects of electronics in general... basically they do not even have any business being on your video in the first place if they are complaining or dislike the fact a video is longer than 10 to 25 minutes. I actually prefer longer more detail oriented and intricate videos so that I can prop me feet up, lean back, and enjoy the deep dive into the details and troubleshooting.
Couldn't agree more. Very well said.
I prefer the longer, in depth videos. I avoid a video if it`s time is listed as less than five minutes (other channels) unless it promises information that I know can be explained in that short time. I have noticed that most people seem to prefer the shorter videos avoiding the longer ones. I`m not sure if this a symptom of or the cause of most peoples technical understanding going downhill. Any video from DiodeGoneWild will be a great video to watch, no matter how long!
My experience is 25 to 30 minutes, multi episodes, seems to cover the widest audience.
, ;)
@@snakezdewiggle6084 I have always been of the opinion that if the viewer thinks the video is too long, they can always skip to the part that interests them. Better to have too much information in a video than not enough. Diode G W has a great webpage as well as TH-cam vids. He has almost every computer PSU circuit diagram, which has been an especially good resource for me. Just do a googler search for his name, Danyk and the word electronics. It should get you there.
It's my least understood complaint in all TH-cam videos. The length of the video is displayed on the thumbnail. It's not like people are being tricked; they're being given the information, ignoring it, then complaining. 🤷♂ And I don't know how one would create a video about fixing an oscilloscope that's short, unless the problem was just a blown fuse? Anyways, I appreciate the long-form videos.
Thanks for putting the bloody effort into videos like this! I'm just a hobbyist, but I always learn a lot from watching your videos. Please know that your hard work is definitely appreciated.
Massive thanks for your support! I'm glad I can teach someone what I've learnt in 3 decades. It's also nice to see people are still interested in these timeless machines :).
That video was worth my annual patreon subscription alone, fantastic. Next time one of my gadgets goes awry I'll just submerge the entire assembly in contact cleaner. The errant CRT display bought back memories of the sixties when, after the national anthem at the end of the evening's transmission, a white dot would appear on the SRT screen when we turned the set off. We would all sit staring at the dot, mesmerized, until it eventually faded.
"...horrible crashing flammable computers on wheels.. " DGW is my spirit animal! :))
This comment should be on the top of the list!
I love to see old stuff being fixed
I would watch every video you make even if they would be 2 hours long, I admire your knowledge and experience around all this stuff and love to learn from it myself, your videos are educating and thorough and you should keep it like this, smart people that knows what all this work is about share the same opinion, we want to learn together. and the other people that don´t know anything about this stuff won´t like the video even if it would be a minute long. But everyone else enjoys it and won´t mind a long video as we are here to learn from it. keep up the good videos and don´t be afraid to put in valuable extra details and time. I´m here for it
Made in Czechoslovakia 💙
I love learning about the design of the old Czechoslovak electronics.
“This one is well, NICE” cracked me up man.
The hunt for the problems is intriguing and engaging. Now I am really looking forward to the next installment. Plus we got the bonus of both the dog and the cat. I liked your description of Tesla cars 😀
Interesting that grey mains suppression filter is a common item in those Tesla appliances. Nicely made oscilloscope. Great to have access to the electrical diagrammes. Those socketed transistors are awesome. Great fault finding. Love the longer videos.
Yes, the TC241 filter is in just about everything. It's in my bench power supply, in the two multimeters with nixies, in this oscilloscope... it's sad they chose to put a paper capacitor in it, instead of polyester or polypropylene!
Thanks for your reply@@DiodeGoneWild
i bet you'd be surprised how many people would be just fine with a long a$$ video as long as its you doing this. I could watch you breaking down schematics and diagnosing equipment for like... ever. I didn't go to school for EE and other than being quite knowledgeable in physics i am almost completely self taught on TH-cam and I've learned more from your channel than all others combined...
I love these longer videos from you. I was enlightened and entertained for the entire time! Please keep them coming.
We had to carry out regular heater voltage measurements on a travelling wave tube amplifier that had the cathode and the heater at -12kV, the meter was placed on a big block of polystyrene foam on top of a plastic chair and the meter leads held off the ground with another plastic chair. Reading the meter was a little tricky as we wouldn't risk getting within a couple of metres of it!
0:12 "It's a different tesla than the one making the horrible crashing flammable computers on 4 wheels." Lol. That made me laugh 😂😂😂
Loool
Hats off to your effort, and that wasn't very long video, it was very interesting indeed, i'm looking forward for the next part/s. Also hats off to the electronic engineers who made these kind of stuff, nowadays ic's solve the most difficult and complex parts of an electronic circuit, you have to appreciate the infinite knowledge those man had back in the day.
Yes, It's hard to imagine how they even designed something so complex. The successor of BM556, the BM566 and BM566A, are even more complex, almost 200 transistors. Two separate time bases, 120 MHz bandwidth. And still allegedly designed all by just 1 person!
@@DiodeGoneWild If the scopes were really made by one person is completely mindblowing, if i had to guess i would say at least 5 people were needed to make these gear, nowadays you need a team of 10 people to design a bridge rectifier lol, that's why everything is so expensive. Moreover nowadays pcbs are made in software which makes everything way way way easier, imagine at that time develop the circuit, arrange the parts in the pcb and make the traces all by hand and just with single layer available and with the smallest footprint possible! Not to mention all wiring, metalwork, and handcraft. Even today 120MHz is not that low end, i imagine they cost at their time a modern equivalent of about $10000. I think i never saw a scope with two time bases, however Dave Jones from eevBlog once mentioned dual time base. By the way, i really admire your building skills, you are the modern equivalent of those old school ENGINEERS as you proved in the sstc and many other projects :)
I love your description of the car manufacturer named Tesla. 😂👌👍
Please continue making long videos. We really learn a lot from them.
I like long videos. Thanks. Looking forward to the next part.
Very interesting, good fault finding analysis as usual! I will catch up on the next video. I myself am struggling now with a ham band transceiver with multiple PLLs out of lock..
What is that radio you are struggling with?
Looks like most of the scope functions are actually working. Pretty good for the old CZ girl. I see some elements from Tektronix scopes of the seventies. Nice FET front end. Good luck with repair!
Currently restoring a Polish V640 FET multimeter from early 80's. Why? Was cheap and broken and corroded from leaking batteries.
Wonderfull as allways. Please continue like this!
Thank you very much.
There is nothing wrong with these long videos. This video I did not notice that it was 34 minutes until I finished it because it is actually fun to watch. I also want to see a video about your set of tungsten lamps and turning them all on and seeing them in action.
Man, I really appreciate the time you spent on this. Very illuminating.
Lovely repair video, very satisfying to watch.
Looking forward to part 2 ( and possibly 3, 4 and 5)
Awesome 👍👍👍👍, can't wait for the next part. I love it!!
"It sets a DC voltage that is going into this 6 transistor contraption" DGW 2023 😎
Если схема синхронизации построена на туннельном диоде, то там есть проблема: со временим ток покоя туннельного диода уплывает и перестаёт работать синхронизация. Если это так, то нужно просто подобрать новое сопротивление смещающего резистора диода и всё будет работать.
That is a beast! Fascinating video
Awesome and your videos can't be too long....cheers.
Nice! Looking forward to the next part!
Top notch video, as usual.
Awesome vid man, as always I learnt heaps, and had a chuckle
You are wise to mention the plastic automaker in this video- the comments generated will game the algorithm and accidentally, some people might learn about troubleshooting repairable electronics!
I would have watched the whole thing even if it was an hour long! Excellent description.
I used those variable capacitor at 5:52 to made my first fm bug 25 years ago.
I always found that the best transistor for that purpose was a bf196 (lockfit). It gave the best audio response when the af was fed into the base. Nostalgia!
Yes bf196 go high in frequency, I also used bfr91 that go even higher .
Great video.
You have the coolest multimeter
Thanks! More videos like this please 🙏
Thank you for your support! More videos are coming ;)
Good effort! Curious to see the next video :-)
Tnx for great video again. I learn alot watching your channel and helping out other people fixing things instead of throwing away. 73 on5gs
Contact cleaner is the new rosin!
thx for your work
thanks for your support ;)
@@DiodeGoneWild
when is the next episode?
S tím triggerem ti držím palce, doufej že to není odstřelená tunelka GE134. S páječkou se k ní ani nepřibližuj, stačí malé teplo a rozletí se vejpůl, je pájená dohromady 😃Prvně bych dostal spouštěcí signál z malé desky pod pakeťákem časovky, pak se případně vrtal kolem tunelky.
Thanks!
It has only one focus control. The other one which seemingly affects focus is an astigmatism control. I think the CRT has a separate electrode for it, it has to be adjusted until the dot is nice and round, instead of elliptical. This control on most oscilloscopes is either only a trimmer that can be accessed only after removing the cover, or it is accessible through a hole on the front panel or side panel. It drives me crazy that they put a knob on it, it is absolutely unnecessary because it only rarely needs to be adjusted. I will remove that knob from my BM566 because I often adjust that accidentally instead of the focus control. I will probably cut the shaft off of the pot, and make a slot on it, so it only could be adjusted with a screwdriver.
I wish I had BM566 :) or even better BM566A. I'd definitely keep it original!
Dankeschön!
TY a lot.
Of course appreciate your effort!!
Want see part2 of the repair.
Bloodylong videos for ever XD
Thank you for your support ;). I'm glad my effor is appreciated! Part 2 is surely coming soon :)
very good
Anybody else get excited when he breaks out the contact cleaner
Multi episodes, 25 to 30 minutes, seems to cover the widest audience on other channels.
, ;)
Danke!
Are you using beer directly for fire extinguishing or after processing?😂
After processing of course as its more directional but what you gain in laser like stream, you might lose in your aiming accuracy!
I’m still used to the one with the Cyrillic lettering on it…
❤
Love your videos !
... and your accent as well.
Thank you very much !
One knob is probably focus, the other is astigmatism.
Probably yes. One has a lot of effect, the other one only has a small effect.
Thanks
thank you ;)
Nice scope, kinda reminds me of the Polish OS352. I love the ceramic terminal strips... pretty much the same kind Tektronix used.
I think you had to use a special low-temperature solder wire, otherwise, the strip could be damaged?
@@beamer.electronics lead-less solder and special technique if I remember correctly.
@@KeritechElectronicsActually silver solder. Tektronix often included some with their instruments.
Thank you. It is great to see how you think through the problems. One thing I'm surprised not to see is any steps to discharge any residual HV. Could you please please address that in your follow-up?
Well, the positive anode voltage doesn't really need to be discharged, because there's no spot where it would be exposed. No risk of touching it when working on it. It would only be a concern in disconnecting the CRT anode connection. And the two negative high voltage supplies have discharging resistors. The capacitors discharge quickly, they are just tens of nF.
Even more contact cleaner!
Imagine taking this whole thing apart... I would probably need to be in isolation for an entire week to put it back together
This isn't dual beam but there were a few Soviet dual beam CRTs, like the 13LO48I and the 16LO2V. There's also the 13LN8 which is a dual beam direct view storage tube used in the S8-17 oscilloscope.
Nice!
It doesn't look easy to get that thing running and also the "custom made" components by the manufacturer, such as that "stereo potentiometer" with 2 different ranges, isn't that fun to deal with. But it will be interesting to follow
Hi Daniel!
So that's what the super cheap Chinese multi meters are for 😂😂
i have been turning volume down just in case every time you powered it :D
... at least, all boards are for the same scope, i have a romanian scope built in 1991-1992, but using boards and parts from 1985-1988, and, more badly, boards and parts from 3 or 4 different scopes! :)
so, a Frankenstein, with a lot of undocumented adaptions and matchings... sweet! :D
It needs adjusting of the balans if the trace "zero" jumps around while changing V/div. Without input you should not see a trace because there is no trigger signal. That is why there is "auto" trigger.
Beauty
I'm getting a broken tek crt Analog scope off a friend and I'm gonna try to fix it and mod it into a cuve tracer. I shall be bugging you Dany.
I would like to old oscilloscope no complicated curcuit board ,understanding simple stages ,very rare oscilloscope . If it produce again it will be get that, more demanding,for technician .😂 I see it had a schematic diagram , try to it makes again ,😂❤❤ GodBless❤
If you want a very simple oscilloscope, look for example at the schematic of BM370. Just 3 tubes :).
@@DiodeGoneWild what is 3 tube ? Please explain again ,🤔
@@NewMicroElectronics-yv1ek think to... uhm, multiple transistors in the same package! :D i think there was even some of those... 4-5 transistors in an 14 or 16 pin IC package, used mainly for measurement and generators...
Osciloskop, kteý je těžší než stůl, na kterým leží.
Hah first time I’ve spotted the burn mark before Dany!
What do I win?
👍👍
29:15 The sockets are keyed by the way...
Woohoo! Old capacitor testing coming next!
I don't know why I love watching bad capacitors being tested, it's not like the what I see is going to be beneficial in any way shape or form!
But watching someone do all the proper capacitor tests and not just ESR is not very common....
To many times I see people who only test for ESR and get a good reading even though I can see from the other side of the screen that it's top is expanded or leaking electrolyte.... And they called it good!
There's also a lot of people who test a capacitor for capacity and when it reads over it's rating they think that it's good.... If a capacitor read's over it's rated capacity, it's bad! It's most likely suffering from voltage losses due to high parallel resistance which is also DC biasing whatever is downstream and setting things up for an expensive cascading failure of components that are probably no longer available!...
So yeah, I'm looking forward to seeing many capacitors being tested....
Yes, definitely some testing in the next episode ;). It will be public tomorrow, my Patrons can already see it.
@DiodeGoneWild Meh who cares Daniel tjat video is getting long.. We love yours bloody long repair videos and sense of humour too.. 😎😎
Tbh I really want to see DWG fix some Tesla Motors product. I know he enjoys his share of fixing his country's automotive products!
Who'd like to fix something made not to be fixable. It's like 10% of the effort to actually fix it and 90% of the effort to overcome the obstacles purely made to stop you from fixing it. No longer enjoyable.
@@DiodeGoneWild In reality Teslas are not any less fixable than other cars. It is not like you get schematics for other cars...
But they should get the schematics :). Or at least, the parts shouldn't have serial numbers specifically not to work without reprogramming using 100 000 USD tools. Modules should not disable themselves after being unplugged and replugged. All these things, that claim to be for safety and against theft, but in reality they are to erradicate DIY, aftermarket parts and 3rd party repair, just to make more money.
@@rkan2 You actually CAN get at least block diagrams for a lot of cars. Not necessarily just online for free, but at least they exist outside the manufacturer's systems.
@@DiodeGoneWild 100% agree
@DiodeGoneWild Any idea how to fix the line not display horizontal? The fuse in my oscilloscope blew and after recovery, the line isn't horizontal anymore. Unfortunately I don't have the schematic to look at. I assume it has to do with the board that control the tube but doesn't know where to start.
😔😞 friends ....
Ďakujem za toto video a mne sa páčilo, že bolo také dlhšie, lebo tam bolo mnoho zaujímavého obsahu a budem sa tešiť na ďalšiu časť. Ak ti môžem poradiť čo sa týka tých objímok na tranzistory, tak som si všimol, že na tých objímkach je výstupok (plastový) tam, kde má tranzistor tiež výstupok (kovový), takže podľa toho sa podľa môjho názoru dá orientovať, len by som si pred vytiahnutím každého tranzistora (samozrejme len tých, ktoré bude treba vytiahnuť) pre istotu overil či tie výstupky súhlasia, niekde mohol pracovník pri osadzovaní pozabudnúť a nemusel osadiť objímku správne výstupkom súhlasiacim s výstupkom tranzistora, pritom elektricky to môže byť správne aj tak, lebo čo som si všimol, tak tranzistor ide osadiť ľubovolne.
Spoléhat na to nelze. U svého jsem měl nefunkční kanál A, během jiných oprav jsem tranzistory vytáhnul a podle výstupku vrátil. Po mnohých hodinách strávených nad hledáním závady jsem proti osazováku zjistil, že v závodě otočili celou patici špatně, po otočení tranzistoru samozřejmě kanál ožil. Takže vždy podle osazováku, na patice bych ohled nebral 😆
@@teslakovalaborator Súhlasím s tým, že sa na to netreba spoliehať, preto som aj písal, nech si pred vytiahnutím daného tranzistora skontroluje, či výstupok na pätici súhlasí s výstupkom na tranzistore, ale máš pravdu, že podľa osadzovacieho plánu je to najistejšie.
I think you used too little contact cleaner. I think it needs more contact cleaner.
Maybe moar salt too?
Instead of put contact cleaner in the scope, the scope should be put in contact cleaner 😅
bro cooked the whole career of Elon musk in 5 seconds
A/B button for syncro
Does the HV transformer in the oscilloscope look like a TV flyback? I have only seen scopes with 50 Hz iron core transformers with n*100 V winding for the voltage multiplier.
Depends on the age, very old ones were mains derived but the newer ones use what looked like a small flyback or other small ferrite transformer. You may not see it as it may be potted or covered in an EMC screen.
That's the most complicated brightness control ever 😅
This BM556 is still not as overcomplicated, only 86 transistors. The newer type BM566 has 173 transistors :). I'd like to find one in a repairable condition some day...
Great video, but I need to add that it's not a good idea to spray contact cleaner into an oscilloscope, especially into the Y divider. The oil can seep in-between the plates of the compensation capacitors, changing their capacitance a lot, it can screw up the aligment so bad that even a 1kHz square wave will look bad. Soaking oil into the phenolic boards of the wafer switches in the Y divider can have a similar effect. I started using a 100MHz Kikusui oscilloscope at work about 15 years ago, and did not understand why it is so horrible, the slope and edge of square wave looked different in each sensitivity setting. Then my colleague told me the scope needs contact cleaning annually, because the range switch is flaky in it. The compensation got screwed up by the oil from the contact cleaner.
I used WD40 contact cleaner for sensitive electronics on all the controls and some sliding switches on my scope. It leaves no oil or residue.I used some deoxit on the rotary switches.
Well, you're right, but the sensitivity switch was so stuck, it was either a bucket of contact cleaner or a hammer. I hope most of the contact cleaner went into the switch and the shaft bearings. The capacitors are outside of the shielding box. If it got into the capacitors, I probably could flood them with a brake cleaner, it evaporates with no residue.
@@DiodeGoneWild Yes, brake cleaner might help if it went into the capacitors. I have to replace a bunch of the compensation trimmers in my BM566, because they are broken, most likely from the factory!
How did you get the electrical schematic?
hi ! my analog oscilloscope (16B) is having trigger issue i think, the display signal is not stable, and suggestions ?
This video was sponsored by Uni Credit bank😂
Made by Tesla. Not to be confused with that car company, Tossler? 😜
i really love how Tesla is now a pure pun, mainly in DGW's videos!... a czech using Tesla parts, even Tesla was serbian, and the wellknown cars are built in China by a firm owned by a south-african with lots of citizenships... :))))))))))))))
can u help me to diagnose my oscilloscope problem with readout never show on screen buat if i turn on 1 hour readout show on the screen, oscilloscope gw istek gs625
If I had something to see if you wanted it, how can I contact you?
contact me using danyk at centrum dot cz
When the content is interesting why not make it as long as necessary.
Definitely no problem with extending lenght of video, I was just setting down when things were getting intriguing, you broke off - a part 2 perhaps??
Your manipulation struggles with need for extra hands, have you thought of employing your cat (obviously of high intelligence😽) to lend a helping paw! Doggie might help but perhaps cannine intellectual capacity not so profound.😂
The HV supply is crook
You were way more fun before , u talked louder. You're toooo quiet right now
He clearly dislikes EVs though he doesn't have one. You should at least try them before judging about them.
One EV maker doesn't equal all EVs in general. I have nothing against EVs as long as they're not designed to work against their owners.
@@DiodeGoneWild based
Maybe you should try to stop being such a tool.
please no i hate shorts
PLEASE stop poking around with a screwdriver. Turned on or off, you're freaking me out. PLEASE use an insulated pointer. I know you know what you are doing, but it's WAY too easy to make a mistake, and you'll only do it the once.