Old bench power supply restoration (AUL210 from 1983) part 4
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- čas přidán 9. 09. 2024
- Finally fixing this vintage linear bench power supply (AUL210 made by ZPA Košíře závod Děčín in Czechoslovakia in 1983). It has two adjustable 0-36V 0.2-2A outputs with thyristor (SCR) pre-regulation, two 15V 1A outputs and one 5V 2A output. I found and repaired the problem in the faulty 15V section. I also fixed an unexpected bridge rectifier problem in the other 15V section. Some more electrolytic capacitors tested and replaced. Adjusting the feedback PID to prevent unwanted oscillations. A leaking, shorting and exploding paper capacitor in an interference filter. Some oscilloscope measurements in the thyristor controlled rectifier section that pre-regulates the voltage.
The 1st episode:
• Old bench power supply...
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That diagnosis using the sounds of the transformer buzzing was quite clever.
It's an experience who make technician work better
I’d love to know more about the science behind this, more specifically how a normal transformer functioning fine makes a 100hz hum?
@@BritishEngineer Usually the iron core transformers use laminated sheets to minimise eddy currents, and I think the varying magnetic field vibrates these sheets a little, causing the noise. The sheets are usually welded together at a few points to reduce this as well as making sure the core actually stays together. Remove these welds with an angle grinder, and your transformer will make crazy loud noises
I had the same problem with my solder station, it were also the diodes, the FBR 4 diodes.
I replaced them all, one was burned, and yeah also strange sounds from the transformer,
and i replaced all the caps with much better ones on put 2 fans in the solder station, now
everything is working normal again.
@@AmigaWolf Good repair. Glad it's working again.
I'm glad we couldn't smell that interference filter roasting. That was a very enjoyable series of videos.
Boiling, not roasting 🤓
(Im just being pedantic, please ignore 😉)
Yeah, the smell is not pleasant!
Reminds me about... EVEN MORE SAAAALT!!! 😆
@@user-ui6xt4fd1f MOARRR SAAAAAAAAAAAAAAALT!!!!!
Wow, that open pin on the connector would have had me chasing faults elsewhere for a good while... Loved the interference filter at the end, pretty sure interference filters aren't supposed to make bubbles!
Yeah, I don't think that interference filter is supposed to bubble out boiling liquid Something doesn't look right to me. I think it might be broken.
That filter was medium rare ..
just perfect!
Didn't realize that this was a cooking channel, but I hear bacon.
This has to be the most overcomplicated linear power supply I've seen. Congratulations fixing it 👏
ah i wanted to see the teardown of the sizzling interference filter :( learnt a lot from these series, keep on going!
Really enjoyed the cooking of the interference filter!
The open pin connection in the Darlington was bad enough to make the unit seem haunted, then the interference filter grenade!? Amazing!
Great testing of the interference filter; mine is always tested in the power supply while it's on. I enjoy your scientific methodologies; please keep the videos coming.
LOVED the filter in the very end - and of course super smart to use the vibration of the transformer :)
This channel is by far the most educational electronics channel I've ever seen, it's crazy how much information you know about diagnostics and repair of literally any electronics problems, genuine thanks for making such insightful and useful videos freely available for all of us to learn from :)
Wow!
The new image quality is outstanding!
The thyristor limiting is genius before SMPS.
When you tinker with electronics so much that you develop perfect pitch
Great repair and that mains filter oozing out was awesome! Your measurements were spot on. That probably caused the Trag 2 Amp fuse to blow due to excess leakage.
16:08 such feline wisdom 😅
I love repairing old stuff too, even though I have no plan for use. Can't resist the challange.
Excellent series.
Fantastic old power supply, nicely restored.
OUTSTANDING
Great to hear about regular updates on sunday. Also power supply and your diagnosis about it, is very good. Keep your work up.
Loved this vid series man. Just awesome
20:52 Nice 😀😀😂👏🏼👍🏻👍🏻🔥
Great video, thank you! Especially the explanations on the 50/100Hz hum are quite helpful to me.
Thank you for your support ;)
Nice video; interesting machine
7:20 very old semiconductors often tend to open circuit, also sometimes a short circuit occurs when the first turning on after decades of inactivity, experienced this many times.
20:51 even more salt
A uni-directional dimmer circuit for PWM pre-regulations - BRILLIANT!!!!!!!!!!! Not so great for interference, which explains the filter that surprised me! :)
There's Schaffer filters available, but they are metal cased and have push on terminals at both ends of the case. There's a 3A one from Rapid Electronics in the UK. Will be subject to the board space dimensions if a replacement is decided upon.
A tyhle překrásný odrušováky jsou třeba v osciloskopech BM5xx většinou připojený přímo k síti ještě před pojistkou :D Tyhle ohňostroje rovnou z těch přístrojů vyhazuju, možná přicházím o jejich výhody, ale rozhodně lepší než si opakovaně vydýmit místnost příšerným smradem odrušováku. Většina z nich už bývá dost načatá.
Whooooa, that'd be a RUD on that filter. Micely repaired.
Interference filter starts leaking on camera:
"Naaaaaiceeee!!!"
Appreciate everything you do on here especially your easy to understand ways of explaining electronic circuitry! 👍👍 _tom
Interesting!
And nice surprise the at the end with that interference filter spewing out boiling electrolyte, haha
It's not an electrolyte. I guess it's some oil or wax. Hopefully not PCB.
Nice ! and with a good amount of salt.....cheers.
Thanks
Thank you ;)
cookfest is real, 😁 , nice video as always!
I like yr content so so so much
The renowned Czech optics maker meOpta was once part of ZPA.
I've built my first power supply with those diodes with blue ring… must have been 1983?
That filter reminded me of a sewing machine I looked at around a year ago when visiting my wife's cousin and her husband in Germany. We had the thing in bits and were trying to figure out why it had started to run slow, accompanied by a slight smell of "hotness". While leaning over the opened base of it, the somewhat similar mains filter block decided to let me know what the cause of the issue was by exploding very loudly.
It emitted a huge cloud of acrid smoke, while showering me with hot wax and indelible brown goop from the filter capacitor (thus ruining my T shirt). For extra pyrotechnical points, the coil, which was apparently red hot, then burned a small, neat, round hole in the table cloth.
For some strange reason, I and my German host found the whole thing hysterically funny, but I'm not sure the ladies where particularly impressed.
Maybe ensure you have your eye protection on next time you boil one. Just saying. ;~)
Similarly one day I bought a studio reel to reel recorder, it was listed as "working", but also weighs over 100 kilos. And before the seller left my house I said I wanna test it. "Luckily" the filter was on the verge in a similar way, so when I plugged it in something inside exploded with a lot of smoke filling the room and the breaker tripped. At that point I didn't yet know what happened but couldn't help asking the seller if they'd rather give me a 50% discount, or carry the 100 kg beast downstairs back to their car, and they gladly accepted the former ;-)
I see a lot of wonderful Tesla component in this piece of equipment.
Fortunately they are not used very often in North America.
However these ones seem to have lasted at least 30 years.
I once bought some 60 watt Tesla light bulbs.
They lasted about 4 hours.
Lamps lasting just 4 hours? They should last much longer, unless they are special super hot filament photo lamps. Or they might have some air already leaked in.
Fucking LOL I was sat expecting that "Niiiiiice".
Awesome 👍👍👍
happy end of this series with a lot of drama between 😄
Nice!
Niiiiiiiiiceee!
aaaaaand the magic smoke was released lol
Diodes!
What an interesting series! Complex laboratory power supply, decent design for the times, nicely built, and totally fixable. Good troubleshooting. Danyk, thanks for the memories of TESLA components.
Off hand, are you familiar with early eighties Polish Meratronik V640 electronic multimeter ? Fixing one right now. Eastern European electronics is fun...
Thanks :) I don't know V640. From Meratronik, I only have the V541 voltmeter.
Creative teacher your metal detector Creative teacher your metal detector diagram 🙏
We wait impatiently
❤️❤️❤️🙏🏻🇮🇳
Gratulujem k dokončeniu opravy zdroja, nech ti pekne slúži. Ten konektor v čase 3:30 by sa podľa mňa po odvŕtaní nitov nerozpadol, ja mám takéto konektory nakúpené ako nové, len nie sú pozlátené a sú to jednotlivé kúsky po 12 pinoch (nie takto mechanicky spojených viac 12 pinových sekcií) a držia pekne pokope, používam ich do niektorých bastlov čo vyrábam, hodia sa k tým ostatným retro súčiastkam, ktoré taktiež v svojich prístrojoch používam.
Thank for the clear explanations.
I wonder where the liquid of the interference filter came from? Accumulated moisture in the interference filter?
Looks like boiling wax from the paper capacitor perhaps. Would be nice to make an autopsy video of it :p
Hola!
مرحبا استاذ كيف يمكن الحصول على مخطط كاشف المعادن بتخطيط اسهل انا مبتدئ ومتابعك تحيه طيبه
To think of what your house must smell like now. Or does it not smell so bad with the liquid escaping?
The smell disappeared after opening all windows for half an hour ;).
@@DiodeGoneWild I had one of the RIFA paper caps go off suddenly with a woosh and white cloud of smoke. Even after turning it off within 2 seconds, my room smelled for days :O It was not NIIICE. :(
When a capacitor reads low (using a multimeter) it is probably leaky.
The Multimeter reads capacitance through measuring the time constant, which gets longer when the capacitor is leaking, hence the higher capacitance reading.
In my personal opinion, if a capacitor measures more than ~10% over its nominal value, its probably bad.
Electrolytic capacitors usually have a tolerance of +/-20%, so 10% high is perfectly fine. Vintage electrolytic capacitors sometimes had weird tolerances, like -10/+80% for big filter caps, so almost double the nominal value is fine in the case of some vintage capacitors. They done this for reservoir caps, for two main reasons: they intentionally made it higher capacitance, so it will have more headroom for aging, and also for ease of manufacturing, they probably aimed for +50% of the nominal value, but whatever came out, was most likely in the -10/+80% tolerance range, so they rejected only the really bad ones, which caused a better yield, less production loss.
If excessive leakage current is a concern, it should be measured with a current meter, after the capacitor is precharged to its nominal working voltage.
Cooking emi filter
🌟🌟🌟🌟🌟
17:35 windows
Can anyone please point me to the explanation what is ring testing and what does the ring testing (red device) with the LED counter do? Google searches seem to point me to something completely different.
The “ring” tester measures the Q factor of an LC circuit by counting the number of oscillations (“ringing”) after one initial impulse. The higher the number, the less lossy (i.e. less resistive) it is.
@@noneofyerbeeswax8194 thanks thats a very elegant and concise explanation! So I suppose you would ring-test a circuit to see if there are unwanted oscillations in this case.
@@yaksvk Well, in this case 20:20 you actually WANT a high number (tens) of rings. The ‘5’ here may indicate one of the following:
1) Shorted turns in the inductor (low inductance = low Q)
2) High series resistance (bad contact or really thin wire)
3) Relatively low resistance in parallel with the LC circuit - which is indeed the case here. As we know, a paper capacitor arced over and turned into some sort of carbon resistor with ill-defined parameters. :)
The main use of this tester is finding faulty components like these. A good transformer or inductor should ring a lot when triggered by a single pulse, but if there are shorted turns or leakage, the oscillation shuts down quickly. You could use an oscilloscope for the same purpose, but having it all in a small box is more convenient of course.
@@noneofyerbeeswax8194 this is like a year's worth of school knowledge condensed in that comment! Thanks!
@@yaksvk 😊You’re flattering me.
If you want to ask some more questions, you’re welcome.
This power supply has wiers more than a washing machine
I virtually could smell this czcams.com/video/bWxS2njU-JI/video.html stench halfway round the planet. Ugh.
Why not just throw it all in the dump. It looks a mess.
So what you are telling us is that Tesla components tend to fail after 30 years. Hmm, OK
Paper capacitors of all makers tend to fail after 30 years ;).
....NIIIIIICE! :)
is that a interferance filter or is some mustard gas bomb inside?