Old bench power supply restoration (AUL210 from 1983) part 3
ฝัง
- เผยแพร่เมื่อ 2 ต.ค. 2024
- Another episode of the repair journey of 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. Replacing the mains cable and some paper capacitors, testing the ESR of electrolytic capacitors. Trying to find the problem in the 15V section. How to test resistors, diodes, potentiometers, capacitors and transistors using a multimeter.
The 1st episode:
• Old bench power supply...
The 4th episode:
• Old bench power supply...
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For a hoarder of technical items, there is nothing so satisfying as finding that you have amongst all your junk the exact things you need to fix something perfectly.
exactly :D
@@Among_us9999 Patreons get early videos.
@@taurielv ok thx
I haer that 🤣
👍🇮🇪🙏
One of the few channels that I can watch whole video, listen to you and not get bored. Great work. Can't wait for part 4!
I love your all videos and watching regularly around 6 or 7 Years 🙏🏻❤️ Love from India 🇮🇳
Big thanks ;)
Sorry to make a crappy joke but maybe the proper name for the dodgy paper caps could be "capoocitors"
Why not crapacitors? 😜
…or capashitors 😅
@@kurtiunlisted8589 🤣👍👍
I want episode 4 right now it's so awesome 😎👍👍👍👍
I'm already working on it ;)
@@DiodeGoneWild Awesome 👍, you are one of my favourite TH-camrs. Som time ago I was having trouble with my power supply UTP3303, it was only dirty contacts in the switches I only need a little bit of contact cleaner. I playing with electronics for more then a decade, so I really enjoy your videos!!
My favorite electronics TH-camr too. Iv learned more for Danny than any othe channel. 👍💚🇮🇪🙏
I always wondered if they sued the car company Tesla … It turns out - they did (full article on Wikipedia)
The company (the Czech TESLA as on the capacitors) name survived as Tesla a.s., a private company whose shares trade on the Prague stock exchange. Tesla a.s. manufactures of radio and security equipment for military and commercial use.[3] Tesla a.s. took a series of legal cases against the American company Tesla, Inc. (formerly Tesla Motors, Inc.), resulting in an agreement in October 2010, establishing a coexistence of Tesla trademarks and regulating relationships between the two companies
wtfffff
Since A2 and A3 have identical 15V1A control circuitry on Board A, why not scope them and compare to see if both get the same reading?
I would start at 1mA load and go up from there and see is both work the same, until cut off?
I assume you did switch the boards B around to check any problems with the bus connectors controlled by board A. You marked them blue and red so as to not switch them around. I think you should and see if the problem moves or goes away.
Always possible the person making repairs put a wrong part too.
Most enjoyable. I am about to watch again as your voice has an euphoric affect. I guess the alternatives would call it AMSR, nonetheless it does have a soothing and relaxing component. People are probably thinking I am a weirdo but I don't care I like to comment how some of your videos do have the AMSR quality. This series on repairing the power supply is excellent and I am learning valuable information on troubleshooting methods, measuring techniques and interpreting the measurement values.
This is probably one of the best restoration series on platform
I know the problem. It needs more salt! EVEN MORE SALT!
You could test the assumed bad chip in the working 15V section, see if the section stops working. Then you know it's the chip.
You could also try the good chip in the non-working 15V section, see if it makes it work. But it's better to test the bad chip in the good section: you risk damaging the good chip if it's another problem in the bad section that fried the chip in the first place.
Dear Danny. The chip can be tested with 2 methods:
1 using a multimeter by competing the values with the working 15v section. If this method does not help then option 2 will probably
2 swap the suspected chip from the faulty 15v to the working 15v section and then U will see if there's some difference...
Ooo and option 3 find a same component and replace it.
GLHF
For the final problem here I am thinking that whoever did replace those transistors may have soldered them in the wrong position, and the only way to detect this is by comparing every measurement taken to the corresponding in the 15v section that works fine. This is easier to do here because they are in the exact same layout so no need to be constantly checking how should you measure components to expect the same values.
am addicted to your videos
2:47 “the ground one is just about to fall off”
2:50 * ground wire falls off *
Peak foresight
That's foresight, not hindsight!
@@ProdigalPorcupine You are correct. I must have been tired writing this. Edited.
I thought he he gave it a little tug to finish it off.
@@eDoc2020 Did something just fly over your head?
*I love your videos ❤️❤️🙏🏻👍🏻🔥👏🏼*
For some reason I I'm thinking that it's something to do with the current limit in the 15V "A" section, so my guess is something wrong with the potentiometer or how it's getting connection, since everything else seems to be working right and it's behaving like it has a really low current limit set. Thanks for the informative videos! I had to laugh when you said "half a litre of contact cleaner" and "environmental disaster" (though nothing will compare to 'more salt' from years ago :p)
please link that salt video
The LM723 can fail in this exact way. It's probably the IC that's bad.
@@kruskotv1311 I probably can't directly link, since most times comments with URLs get filtered on YT, but the video is DiodeGoneWild's Suicide Water Heater & Deadly Experiments (Gone Too Far)
That MAA723 ics should be replaceable by LM723 types, you may find the ones in metallic cans around the internet.
the thing is, MAA723 is a jellybean part here. They are really common in old gear.
New LM723 in a DIP package (uA723) cost less than 0,50€ and metal one cost 13€ new
@@odindimartino597 old surplus MAA723 costs just around 30 CZK. Not a big deal.
waiting for part 4, I can only imagine something like a broken trace leading to high impedance at the output or something. What I would do is interchange both control chips from both sections A and B to try to isolate if the control chip is bad, in that case, the problem would swap between the sections. Problem is, can you replace that (and do you have any other) control chip? I always get very frustrated when diagnosing a problem and trace down the problem to be an irreplaceable IC.
uA723 is very common linear voltage regulator surely available in DIL package. DGW surely have them somewhere in shed.
I have some spare MAA723, but I was afraid the board would fall apart if I try to desolder it :D. The traces on this board very easily come off. So I'm trying everything else first. Trying to replace the chip would be the last resort.
@@DiodeGoneWild tak výměna pak není velký problém, když je vyloženě vadný IO, tak ho vycvakáš ven a vypájíš pin po pinu.
considering that both 15V circuits are pretty much the same and have the same current capacity what you can do is replace the A2 and A3 chips with eachother. If it really is just a faulty chip then that will show that the other side is gonna go dead while giving you back that one which is faulty right now.
It might be a good idea to wear rubber gloves while handling dried out poop resin capacitors.😅
26:15 It might just be dust, but that square ceramic capacitor (?) below the IC looks a bit sketchy to me.
I have seen faults caused by bad ceramic caps multiple times, although those were always SMT ones.
The capacitor is fine, it's just covered in dust.
one best electronic eng. teacher in the world 👌
Great video DGW. It is a bit spooky that your wonderful cat can predict which videos will trigger my ASMR
Its funny how some old components lasted a lot longer than their modern counterparts, while others are complete junk vs their modern counterparts
Linus needs to send you a screwdriver.
Fascinating series, thank you!
I love your channel! Great videos! Thank you for this great explanations!! 👏☺
Great Video as always!
I have a suspicion that its either a high series resitance in the old cables, connections or a problem with the current feedback but thats probably inside the control chip so not much hope :(
But there are two 15 Volt Sections so you could swap or check the other, no? And you could try probing closer to the components to get a better idea of a potential voltage drop or oscillation that doesnot show in the output voltage or something else.
Anyways those are just some ideas from me, but surely he knows how to fix it already, right?
I remember having a similar problem on a linear power supply based on an L123 linear voltage regulator, from de datasheet of those maa723 seems almost the same chip.
In my case the transistor used to sens the current (pin 10 Base and 1 Emitter in your case) was shorted, so the current capability was reduced only to the current capability of the buildt in opamp, i was able to still use the broken ic just disconecting the pin used from the shorted transistor and replicating the circuit outside! (the collector of the new current sensing transistor has been connected to the output of the opamp before the series pass transistor on the output, pin 9 in your case).
Maybe is the same fault 😬(or maybe is the buildt in series transistor)
Great video as usual 💪
Yes, this MAA723 is the Czechoslovakian variant of the LM723, uA723. And yes, it quite often fails in this way (all brands of it). An other blogger reported that the current limit transistor failed in his LM723s in his DIY lab power supply, as soon as he powered any CB radios with it and pushed the TX key. No matter what kind of common or differential mode LC filtering trickery he tried, after frying a dozen chips, he figured he will just use an other power supply for CB radios.
Getting better and better :-D
Pity it didn't have caster wheels to make it easy to move.
It's too easy to damage your back by lifting heavy equipment.
Well, i think you'll probably swap the regulators of the two 15V lines to see if the problem move with them.
Not a good idea to unnecessarily swap components in this type of board. The copper laminate fells off from whispering the word "heat" too close to it.
@@mrnmrn1 He knows how to bodge them eventually
Please , we need new lessons about new switching technology exp ( PFC , PUSHPULL WE DEAT TIME FEED BACK,..FLYBACK, .....), thanx teacher
Happy to see you are using your new multimeter.
Can’t wait for episode 4! 😉
Ďalší diel z veľmi peknej série, je mi sympatická táto stará technika. V čase 26:00 som si všimol jeden nepekný studeňák na spoji, ktorý vedie na jeden z vývodov MAA723 (myslím že vývod bázy tranzistora V19), ale v ďaších sekundách z videa (26:05) som si všimol, že si ho opravil, takže nemám tušenie čo ďalšie okrem vadného IO môže spôsobovať túto závadu. Ale chcem poďakovať za túto sériu a budem sa tešiť na ďalší diel.
Studeňák to nebol, vývod bol zoxidovaný, takže to nechytilo... Studeňák sa nazýva spoj, ktorý bol bol spájkovaný nízkou teplotou alebo príliš vysokou, t.j. zvráskavie. Ale zoxidovaný vývod proste nemôže chytiť...
@@heno_3098 Aha, tak to som si splietol pojmy, ospravedlňujem sa za chybnú informáciu.
its a little easier with discrete components and a schematic. Sketch out what voltage you expect, and measure it.
I like your ring tester!
I think it's a current setting trimmpot. I've seen those go open ( wiper contact).
Glad to see you here! You are right, these TP011 can be a bit of pain sometimes. On older, more cheap carbon layer TP042 trimpots, the wiper would just break off entirely.
What is the name of the oscilloscope that you were using at the end of the video?
Is it good enough for a hobbyist?
Can anyone tell me if you can use a synchroscope for aligning two gas/petrol generators frequency together??? ANYONE PLEASE??? THANKS.👍🇮🇪🙏
Wow, you really lucked out finding that power cord socket. Is that a common part in your part of the world?
It was quite common in the 1970s and 1980s. I have another power supply from 1989 and it also has the same thing.
Danke!
Thanks!
As always.. waiting for your next upload.
The lamps look like what we call standard post office lamps as commonly used in telephone exchange equipment (in the U.K. nearly all the telephone companies were taken over by the publicly owned General Post Office). There are special tools for removing the lamps. The tool goes in the front, grabs the lamp, and then you pull it out, hopefully along with the lamp. The poor man’s tool, is a suitable piece of cable sheath or insulation of just the right size.
Hey, I'd go with a typical IEC C13 type socket, no special cables - unless you're about vintage restoration with time-original parts.
Beautiful 68n 1kV Tesla caps - I want them in my amplifiers! The only disadvantage is no marking for the outside foil, but Paul Carlson has a method of testing that. Nice paper cap teardown. We called these "potato caps".
I like the cermet trimpots on the board. A sign of good quality.
You are kidding. Those caps was first things, that went wrong in any Tesla device. Their were ubiquitous in Czechoslovakia, you could hardly replace them because other types was hardly available back then in 80'.
I think worrying about "outside foil" is a waist of time. The modern capacitors are much smaller so there is much less area to pick up noise. The tracers on the board or wires will be picking up much more noise than the "outside foil". In this case tiny amounts of rf noise is not a problem anyway.
I suspect that the original paper caps were marked with an outside foil for ground safety. I have seen the surface of many paper caps degrades and if you put a voltage on the outside foil it could perhaps, be slightly more dangerous than a ground on the "outside foil". in one case I found, the external wax coating was eaten by vermin, so it was potentially dangerous, and connected the "wrong way". In this vid the insulating case had cracked so it is more likely voltage could conduct to other components, the instrument case or a person poking at it if the "outside foil" was hot.
In the video at about 4:35 it looks like the markings for "outside foil" are opposite on each one. So likely from the factory one was put in the "wrong way". Many such cases of them being the "wrong way" occur from the factory because it doesn't matter most of the time.
Old electronics picks up a little rf noise, it is just the way it is made and the amount of rf noise in the modern environment.
@@tiborbogi7457 hey, thanks for the heads up! The cracking paper caps were obviously shit, but I wouldn't expect foil caps to fail that easily. I mistakenly placed them in the ranks of these yellow cyllinder Western made MKT caps or something, haha!
@@ccdimage I mainly meant the audio interference in vacuum tube amplifiers with typical input impedance of 470k...1MΩ. Shielding such high impedance wires and parts definitely helps against hum and noise pickup. So, the outside foil acted as a shield of sorts and was always connected to the lower impedance side, like previous stage's anode. In modern electronics we rarely use such high impedances.
IEC C13 is a bit bigger and it would require cutting a bigger hole in the metal. And of course I prefer original parts ;). I only use modern parts if there's no other option (for example electrolytic capacitors).
The MAA723 is probably a variant of the LM723/uA723
Wow, the modular design back then is so good! Just pop out that board and work on it. If that was a modern power supply it would not be easy to repair it. Great job!
I suggest replace all elec caps, either it registered good in multimeters or esr meter. They're from the 80s, around 40 yrs old
I wonder why the red lamp for that section doesn't light up when it cuts the output
Dodgy contacts on main power transistor socket?
Something like this ;)
Great work
LOL 4:35 12:20
and 5:13 "non papeeerr" lol the disappointment and annoyance in that one
Niiice. :D
I have a huge Farnell PSU that I need to blow the dust off one day.
I suspect some bad contact between the pins of the board and the terminals.
Oh man, where does that dude come from? I always have to think of a remote oasis in the desert.
Hope episode 4 will be the climax!!!🤩
Contact cleaner fixes everything
That capacitor is reminiscent of the Rifa capacitors that blight many vintage "western" electronics and electricals, usually in power supplies, cos they will go bang and stink up the place, cos they're crap, I had one fail in a Hoover Junior U1104 I had (used for noise suppression across the motor brushes), and that stink never left that vacuum even after cleaning it... :S
All paper capacitors are like that. Before the 1960s they were everywhere in Western electronics, Rifa were just the last ones in common use. Though I think the stink is particular to Rifa. I had an across the line paper cap go bang on me and it didn't smell.
Either that or it already cracked in half and something else went bang near it.
Většina vlhkosti se do kondenzátoru dostane až po jeho popraskání.
sides exploded on the poop-resin type of capacitor
It's not exploded, it just expanded as it absorbed moisture... But of course, these capacitors connected to a low impedance voltage source do explode.
@@DiodeGoneWild I mean my sides exploded with laughter :D
I spit my drink out when you said poop capacitors... and then kept using that therm again and again!
CRAPxon.😂
Will there be season 2 of aul 210 restoration series? :)
Hey, just to you know, your inverter welding machine project already reach Brazil. Also Great channel!
also fun accent.... Cableeeeeeee front paneeeeeelllll machineeeeeee
This thing is made to be serviceable forever
Cool very good.
Excited for the next part :)
Diode my man, how are you doing ?
Tf kind of accent do u have? 😆😆
don't use any spray upside down !
Cliffhanger!
13:09 I like that the Power Button is labelled "ZAP".
that stands for "zapnuto", standing for "powered on". But it sure is tempting to make some puns.!
3:25 GOLD!
3:41 Very nice!
Amazing!
ASMR to akurat mam jak widzę stare papierowe kondensatory zwijane ;}
Poop capacitors 😂
15:05 LOL
Thanks
Thanks!
Why do different types of capacitor exist: paper, ceramic, polyester, elctrolytic? What would happen if the wrong kind was connected?
Short answer, things can go boom. The different types each have their own advantages and disadvantages. Electrolytics have large capacity but can dry out and most are polarized. Regular ceramics are cheap and small but suffer from nonlinearities. Paper caps go rotten over time and are nowadays replaced by plastic. Plastic film caps don't suffer from any of these problems but for large capacities are large and expensive.
There are also other types like mica, tantalum, EDLC, etc.
❤
Thanks!
Thank you ;)
👍