Old bench power supply restoration (AUL210 from 1983) part 3 

exactly :D

​@@Among_us9999 Patreons get early videos.

@@taurielv ok thx

I haer that 🤣 👍🇮🇪🙏

Why not crapacitors? 😜

…or capashitors 😅

@@kurtiunlisted8589 🤣👍👍

Big thanks ;)

I'm already working on it ;)

@@DiodeGoneWild Awesome 👍, you are one of my favourite RU-vidrs. 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 RU-vidr too. Iv learned more for Danny than any othe channel. 👍💚🇮🇪🙏

wtfffff

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?

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)

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.

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.

The capacitor is fine, it's just covered in dust.

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.

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

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.

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.

Something like this ;)

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).

It was quite common in the 1970s and 1980s. I have another power supply from 1989 and it also has the same thing.

also fun accent.... Cableeeeeeee front paneeeeeelllll machineeeeeee

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

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.

CRAPxon.😂

that stands for "zapnuto", standing for "powered on". But it sure is tempting to make some puns.!

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.

Thank you ;)