Old bench power supply restoration (AUL210 from 1983) part 2

[@zaidhussain5206]

Yes we still watching , please continue & thank you for your nice analyses .

[@johnwelbourn3811]

What a fantastic video! Watching your diagnostic thought process unfold is an education in itself. Superb. Also, there aren't many videos amongst the hundreds that I watch on KZbin that make me laugh out loud, it's added bonus content, your cat is hilarious.

[@michaelseitz8938]

Another electronics detective story. Thanks 😊 Bloody hell, even the sidekick cat makes an appearance. Awesome! 😁

[@michaelfisher9671]

I agree with your assessment about fake dirt and rust on items on restoration videos, DGW. I’ve dealt with plenty of old rusted and dirty parts and they never look so perfectly and evenly dirty as in those videos. I’ve long been suspicious but never heard anyone voicing the same view.

[@DankNoodles420]

look up fake restoration yt videos on reddit, its widely known and there is a reddit post I believe listing the fake channels... or maybe it was a youtube video that listed all the fake channels that stage their content.

[@versedbridge4007]

The guitarologist did a video on 2 of those video mill “restoration” videos, cassette deck and a guitar.

[@ivolol]

You've just not searched, Michael! Check Internet Anarchist's video, "How Restoration Videos Are Faked", 2.4M views. Backyard Ballistics also has one going over fakers' methods. Both interesting.

[@michaelfisher9671]

@@ivolol correct, I’ve never searched. Never cared enough to bother.

[@hernancoronel]

Still watching and looking forward to the next journey Daniel! Thank you for the great video!

[@Langendimi555]

You bet we are still watching! Thank you for taking us along, very nice video!

[@listerine-pr5lt]

This guy is trusted and knows what he is talking about.

[@VictronixCZ]

Velmi se mi líbí ta tyristorová předregulace. To jsem ještě u zdroje neviděl.

[@kwpctek9190]

Funny, "If anybody's still watching.." 😂You know darn well you're way too humble, so grab some of that fire extinguisher and put your feet up!👍 Watching you work is always awesome!

[@sortofsmarter]

I have learned soooooo much from watching your channel. I've watched you from 40K+ subs, and so happy for your growth. I really appreciate the honesty and the no behind the scene games for video setups, just good content, mistakes and 2nd guessing and all. Thanks for all you share..

[@oliverkykal8087]

Danke!

[@DiodeGoneWild]

thank you ;)

[@kubaneatess2384]

vcelku zajímavé srozumitelné video

[@xDR1TeK]

You just blow my mind on how easy you find your way around these boards and schematics. It takes me a while to get my bearings right. Good on you.

[@vasekdvor]

Všichni koukáme, ani nevíš jak dlouho jsem se těšil na tohle video. Když si ho vydal řekl jsem si "no konečně" 😄😄

[@German_byte]

Thanks for a very interesting video. Very satisfying to fix a device that has been faulty for a long time.

[@KeritechElectronics]

5:52 - there should be a bushing between the PCB and the meter's screw terminal. No wonder there's no contact or intermittent one. Fortunately fixed (you can see it at 6:14). I like the way of converting a vertical cap to horizontal with a piece of kapton tape. It's a nice one - gonna put it to a good use :). Nice boards, all hand routed as it was done back in the day. Now I want to make a 723 and KD503 based dual-ganged symmetrical PSU at 0...25V 0...3A, with an adjustable current limiter. That would be a nice addition to my lab, but first I'd have to think of a way to do a coupled voltage and current adjustment. I was thinking in lines of a multi-turn pot first, but I'm more and more drawn to rotary switches for coarse adjustment and a dual-ganged pot for fine. Your bridge rectifiers don't sound too full :D

[@erikziak1249]

TOP QUALITY CONTENT! Like and eagerly waiting for part 3.

[@HugforYou]

Another great vid. Thanks Dany!

[@Ale.K7]

Loving this series!

[@debin83]

Nice video.... Thanku for second part 👍🏻

[@edgeeffect]

Wow... all those old transistors.... I've got none of my childhood salvage left but I do have stuff out of the rubbish at work from 1990.

[@jamesmauer7398]

In the next video I'd be interested to see the oscillations caused by the having the full resistance of the pot in series with the capacitor!

[@tomwatson7107]

Thanks DGW, been waiting for part 2. Perfect evening viewing ❤

[@Hasitier]

We are still watching. 😀

[@joejane9977]

thanks was great fun

[@Purple431]

I found a trashed crt television and I ripped the back of it off and took out the circuit board. It was LOADED with capacitors and resistors. I now have a collection of the electrolytic caps (the biggest being my favourite)

[@Alexelectricalengineering]

I am thrilled about the next episode, nice like always, yes I am still watching till the end, thumbs up

[@pisze1973]

Cool and informative.

[@michaelfisher9671]

Really enjoying this series, keep going.

[@ondrejbursa9969]

I'm glad that I'm not the only one who managed to blow up the tester by accidentally charging a capacitor and then sticking it in :D

[@reco9607]

Yes I'm still watching ;)

[@German_byte]

Thanks

[@TheDefpom]

Yay a part 3...

[@mohalothman99]

very nice Video, looking forward the next episode about this power supply.

[@BobT36]

I love how there's a ZAP button. :D

[@amydamon2323]

Really great video. I always learn a lot from you. Keep up the good work!

[@walak89]

Great show!

[@Speeder84XL]

Very interesting! Once I saw those old potentiometers, I taught "I wonder how good those contacts are". I would say it's a poor design that the current limiting stops working because of a bad potentiometer though (if connection get poor in the potentiometer contacts, the current should drop toward zero, rather than increase uncontrollably - since that can cause damage in some cases). I know also from building preamps for my recording equipment (that I use for example for the audio on my KZbin clips) that potentiometer contacts tend to wear out or oxidize after some time. In that application it's very sensitive, since poor contacts will cause terrible noise into the audiosignal and onto the recording (even before it causes the resistance to go up significantly). So after getting way too many recordings ruined by that, I have changed to just using a rotating switch that adjusts the gain in steps thru fixed resistors, rather than having a potentiometer.

[@DiodeGoneWild]

This type of potentiometers still works well after 40 years if stored well. but this power supply wasn't stored in good conditions. It's full of dirt. It also might have been stored in a freezing garage or in an attic baking in the sun. This is why the rubber seals of the capacitors are cracking. And for audio, carbon potentiometers have to be used, not cermet.

[@Speeder84XL]

@@DiodeGoneWild Yeah, bad storage was most likely a thing here. I don't think it's so much about temperature, but humidity - that is what really causes contacts to oxidize. But still, there is always a risk of the sliding contacts lose contact - so it's good to design in a way so if that happens, the voltage and/or current drops rather than rise and risk causing damage. Also - I guess you ment the opposite. Cermet is what usually used for audio and carbon for other less sensitive applications. But still, I think I will stick to use fixed resistors for recording gear. With a camera or recorder that records 24 bit and have a low "analog" noise floor, the gain doesn't have to be adjusted that often anyway. I will soon also get a 32 bit float audio recorder as well, then the gain almost never have to be changed during a recording. If the potentiometer do fail, that noise cant be fixed afterwards. The wide spectrum noise (hiss, crackle and loud "thumps" and even bangs) that poor contacts cause, is impossible to remove afterwards, without ruining the audio quality of the recording it self. As always (according to Murphys law), this tend to happen at that perfect "once in a life time opportunity" recording. In case the gain have to be adjusted with a "stepped" volume control while the recording is ongoing, there will be an audible "step" up or down - but that's very easy to fix in post processing, without any loss in audio quality. But for playback gear, good potentiometers will do fine.

[@SatyajitRoy2048]

Very interesting

[@skyem5250]

i love your cat in these videos

[@nickd2084]

way to go, awesome. Look forward to your video drops. Thank you. From AU.

[@taharmouz8864]

I am still with you☺

[@whitesapphire5865]

I'm glad to see your little sidekick 'Meikhat' is still guiding you along. I haven't seen him in a while! That's an interesting little project you have there, and not really in my field of experience, so even more interesting in that respect. I think you'll make a 100% success out of it. It'll be interesting to see how it performs when called upon to do some work.

[@NikiBretschneider]

As far as I know the fixed voltage section does not work like a current limiter, but it has something like overcurrent fuse. If you increase the current, it goes up to 1A/2A (depending on the voltage) and then it trips and the current fall down to some hunderds of mA where it sits until the load is removed from the PSU's output. This is how it is intended to work. Calibration process of this requires variable load and is somehow tricky. Regulated voltage sections could be easily modified to behave exactly the same way. That potenciometer with failing wiper is intended to compensate oscilations of the regulation loop and it should be set right to the edge of stability, which would provide the fastest reaction of the control loop. This should be adjusted using oscilloscope observing the reaction to the rising and falling edge of the step changing load. If you have nothing, that could vary the load in steps, you can also adjust this to the point, where oscillations of the output stops and does not kick in after powering the PSU down and up, but this gives less precise adjustment making the loop to behave a little bit lazy and conservative. Adjusting this on the voltage side of regulation is similar to the current side, but the output voltage change is excited using the external cotrol port on the back of the unit. This is the easy part of it, it just requires just a pulse generator. Maybe, there is possibility to excite the current change same way using the external control port, but I didn't try doing this that way. And, as I look at the behavior of that regulated channels, you have the issue with the 120Ω instead of 100Ω wire potentiometer in the +3V continuous regulation. As I know this affects all units made by ZPA, the original Aritma units (TSZ75) did not have this issue. They was unable to obtain a 100Ω wire potentiometer, so they used 120Ω instead resulting in that the +3V position of the continuous regulation in fact adds about +3.6V, which is annoying thing, because the scale around the knob does not fit. This can be easily fixed by adding some paralel resistor with trimmer to that 120Ω potentiometer adjusting it to fit the scale at +2V position resulting to the reasonably fine corelation between the scale and the output voltage. This is an easy fix of something, that manufacturer horribly screwed past in the 80's. In fact, after fixing all faults and adjustation it is a decent PSU with an high (not precise) accuracy on the fixed voltage section, the regulated section is far less accurate, but still reasonable. These PSU's are not easy to fix, but until that huge transformer blows up, they are at least fixable. When it comes to adjusting it, this PSU is a beast, it takes a long time, but it makes sense to undergo that process.

[@hoddelkind]

Great Video!

[@debin83]

Nice video.... Thanku for second part 😂

[@lmwlmw4468]

Nice.

[@G1ZQCArtwork]

Interesting. I like vintage technology. You can fix it.

[@a.lisnenko]

It is very interesting!

[@WizardTim]

Nice! I love that thyristor circuit, never seen it before yet it's such a neat idea! I wonder why it's never used today? Maybe for the cost and complexity of driving a thyristor back then you can just instead drive a full SMPS today? I'm guessing the switching noise is probably a no go for many linear devices today? Or maybe ZPA Košíře had a patent on it or something?

[@DiodeGoneWild]

Today, most of power supplies are SMPS. Even bench power supplies tend to be SMPS, but they can have a linear regulator at the output for better regulation. The SMPS supplies just a little more voltage then the output voltage is, so the linear part doesn't dissipate much. And if a bench power supply really has to avoid the switching noise, it now uses a transformer with several taps on the secondary instead of the thyristor. The problem of the thyristor is a horrible power factor. All the current happens in a very short moment. That's why the transformer in this power supply has to be quite oversized.

[@WizardTim]

@@DiodeGoneWild Ah of course that massive current spike when the thyristor is triggered would just saturate a normal transformer for that VA, I now see why no one uses it over a smaller/cheaper transformer with multiple taps and a couple relays. I still think it's a neat idea though!

[@Basement-Science]

@@WizardTim Another big problem with these kinds of circuits (Phase-fired controllers) is that it's still just running at 50/100 Hz. You still need huge capacitors and cant feasibly get inductors to form LC filters etc. It's sort-of like an SMPS, but worse in every way. Of course back then, there were no high-voltage Transistors with reasonable gain, speed and losses etc to make an SMPS, so this was the closest you could get.

[@Speeder84XL]

@@WizardTim Saturation is not the problem, but simply increased power losses. The resistive power loss in the windings goes up with the square of the output current, while the output power only goes up linearly. So by pulling the same average power in short bursts rather than a continuous current, the power losses will go up significantly (and the shorter and higher the pulses are, the greater the power loss). Also the losses in the core of a transformer (due to eddy currents and magnetic hysteresis) goes up with the square of the frequency - and by pulling the current in short sharp bursts, there will be a lot of high frequency harmonics and noise added to the current, which will increase power losses in the core as well. But, it's still way better to use thyristors, than regulate the voltage all the way from zero up to a high voltage using only linear regulation (at low output voltages the efficiency will be extremely bad - well below 50%). So at the times before MOSFETs and IGBTs where invented, this was the best that was available. But today, a SMPS is way better. Not even noise performance is better with thyristors. There will still be a sharp high frequency spike every half AC wave, when they turn on - which causes the same issue as an SMPS can do for some sensitive applications.

[@perhansson6718]

@@Speeder84XL "There will still be a sharp high frequency spike every half AC wave, when they turn on - which causes the same issue as an SMPS can do for some sensitive applications." Infact isn't this the likely explanation for the issue seen in this video that necessitated those filter potentiometers?

[@tootsscaf]

Thanks for another great video! I've been bingewatching all your videos on the last weeks and its been super educational and sometimes really funny. Your cat didnt jump on the table this time but he always giving funny comments :-) if you want i can send you a free very nice japanese 430mhz ft480 yaesu hamradio transceiver from the '80s, broken ofcourse. 73 on5gs

[@j7ndominica051]

Cat goes behind the door for criticising the solderiiing.

[@nohandleleft]

Mr Wild, I watched all the way to the end so at least one (1) person sat through the entire video. I'd like to see you repair an HP8566B spectrum analyser next, maybe even convert the CRT to LCD - I'm not sure why though, I just think it'd be interesting.

[@d.k.9406]

Danke! Most Thanks so Far as i see XD As other Guys in their comments said: Voltage Preregulation with Relays and multiple transformer tabs is known... But never heard about thyristors as preregulation. So i'm highly interessted in the next Episode of fixing The middle section The proper oscilloscope pictures ( my oscilloscope is this well known red chinese 25€ one) And more surprises Really surprised about this faulty contact of a Potentiometer!! O.õ Second Thanks for another almost BloodY long Video ;-p

[@DiodeGoneWild]

Big thanks for your support ;) I'm glad that my effort put into these videos is appreciated and that somebody prefers long educational videos over stupid one minute useless "life hacks". The potentiometer is an open type (no cover) and quite a lot of dust and dirt got into the cabinet, so it makes sense. In a clean environment, these potentiometers tend to be reliable. I'm still using the 1980s old stock of them with no problems as long as they have been stored well.

[@d.k.9406]

@@DiodeGoneWild In every case is working long real life education better than ultrashort fake hacks Can't give support to all of your content, but havn't seen any bad videos, only some of them are to short :p Often i look your videos several times again, to squeeze out all blooddrops of information :-D (Bloody long has to be at least 30mins or so) xd How much time you have to invest for recording this videos in reference to the playtime for us? I hope not more than 2 times? Sorry my english is only groundlevel... hope you understand my request/question?

[@robertneill3057]

Put slightly better heatsinks on the heatsinked transistors. One thing to watch is the overall height as the boards are plugged in one behind the other. The collector is usually connected to the case on most metal TO18 and TO5 transistors.

[@ivolol]

Gotta love the cat tax

[@dipubiswas8520]

I also repair an age old power supply by changing faulty potentiometer

[@ZygmuntKiliszewski]

I waiting for part two, greetings 😀.

[@04ajeet75]

I am watching and I also watch the spark gap tesla coil & solid state tesla coil series and also dangerous charger series

[@Nisstyre56]

lmao at "throwing kittens into the sewer"

[@ErwinKouws]

I blew up the same component tester exactly the same way....🙃

[@rostislavhruska8601]

Tato anglictina patri do odkazu svetovych dedictvi. Posusnani.

[@_wave64_]

I used to admire those pink Tesla capacitors - they looked so more modern compared to the bare aluminum Soviet and Hungarian ones

[@DiodeGoneWild]

The ones that were stored in better conditions still work. But this power supply was probably freezing in a garage in winters, and baking under the sun during summers.

[@AdamV20]

Yes, i'm interested. I want to bulid PSU with a thyristor regulation in it

I blew the same capacitor tester like you, with charged capacitor

[@zx8401ztv]

You did well to make sense out of that madness. What a shame your "Transistor tester" had a shock, but i think you have built a far better cap/esr tester anyway....or i might be getting mixed up with your battery capacity tester. What about getting the code and an atmel chip, maybe its cheaper to get the whole tester again. I have one as well, not perfect but better than a kick up the ass lol.

[@higamitakaro]

2:25 - Does this leakage tester operates similar to Mr. Carlson's one? Do you have a video about it or it's schematic?

[@nowheremanjk8624]

4:58 jak przełączałeś lewą sekcję to trzaskało w głośniku

[@celsoneves2368]

Jewel great

I want to see oscilations on osciloscope and the middle section fixed!!!

[@tkordus]

I blowed multi tester by charged capacitor too 🙈

[@lezbriddon]

capacitors of that vintage used inert electrolytes so don't internally rot like modern water based designed to fail ones. (notice the leak has damaged the plastic cover not the metal) old capacitors would cost 5x as much due to the magic electrolyte but late 70s the new chemicals made them cheaper to make and last 'the life of the product'

[@STONEDay]

I have a vintage drum mashine from the past and would like to re-cap it. It has 0.47uf & 2.2uf 16v capacitors but I can only find 50v versions. Is that my best option? I do not have tools to test capacitors and would like to replace all them all.

[@tootsscaf]

I bought the esr series resistance capacitor tester from aliexpress which diodegonewild made a super educational video about.

[@tootsscaf]

Is it a 808 or a 909 or maybe a linndrum? Hope you can fix it because these old drum machines have a great sound. Good luck. (If not buy a behringer rd8 like me)

[@kotekxd99]

Bladi long video xDD good job

[@localgamingmaxyt7929]

❤️❤️❤️

[@PrajjalakChattopadhyay]

Please fix the constant voltage section as well. Would love to watch that.

[@Jkauppa]

try dc voltage controlled ac voltage capacitive c-cr division voltage regulation, not shunt regulation with diode full blast only

[@VictronixCZ]

Myslím, že růžová izolace na elektrolytu byla sežraná molem. Typické piliny od mola.

[@tangoalpha8381]

🇧🇷🇧🇷🇧🇷🏆🏆🏆 Nice work!!!

[@objection_your_honor]

Old Soviet part have so much character. I hate smd components because they have no character and look like braille dots.

[@koharaisevo3666]

Do you want your electronic device to cost triple so the manufacturer can use expensive process to print extremly small character on the components?

[@MC-01]

It always fascinates me how technology have gone over the years for example the MiniWare power supply is more or less 10X smaller than this and can output more power

[@dipubiswas8520]

what does the cat do.....is it your mentor......! ‌‌!!!

[@MahBor]

I'm restoring a vacuum tube signal generator from 1960s and the electrolytic and paper capacitors have leaked and are showing completely different values. Do i have to replace them or is it ok to turn on the device with the capacitors being a few percent off? I don't want to destroy the device.

[@Basement-Science]

well which is it? "completely different values" or "a few percent off"? Tolerances on components in those days were often relatively high to begin with. But if you can already see components that are clearly damaged, I would just replace them first, since there's no way of knowing how they'll behave in actual use. It's also often a good idea to limit the current/voltage going to the device when first powering it up. Limits any potential damage if something is wrong.

[@MahBor]

@@Basement-Science Thanks. Most of them are 10-15% out of spec but have no visible damage, only leakage on some. Should i replace them? A few are 300%-500% off and I'm definitely replacing those.

[@Basement-Science]

@@MahBor Do you mean 10-15% off the rated value, or off including the part's rated tolerances? Just to clarify. Probably fine keeping those either way for a first test though. A small drift in value is unlikely to cause damage to other components.

[@MahBor]

@@Basement-Science 10-15% from the rated value, and most of them have 10% tolerance so i think yeah they should be fine. Most of the ones that are up to 500% off have a tolerance of 20-25%. It's so hard to replace them because every component is bolted to the chassis and soldered with wires. Better than wire wrapping but still a mess

[@Basement-Science]

@@MahBor I can imagine. Sometimes it helps to cut the leads first, then desolder them individually.

[@uksuperrascal]

Aka Odysee - Super-Grand-Ad - LIKE 09 - Video 3 Please.

[@gordonwedman3179]

Interesting fault. Sort of an odd power supply with no voltmeters.

[@DiodeGoneWild]

Why a voltmeter? The voltage is what you set it to be ;)

[@gordonwedman3179]

@DiodeGoneWild But doesn't it have a variable pot as well? Perhaps I'm not remembering correctly.

[@thomasw6169]

Looks more like bug poop then electrolyte

[@wolfrobben6914]

Danke!

[@DiodeGoneWild]

Thank you ;)

[@andreastarp6583]

Danke!