Well done! Glad to see you got the original PSU working. It would have almost been a shame to have to replace it with a SMPS. When you charged the "new" capacitor and it took so long to discharge (~28:25) , maybe that's why they had the bleed resistor on the old one, not for safety, but to make sure the PSU actually stopped powering the motherboard once it was shut off.
Glad you got the original PSU going. Surprised the board took that much damage under the cap and it didn't blow out a regulator, diode, or smoke the transformer windings.
Nice work, as always! Just a tip on reforming - because you had the current limit set to a safe 5mA, you could then set the voltage to the maximum, 30VDC and let the supply automatically ramp the voltage up as the cap slowly charges. Once it reaches 30V, the supply will automatically switch back to constant voltage mode to finish the reforming at max DC. If you want to set the ramp speed, you can adjust the current. The general formula is: i * t = C * V, where "i" is current, "t" is seconds, "C" is Farads, and "V" is voltage. Solving for t in this case, t = C * V / i, or 18mF * 30V / 5mA = 108 seconds. That is for an Ideal cap, of course. Leakage or reforming will take longer, or for ever!
I'm glad the original PSU is operational and I was quite surprised that the carbon mess wasn't through the board. As I said in a comment on your last video, I had seen worse damage caused by actual shorts and burn ups. Those voltage regulators and heat sinks can be put together incorrectly. Back when I was repairing linear power supplies, someone in manufacturing forced the two together on a bunch of power supplies. When I powered up the first one, there was a dead short across the power and ground that not only blew the regulators off the board but also the electrolytic capacitors as well! As you can imagine, I was quite gun shy about powering up the power supplies afterwards and my coworkers used to play tricks on me when I was assigned them for repairs.
35:10 "I'm actually shocked!" may not be the best phrase when working around a sketchy power supply heheh! Amazing work in any case, though! I love to see the attempt of saving the original power supply nonetheless.
I'm really glad to see that you at least tried to restore the original power supply. Particularly for a device like this that's so rare, it really is good to try to preserve as much of it as possible in as close condition to the original form as you can. I'm pretty sure that what happened with that charred corner of the board is just that the capacitor blew out, which caused its electrolyte to vaporize and leave at high pressure out the bottom. Capacitor electrolytes can be highly flammable, so the escaping jet stream probably arced and caught on fire outside the capacitor, so you then had essentially a mini blow torch of high-pressure flame going through any openings on the board to the other side, and then out, charring the back side of the board as it spread out and escaped.
11:52 because the capacitor was probably charging up, especially with that large size it was /hungry/ (unless it's bad, of course) [posting before watching further]
Would be really tempted to paint on some solder mask between the traces on the bottom of the board. At the low voltages the air gap is probably fine But all that solder with such narrow gaps has me concerned that shorts could happen
I really, really enjoy your content. Your level of dedication in your repairs, showing in detail how everything works, is something I truly value. Keep it going!
Wow, that level of board damage reminds me of the testing reported by Sandia Labs in their RUclips series "Always Never" about the safety and reliability of the systems controlling nuclear weapons. One of their discoveries was that electronics can do very strange and unexpected things when exposed to fire and other adverse environments. I wonder if that board is now electrically conductive? 🤔🤷♂
Another option instead of using another switch mode power supply if you did need to replace the original PSU would be to just use a small boost regulator on the 12V rail of the modern power supply (assuming the current isn’t too high).
Εξαιρετική δουλειά ως συνήθως, αυτός ο τεράστιος πυκνωτής θα εκανε μεγάλο μπαμ αν έσκαγε αλλά μάλλον εβγαλε τα υγρά του στο περιβάλλον κ έκανε τη ζημιά αυτή. Ο καινούργιος μπλέ που έβαλες φαίνεται κ να είναι σωστό σε λειτουργία κ είναι πιο όμορφος απ τον παλιό ίσως να έφτιαχνες μια μικρή βάση εκεί για να κάθεται όμορφα στην πλακέτα? Περιμένω με αγωνία το επόμενο μέρος της σειράς, Χαιρετίσματα απ την Ελλάδα!
Nice work. Glad to see that you were able to save the original PSU. How about an autopsy of the failed capacitor? Maybe we'll find out what exactly is causing the short.
I have an old VGA lcd pc monitor i suspect needs some new capacitors. When it has been off for some hours, it shows RGBW bars trying to start, then it shows the logo trying to start, but when it finally turns on, it works perfectly. I don't have the equipment or know how to fix it, so I bought a new one.
They're the first soldiers to die out in any electronic products after the battery of course. They're very similar to a battery. After 20 years old, sitting in a drawer unused they still can't work like new fresh ones. Just like trying to charge dead battery, the ancient or tired from use Electrolytic capacitor (specifically) refuses to recharge anymore and just heats up and can cause other components to burn up. They operate by a wet chemical reaction. Those chemicals age out and become no good anymore just like old beer. Not poison but not good drinking anymore.
I have witnessed when electrolytic capacitors leak, that conductive electrolyte can short out systems and cause a lot of problems. My bet is that electrolytic leaked onto the board and cause a short circuit that then burned the PCB. If that is just a two layer (top/bottom) PCB you can cut or grind the PCB material away and rebuild it with off the shelf PCB repair stuff (like epoxy or some such), and then run copper tape "traces" to fix the PCB permanently. Had to learn how to do this at a previous job. Because we supported equipment that you may or may not be able to get replacement parts in a timely fashion. So we had to learn how to rebuild a PCB.
I'll get no price for this, but a shorted cap was my immediate thought when I saw the burned PCB. I can't see anything else causing this. Congrats on getting it back though. Did you replace the thermal compound on the linear regulator? Looking forward to part 3.
I wonder if the terminal got plugged in for testing decades later without letting that big capacitor reform correctly and the heat from the sudden current draw shorted it out through a c.ascade of fusing plates? 🤔
As always EXCELLENT Adrian one question - I am scared to power mine up. Could using a DIM BULB tester be a way to power up and not BLOW UP on me? Does anyone use one of these? I am still not brave enough to power it on.
@25:49 you its a really good thing that cap wasn't charge or you might be missing some fingers. Like a gun you should always treat capacitors as if they are loaded. you should show people the proper way to discharge caps to be clear. I know you most likely drained before filming but complacency is the bringer of workplace chaos.
Great, I really wanted to know if that capacitor was blown. So it was. I've seen smaller ones blowing holes in PCB's but they ran at higher volts inside an old switching PSU. Those where only 10 uF 450Volt capacitors. Imagine what a 15000 uF capacitor can do to your PCB.
Well, you could leave in on the side of the road in Asia so that some guy can restore it to original in his backyard with a garden hose and a toothbrush.
people are too quick to 'condemn' old power supplies, in most cases they can be resurrected and then work perfectly ok and safely, they knew what they were doing when they were designed, and are not usually device killers...., i'd likely trust an old original psu rather than some modern, possibly cheapened thing
First off, I love your videos, but... please, please cut the "reforming" nonsense and buy a new cap if you really care for the CRT. Even expensive caps like these cost far less than good CRTs these days.
Could you please deactivate the auto-translation of video titles? Sometimes I don't know what the video is about 😅, and most of the time these titles are at least cringe-worthy...
I mute his videos He suffers from “grade school student trying to meet word count requirements syndrome” and it drives me up the wall. Video enjoyment goes up exponentially when muted.
@@unfies true, his 9 minute "intro" could have been easily done in less 30 seconds... "Let's try to repair this board but if I can't we will use this switching power supply instead, let's get started"
@ the shots of the boards and parts are good enough to know what’s going on and most diagnostic stuff flows in same flow charts. No CC needed. A testament to his high polish video production.
@ very true. And much of his diagnostic work is repeating what has already been stated. A > B (explains why A leads to B) > C (explains A and B again) > D (explains A and B again). I kinda think he’s treating all of his videos as very basic introductions to electronics repair lessons (teaching via repetition in particular).
Well done! Glad to see you got the original PSU working. It would have almost been a shame to have to replace it with a SMPS. When you charged the "new" capacitor and it took so long to discharge (~28:25) , maybe that's why they had the bleed resistor on the old one, not for safety, but to make sure the PSU actually stopped powering the motherboard once it was shut off.
Glad you got the original PSU going. Surprised the board took that much damage under the cap and it didn't blow out a regulator, diode, or smoke the transformer windings.
Nice work, as always! Just a tip on reforming - because you had the current limit set to a safe 5mA, you could then set the voltage to the maximum, 30VDC and let the supply automatically ramp the voltage up as the cap slowly charges. Once it reaches 30V, the supply will automatically switch back to constant voltage mode to finish the reforming at max DC.
If you want to set the ramp speed, you can adjust the current. The general formula is:
i * t = C * V, where "i" is current, "t" is seconds, "C" is Farads, and "V" is voltage.
Solving for t in this case, t = C * V / i, or 18mF * 30V / 5mA = 108 seconds. That is for an Ideal cap, of course. Leakage or reforming will take longer, or for ever!
an 'easier' way is to reform from a fixed voltage supply at working volts, but limit current using a filament bulb...
I'm glad the original PSU is operational and I was quite surprised that the carbon mess wasn't through the board. As I said in a comment on your last video, I had seen worse damage caused by actual shorts and burn ups.
Those voltage regulators and heat sinks can be put together incorrectly. Back when I was repairing linear power supplies, someone in manufacturing forced the two together on a bunch of power supplies. When I powered up the first one, there was a dead short across the power and ground that not only blew the regulators off the board but also the electrolytic capacitors as well! As you can imagine, I was quite gun shy about powering up the power supplies afterwards and my coworkers used to play tricks on me when I was assigned them for repairs.
Those MR diodes in the bridge are sort of like fuses, when the get hot the ceramic pill of the diode just falls away from the leads
Those are cool looking diodes
"see the exploded drawing" ... how prophetic
35:10 "I'm actually shocked!" may not be the best phrase when working around a sketchy power supply heheh! Amazing work in any case, though! I love to see the attempt of saving the original power supply nonetheless.
I'm really glad to see that you at least tried to restore the original power supply. Particularly for a device like this that's so rare, it really is good to try to preserve as much of it as possible in as close condition to the original form as you can.
I'm pretty sure that what happened with that charred corner of the board is just that the capacitor blew out, which caused its electrolyte to vaporize and leave at high pressure out the bottom. Capacitor electrolytes can be highly flammable, so the escaping jet stream probably arced and caught on fire outside the capacitor, so you then had essentially a mini blow torch of high-pressure flame going through any openings on the board to the other side, and then out, charring the back side of the board as it spread out and escaped.
Excellent! so much more interesting then just popping in a new power supply.
1:20 - My 2 cents: Power up the board with bench supplies to see if it even works! I'm guessing many ICs may have been frapped during that flash-over!
Brilliant Adrian as usual 😅
Great work!
11:52 because the capacitor was probably charging up, especially with that large size it was /hungry/ (unless it's bad, of course)
[posting before watching further]
Would be really tempted to paint on some solder mask between the traces on the bottom of the board. At the low voltages the air gap is probably fine But all that solder with such narrow gaps has me concerned that shorts could happen
Red locktight needs a bit of heat, but I guess you don't want too much heat on a Cap.
Melt off the tiny connection under the rubber seal. Also it can further dry out the already drying electrolyte making it even less worthwhile.
Soroc is an evil 80s action movie villain
This is a great series, really enjoying it!
Putting that red loctite on the capacitor did seem a bit OTT.
That large cap reminds me of the single cap in an Atlas Desktop power supply. It was huge.
I really, really enjoy your content. Your level of dedication in your repairs, showing in detail how everything works, is something I truly value. Keep it going!
Wow, that level of board damage reminds me of the testing reported by Sandia Labs in their RUclips series "Always Never" about the safety and reliability of the systems controlling nuclear weapons. One of their discoveries was that electronics can do very strange and unexpected things when exposed to fire and other adverse environments. I wonder if that board is now electrically conductive? 🤔🤷♂
There is a PACE video from the 70/80's that shows rebuilding a PCB with heavy damage. It might be a good idea to review that.
ruclips.net/video/HKX-GBe_lUI/видео.html Interesting...
Another option instead of using another switch mode power supply if you did need to replace the original PSU would be to just use a small boost regulator on the 12V rail of the modern power supply (assuming the current isn’t too high).
Εξαιρετική δουλειά ως συνήθως, αυτός ο τεράστιος πυκνωτής θα εκανε μεγάλο μπαμ αν έσκαγε αλλά μάλλον εβγαλε τα υγρά του στο περιβάλλον κ έκανε τη ζημιά αυτή. Ο καινούργιος μπλέ που έβαλες φαίνεται κ να είναι σωστό σε λειτουργία κ είναι πιο όμορφος απ τον παλιό ίσως να έφτιαχνες μια μικρή βάση εκεί για να κάθεται όμορφα στην πλακέτα?
Περιμένω με αγωνία το επόμενο μέρος της σειράς, Χαιρετίσματα απ την Ελλάδα!
It's all Greek to me.
i remember the ads for this unit when i was little was fun times growing up in the early puter era :)
Awesome JOB !
"Absolutely Good Enough" - I'm making a t-shirt.
Hohoho... so lucky it was just the capacitor. I have high hopes this thing lives!
Nice work. Glad to see that you were able to save the original PSU.
How about an autopsy of the failed capacitor? Maybe we'll find out what exactly is causing the short.
I have an old VGA lcd pc monitor i suspect needs some new capacitors. When it has been off for some hours, it shows RGBW bars trying to start, then it shows the logo trying to start, but when it finally turns on, it works perfectly. I don't have the equipment or know how to fix it, so I bought a new one.
They're the first soldiers to die out in any electronic products after the battery of course.
They're very similar to a battery.
After 20 years old, sitting in a drawer unused they still can't work like new fresh ones.
Just like trying to charge dead battery, the ancient or tired from use Electrolytic capacitor (specifically) refuses to recharge anymore and just heats up and can cause other components to burn up.
They operate by a wet chemical reaction. Those chemicals age out and become no good anymore just like old beer. Not poison but not good drinking anymore.
I have witnessed when electrolytic capacitors leak, that conductive electrolyte can short out systems and cause a lot of problems. My bet is that electrolytic leaked onto the board and cause a short circuit that then burned the PCB.
If that is just a two layer (top/bottom) PCB you can cut or grind the PCB material away and rebuild it with off the shelf PCB repair stuff (like epoxy or some such), and then run copper tape "traces" to fix the PCB permanently. Had to learn how to do this at a previous job. Because we supported equipment that you may or may not be able to get replacement parts in a timely fashion. So we had to learn how to rebuild a PCB.
That PCB section likely burned up from the electrolytic cap leaking electrolyte, shorting out the PCB chemically, burning it up
I'll get no price for this, but a shorted cap was my immediate thought when I saw the burned PCB. I can't see anything else causing this. Congrats on getting it back though. Did you replace the thermal compound on the linear regulator? Looking forward to part 3.
I wonder if the terminal got plugged in for testing decades later without letting that big capacitor reform correctly and the heat from the sudden current draw shorted it out through a c.ascade of fusing plates? 🤔
Me also, its always old electrolytics.. Great series..
Awesome!
As always EXCELLENT Adrian one question - I am scared to power mine up. Could using a DIM BULB tester be a way to power up and not BLOW UP on me? Does anyone use one of these? I am still not brave enough to power it on.
@25:49 you its a really good thing that cap wasn't charge or you might be missing some fingers. Like a gun you should always treat capacitors as if they are loaded. you should show people the proper way to discharge caps to be clear. I know you most likely drained before filming but complacency is the bringer of workplace chaos.
Great, I really wanted to know if that capacitor was blown. So it was. I've seen smaller ones blowing holes in PCB's but they ran at higher volts inside an old switching PSU. Those where only 10 uF 450Volt capacitors. Imagine what a 15000 uF capacitor can do to your PCB.
Well, you could leave in on the side of the road in Asia so that some guy can restore it to original in his backyard with a garden hose and a toothbrush.
Nice!
you should remove the burnt PCB, it's like a resistor so it will continue draw current and burn even more. and short the supply.
REd loctote loosens easily with heat from the slodering iron for example.
you would want to grind away the char. the carbon is conductive even to lower volts.
Who here clapped their hands when Adrian turned on the power switch to the transformer?
Please, dont let YT autotranslate your titles...
Your channel is one of the few that really enjoys the quality of content. Keep it up!🤔🐗🌪
when things break, power supply is the one thing i absolutely don't care to be period correct. more stability and reliability, less heat and weight
people are too quick to 'condemn' old power supplies, in most cases they can be resurrected and then work perfectly ok and safely, they knew what they were doing when they were designed, and are not usually device killers...., i'd likely trust an old original psu rather than some modern, possibly cheapened thing
Except in the case of potted Commodore or Atari PSUs.
the voltages from a tranformer wont increase that much with no load , doubt if more than 20% according to datasheets i've seen,
Heat will stop red loctite from working
Isn’t Soroc one of the Simpsons aliens?
It's alive. Now wash your hands. :)
Haha I was mostly checked to just touch a random connector and get that nasty junk on my fingers LOLOL
For the love of god please install crowbar protection as linear regulators fail high ....
Messy Kweznuz Adrain and all 🙂
Soros IQ120? Time to move to Tesla IQ151
😅nice
First off, I love your videos, but... please, please cut the "reforming" nonsense and buy a new cap if you really care for the CRT.
Even expensive caps like these cost far less than good CRTs these days.
I'm hoping you used leaded solder when reflowing those joints as you shouldn't mix leaded and unleaded solder.
Could you please deactivate the auto-translation of video titles? Sometimes I don't know what the video is about 😅, and most of the time these titles are at least cringe-worthy...
First 9 minutes is unnecessary rambling
I mute his videos
He suffers from “grade school student trying to meet word count requirements syndrome” and it drives me up the wall.
Video enjoyment goes up exponentially when muted.
@@unfieshow the heck do you watch a muted video? If you say he talks a lot, then you have to read a lot of CC text...
@@unfies true, his 9 minute "intro" could have been easily done in less 30 seconds...
"Let's try to repair this board but if I can't we will use this switching power supply instead, let's get started"
@ the shots of the boards and parts are good enough to know what’s going on and most diagnostic stuff flows in same flow charts. No CC needed. A testament to his high polish video production.
@ very true. And much of his diagnostic work is repeating what has already been stated. A > B (explains why A leads to B) > C (explains A and B again) > D (explains A and B again). I kinda think he’s treating all of his videos as very basic introductions to electronics repair lessons (teaching via repetition in particular).