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- เผยแพร่เมื่อ 7 พ.ค. 2024
- On the bench a dead - and old - ATX power supply I've decided to fix. Is it worth my time?
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00:00 intro
01:52 Overview
04:00 Diagnostic
05:45 Oscilloscope testing
08:05 Actual troubleshooting
06:45 Testing the outcome
18:19 Components replacement
19:47 Testing again
21:30 Fixing the fan
23:53 Load test
25:10 Outro - วิทยาศาสตร์และเทคโนโลยี
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You did no harm to anything and really had nothing to lose by repairing it. Learning in the process is what is valuable to us anyway. Good job Tony. Enjoyed the video.
Thank you!
Cool repair. I like you changed your mind, old PSU are getting rare, and yes, one that can do -5V it always more valuable. Also kudos for listening to a commenter and even crediting them. I wish more YT channels/creators would do that.
ahah thanks! I know what you mean, I've been credited by others as "some people say that" - so annoying :)
I appreciate your kind words, thanks!
Yey, Ton359 video! Thanks for making Friday more bearable! I fully support trying to fix things, that are broken, instead of simply throwing them. Great video, Tony :)
One small suggestion: when cleaning fans and trying to quieten them down, you can remove the white plastic circlip on the shaft, then pull the propeller out, then clean the shaft, the magnet dust and the bearing with WD-40 or IPA, then lightly grease with silicone grease. I have found this to be the cure for loud and vibrating fans with a needle shaft design. Then its simply a matter of putting the white circlip back in the groove on the shaft :)
You know what, I thought about that circlip (thanks for telling me how it's called!) - you see me fiddling with my tweezers at some point. Eventually I didn't try because I thought I might break it. I'll definitely try next time, it sounds like THE solution :)
Thanks for watching!
@@tony359 There is a slit in it, and I tend to collect dead fans, so keep them around as donors if I need to fix one. After all, to get it out you need to have side access, easy if you are breaking the rest of the motor, plus you need to often get extra little washers that set the float at the other end, as those also break or go brittle. Plus you get ball bearing ones, where you destroy the bearing removing it without damaging the shaft, but can destroy another to get the bearing out intact. Just a drop of oil onto the bearing, and leave to wick in, makes them run nice again, though getting it to the bottom needs some pressure applied to force oil through the top one, and down the shaft to the lower one. Needle through a spare rubber cap to provide the oil and pressure works, just press down on the cap to keep it on.
@@SeanBZA Thanks for the extra info!
Awesome fix!! I would have thrown that junk fan out LOL. I actually save these P4 PSUs for their beefy 5v but also the negative rails as you pointed out.
Yes, I definitely spent too much time on that fan, I wouldn't trust it when brand new!! That said, I have a box full of fans but I don't think I have 80mm ones or maybe just a couple. Thanks for watching!
Very nice diagnostic! I hope one day to be able to figure out and debug electronics like you do! And this ATX power supply is definitely worth to have around - just in case you need that -5V rail.
Well, I'm sure your 5 Asus mainboards will give you an opportunity to practice :)
I wouldn't have gave that power supply the time of day until you pointed out the features it has. Ill probably start paying attention to some of the older power supplies i run across.
I need to thank my viewers as it went very close to the recycling bin :)
Thanks for this, I have modified quite a few old PSUs in the past to create variable output bench PSUs, but I have never understood how the low power circuit with the smaller transformer operated, makes total sense now. Glad to see someone actually do a repair by finding the fault instead of firing the capacitor shotgun at it, even if it was capacitor issues in the end. You certainly have earned my subscription.
Thank you and welcome!
Thank you for the awesome repair video! I always see videos where they change a swollen capacitor and they are done BUT that never happens to ME LOL! Seeing your troubleshooting is really inspiring and gives me confidence to keep trying and learning!
ahah thanks! Yes, sometimes I ask myself the same question: why it's only easy to others? This one was a pleasant surprise, though I like learning things and just swapping everything wouldn't have been as rewarding! Thanks for watching!
Very satisfying to watch. The things you've learned during the repair were totally worth it. The next thing I'd have tested would have been the two TL494 outputs that switch the two small transistors that drive the base transformer. Sometimes those die as well. On the mains side of that base drive transformer there are two small electrolytic caps, typically 1uF, which are very important for driving the main switching transistors correctly. If those are dead, the main switching transistors can overheat and self destruct.
Of course, plenty of other things to check. I think it was the PS3 power supply I fixed in another video which had VCC but it was not switching - despite all the "alarms" were not on. So in that case a new (expensive!) controller IC fixed it!
Thanks for watching!
Thank you for this repair! I was hopping to see it, we always have these cheap PS and we all agree that these throubleshooting is awesome!
Thank you!
These ATX power supplies are relatively easy to fix. Most problems are failing electrolytic capacitors and shorted switching transistors. Some times just a crapped out cooling fan. Components, except for a controller IC, are leaded through hole parts. I"ve repaired several of them over the years so I have a few for emergency replacement in my half dozen desktop PC's around here. Considering how cheap they look they are really quite rugged and reliable supplies.
After cleaning and checking wire connections and solder joints on the circuit board you are ready for a smoke test. Use a series tungsten lamp if you don't have a variable auto-transformer and AC current meter to monitor power consumption from the Line.
After power up and no smoke the next thing is to power down and start looking for capacitors with high ESR (Equivalent Series Resistance). Replace any that show significantly higher ESR than a new capacitor shows. Then the next thing is to look for is shorted or open semiconductor junctions. Same again, replace those that can't pass a proper transistor functionality test.
Your chance of having found what was killing your power supply is very good at this point. Good luck!
Indeed - though you'll find a couple of videos on my channel where the fault was different. Those were fun to fix! But yes, let's say 90% it's the caps :) Thanks for watching!
Great job you did Tony. Nice to see that you repair a power supply. Greetings from Steven from the Netherlands
Thank you Steven!
Learned quite a few things, thank you, sir!
Amazing, thanks!
It is amazing, me as you and many others prefer to repair instead of send to trash. I like to find a solution and repair instead of to replace, sometimes electronics, sometimes enclosures, mechanical parts or plastics from box, etc. Thanks to share this interest to maintain!!
No worries and thank you!
I very much like this format. Very useful and yet entertaining.
Thanks for your kind words! :)
Thanking the sponsor is never wasted time.😁
yep :)
Sponsorblock makes sure you dont waste time.
Ah, amazing! That is going to work 100%. Once the sponsor doesn't get views or clicks, they'll stop sponsor the videos and we'll all stop making videos! 100% save of time as you won't have videos to watch anymore! Fantastic, thanks for the tip!
@@tony359 I don't want to hear it for the millionth time - if you don't like it - here's a tiny violin and get a better hobby, cause adblock and sponsorblock aren't going to be turned off, ever.
I never thought I would see someone bother to repair a Q-Tec PSU. They always were noisy and unreliable before. But this was educational and that made it worthwhile. Still wouldn't use that PSU though! Those and Bestec - steer clear!
Indeed, it's for fun! I played with a socket 7 motherboard today, I looked at the Q-TEC and thought "nope" :D
Who would've thought that cheap ATX PSUs would get some TLC! I had a 24V PSU based on the same TL494 and configuration. Everything seemed to check out except the TL494 didn't get high enough voltage just like yours. Even though the high voltage switching transistors measured good, they were bad under load. Replaced them and it was fixed! Always a satisfying feeling :)
interesting and yes, it's a great feeling!
Great video!
Thanks!
One more comment... both of those negative 5v solutions you mentioned practically use a negative linear regulator like 7905 or LM337 to produce - 5v from - 12v - as you can see - 12v is not that well regulated in most power supplies (because it's only used by serial ports where anything above around - 8v is good enough) but it's also available in limited amount, often under 0.75A of current. So those boards make negative 5v but it would be in very limited amount, if it's actually needed (let's say by an audio amplifier that needs +/- 5v on an ISA card) it may not be good enough.
As for the comment at the end... I wouldn't trust it to be capable of 35A on 5v .. the label even says maximum 180w on both 3.3v and 5v combined, and 35A on 5v would be 175w but I'm not sure that transformer is good enough to do it. Also, if you look on the heatsink on the part number of the rectifying (schottky) diodes you may find out it's a pair of diodes that can do maximum 30A or something like that. For 20-25A, it's most likely fine.
Oh, I don't trust that label for a second, this PSU will explode if I tried to pull 35A from it! :D
Re. the -5V, this PSU is rated 0.5A at -5V so I guess the requirements for that line weren't a lot back then? I suppose this is why other solutions work with voltage regulators which don't output much current. I really don't know what cards need -5V though!
Hello there!
The requirements of the -5 appears to be minimum, you might find Doc TB ATX2AT Smart converter page about his measurements on the negative voltages interesting.
Thanks!
@@tony359 Not many these days, as there are really no plug in modem cards around, which used -5V for the audio path, while RS232 still uses the -12V rail. Have a Dell PC where the PSU only supplies 12V, on 3 rails, and the motherboard provides the 5V, 3V3 and core voltages from that, with a small SMPS buck converter doing the standby rail. As it only has PCI and PCIE slots there must be a tiny one only to do -12V from that main 12V bus.
As soon as you zoomed in, I could clearly see some bulged capacitors, which is quite common for devices of that time period.
Yes, I noticed those during the "Retro PC upgrade" video - but it's nice to actually see the problem on the scope! Thanks for watching!
My old backup computer, a 2008 Lenovo ThinkCentre m58p had a boot loop problem that slowly got worse, meaning it occurred more often. That pointed me to the PSU. After replacing the bulging electrolytic capacitors, all was fine again. I also replaced the other remaining electrolytic capacitors. Anyhow, despite the computer being 16 years old, it can still handle 1440p resolution TH-cam videos at 60 frames per second. Repair cost was about $9.95 CAD.
The amount of electronics going to the landfill because of simple faults is sad. But for a non-skilled person it doesn't make sense to have them repaired as the repairman cannot charge $9.95 or they won't get to the end of the month. So we buy new.
This is so very broken. Thanks for watching!
@@tony359 Yes, but I am glad I have had experience in the electronics field. Each of the following broke down at one point, but all are up and working to this day. My 1976 home made speakers. They required replacement of the outer foam rings of the two 15" woofers. My 1976 Heathkit AA-1506 120 watt audio amplifier. My 1976 Soundcraftsmen PE-2217 Equalizer/PreAmp. My 1999 Schwinn 6700p treadmill. My 2000 Danby Simplicity window mount air conditioner. My 2001 Palm m505 PDA, which I still use just about every day. My 2004 stainless steel microwave oven. My 2009 Black & Decker coffee maker. My 2010 Samsung TV. My 2014 Samsung S23B300 computer monitor brick power supply. Plus a few other odds and ends have been repaired. The most costly repair was for the 2 foam rings for the woofers. Sadly my 1987 DENON DCD-900 CD player, which I have repaired before with easy fixes and still looks brand new, recently had developed an IC problem. I might repair it. Not sure yet. Perhaps you can tell that I like repairing things. LOL
Friends often wonder why I have "old" things at home! :)
@@tony359 Is it just me and what I see, or did my last comment vanish ?? Update. On one of my computers it does not show up if I am logged in and am using Firefox., but does show up if I instead use the Edge browser and am NOT logged in. So I checked this again on my Lenovo backup computer. Here it does not matter which browser I use, nor whether I am logged in or not, it still does not show up. Weird stuff.
I can see it. It's not the first time my comments "disappear", I guess it'll come back at some point. It wasn't me though :)
Fantastic work, thank you.
Requests: Test the replacement caps also so we can see the difference (ESR). Show the output on the scope before/after (you did do some of this).
Well, I felt something was going to explode if I had kept the PSU on with those bad caps - but yes, I didn't test a new cap, apologies! I'll keep that in mind for next time, thanks for your comment!
@@tony359 Thank you Tony, keep at it!
You know what Tony, you're one of my favourite creators on YT. Your editing style and general attitude is great. Keep the videos coming! Also, if you feel you're going to do more power supply repairs I can't recommend a Peak Atlas ESR 70 meter enough. It's great for checking capacitors in circuit!
I definitely need a better ESR meter for sure :) Thanks for recommending and also for the kind words :) Editing these videos is quite time consuming so I particularly appreciate the comment! :)
Very nice work. This is my first time on your channel, so I'll check in on some other videos and maybe subscribe. I have several power supplies in a bin on my workbench, and all but one of them work. The dead one is an old 20-pin ATX kind of like this one - a very heavy +5 volt rail, and might be worth the effort to repair it.
Thanks and welcome! There are a couple more power supply repairs on the channel, one is a PS3 one and another one a generic one. I hope you like them!
Great video as always Ton359 👍
Thank you!
I would recommend replacing those two large mains caps as well.
I repaired a very similar PSU a while back and re-capped the whole thing except the large ones. But it started misbehaving again after a few months. The large caps had failed and 50Hz mains ripple was coming through on the output. The caps had leaked badly, but I didn't see it because the glue around the base was stopping it spreading. 😅
Now this no-name 'cheap' old PSU is one of the best I have. Totally noise-free output, better than another much newer one I have!
Of course, I need to source some! Thanks for watching!
@@tony359just don't waste money going with branded ones, "chong" or anything similar is good enough for these PSUs, it's not like they come even from factory with something better (and managed to work for years used everyday), modern ones even come without plague installed :)
I tend to buy Panasonic - but I see what you mean. Those two caps in Panasonic brand would probably be a lot of money! :)
I should really have two drawers: the good ones and the CHONG ones for such projects! :)
Just as I said it would be the capacitors from the small transformer that stopped it starting.
The fan if I can't get or have a suitable replacement, you can take off the plastic washer on the shaft and take the shaft out to fully clean it.
Thanks, someone else has mentioned that, I will definitely do that next time! Thanks for watching!
good repair.👏👏 I have a few power supplies lying around, they are useful for things like an electric screwdriver, 12 volt vacuum cleaner, etc. I also have a box with dead power supplies that I couldn't repair. I don't have much confidence in connecting the oscilloscope to those things.
Absolutely, be extra careful. I said I am "safe" with the differential probe but you're never "safe" with 340V nearby... Thanks for watching!
Done a few of those, and generally replace the lot with around 1200uF 16V or 1500uF 16V units, as I can get skinny Nichicon ones, which will fit into the space on the board. Close enough capacitance wise, and usable on all the voltage rails. The standby supply I tend to go up in capacitance, and use 63V capacitors there, normally have a good number of 47uF 63V ones around, as those are a common enough value, and I use them on gate motor power supplies, where that, along with some 470uF 35V ones, are generally a quick fix on them. On a PC power supply higher value on small ones works, and on the larger ones whatever will fit so long as it is within 50% of the value also works, they are not too critical, just need a decent ripple current rating and higher voltage, and they will be better than the original MysterLee HooFlungDung capacitors that were used, because those were cheap that day, and fitted the board mostly.
Fuyihuu caps are the best!
That monitor was NOT cheap! I think it sold for £1000 back then. It was one of the best "pro-sumer" monitor you could get!
Thanks for watching!
@@tony359 I saw some capacitors that were marked as Sanma, a cnockoff of Samwha, and some that were NItichon, a almost perfect copy of the Nichicon logo, but the caps themselves had failed while unused.
ahahah amazing!
You saved a PSU with a obscure voltage option, so all good and totally worth doing. Lots of people are about let's save the C64 or Amiga, but there's some cool generic 90s to early 2000s hardware which is worth saving.
Thank you!
Really enjoyed the video, thx for doing it. Video is well produced with care. Good idea to look for a schematic that uses the same controller - for advice. Clever. Loved the drawn traces and wonder what you used to draw them. Also liked that you also make a mistake here and there, and left them In the video - very helpful for learning, going to happen, and "humble is good". Cheers! (Bring Them Back To Life!)
Oh, and measuring the fan's current draw is going to be added to my repairs procedure.
Thanks for your kind words, I'm glad you liked the video! I use Resolve and used Fusion to draw the lines. The lines are also tracked to the PCB which moves slightly when I touch it. It's... simple once you know how to do that :)
Cheers!
@@tony359 TY!
❤
No, it was not worth to repair this PS. At least in the view of price of the PS in the past.
But it was worth for your channel - i know have enough seen how to safe my old power supplies.
Great Job, Well done!
Be careful! And I hope you can succeed! Thanks for watching!
I always give my PC fans a bath of WD40. I fill a small container just big and deep enough to allow the WD40 to immerse them then let them run for an hour. They self clean and to remove excess oil just drain the container and let them run dry for another hour then wipe any remaining excess with kitchen towel and they are spotless and good to go again. Never suffered any harm or ill effect from this so far :)
Sometimes I've washed them in hot soapy water then let them air dry then use WD40 to drive out any water from the circuit board then a drop of 3 in 1 oil on the rotating shaft. That works just as well :)
I never considered bathing a fan in WD40 :)
I tend not to wash anything which has coils in them - transformers, motor coils, as I'm not sure I'd be able to fully dry them out. That said, a fan is low voltage so it should be good! Thanks for watching!
0:29 since you are regularly sponsored by PCBWay, perhaps they could make some Voltage Blasters by Phil's Computer Lab and Necroware for -5V.
When I need one, for sure. Thanks for watching!
22:40 that white plastic is removable (it has a gap that you can spread) that will allow you to separate fan blades with shaft from stator so you can clean it much better. It's pretty easy to take apart and put back together
Thank you - several viewers have mentioned that. I didn’t know that! I was tempted to try to remove that white bit but I was concerned I could damage everything. I’ll definitely try next time!
Excellent
Thank you! Cheers!
I like you red tracing of tracks, thank you! :)
ahh thanks! Now I know how to do it it's not too bad. But it took some time, thanks for the comment!
Nice repair! You can put a thermistor on the 12v power of the fan to slow it down when the PSU is cold significally.
I cannot understand why they stopped putting that female bypass ieee 3pin power socket at the back of the PSUs, it was extremely practical for monitors. Old PSUs are worth repairing, strong 5V, -5V and native AT connectors are 3 good reasons.
Ciao from Grecia, Jim
This doesn't have AT connectors unfortunately, it would have been perfect otherwise!
Thanks for watching!
For a switching supply, you should be using dedicated low-ESR capacitors.
On this PSU I admit I dug into my stash looking for "cheap" capacitors but those are from some time ago. 99% of my caps are Panasonic, if possible "FR" series which are very low ESR and high ripple I think. They're not cheap but I don't see the point in recapping with cheap stuff. If FR are not available I always select something with low ESR as standard.
For PSU - when I have them - I also use the Nichicon PW series which are designed for PSUs.
Thanks for watching.
The squeeling is (probably) normal and a good sign, as it indicates something is switching. The ramp down on the squeel is the voltage of the switched signal suddenly dipping.
Absolutely but it is not audible with the caps replaced - I suppose many caps were leaking and the switching frequency was just making them "sing"? Thanks for watching!
@@tony359 That's possible! It's also possible that the bad caps were causing the switching to be below desirable frequency or something similar. In any case, the noise does indicate a switching IC or something switching works, so it's not completely dead!
Great repair and fault tracing.
Thank you!
true, Tony, luckily i found brand new PSUs which has 38A on 5V and bought 2 of them for my lovely skt 462 PCs. hope BuB will make an announcement about the -5v project, i wanna buy one from him :) cheers, Tony, awesome video
Thank you! BuB made a video about that some time ago and the link to the store is in the description if you want one!
I wonder whether out power supplies can actually deliver 35 and 38 Amps, I seriously doubt it :D
Thanks for watching!
@@tony359 yeap, me too :)
Well, thanks for such interesting and dangerous content
you're welcome! 😊
Inspires me to take a look at stuff in the back of my storage.
Wishing you lots of treasures :)
Good video
Thanks for the visit!
Oh i got your channel recommemded because of this video. Subbed immeditately! Btw can i know whats that device that you use to check the capacitor esr and capacitance ? It looks extremly useful
Thanks and welcome!
It's a basic component tester, there are many different types available. I think the original name is LCR something :) It works very well and it's very cheap. Thanks for watching!
@tony359 thank you for making the video too ! I was doubting whether to buy an oscilloscope for electronic repair since most people on forums kind of discourage it saying its not very useful but after seeing your video I realised its extremely useful rather than just relying on the multimeter. Thanks for the great videos 👍
There are cheap scopes nowadays which work pretty well. But BEWARE, do NOT use a scope on a power supply unless you have a differential probe - a battery-powered scope should also be ok but I cannot be 100% sure. What I am saying is that remember the ground lead of a scope is.... ground. It's not like a multimeter where you can poke everywhere. If you ground something which has potential, you make a big bang :) (Ask me how I know? :D)
At around 3:40, I may be wrong but it is my understanding is that the controller chip communicates via the optocoupler and not the central transformer you mention in your comment. Those transformers should be for 5V, 3.3V and 12V respectively. Thanks for the video!
You know, I am not sure now. Because the controller is on the secondary, there shouldn't be a need for optocupler as the feedback doesn't have to cross the secondary/primary boundary. Interesting.
However, I one of those yellow things (I call them transformers but I'm told they're actually two inductors coupled together - let's call them high frequency transformers) is definitely for the 5VSB and the VCC for the controller, before the main circuit kicks in. If you look at schematics there is usually only one transformer for everything - there will be different windings and each will deliver a different voltage.
I'll check with my "go-to" person when it comes to transformers about the optocoupler, thanks for asking!
(*) - on a more modern transformer, where the controller is on the PRIMARY, then the optocupler is 100% for receiving feedback from one or more voltages so that the controller can compensate for different loads!
@@tony359 thanks for your kind and prompt response! So… it got me thinking, again not an expert here but AFAIK the chopper transformers are those three and no matter what side you have the IC controller you will have to get info across from the cold side to the hot side to provide feedback to control the mosfets transistors across the optocoupler and using PWM to increase or reduce the power as needed. Alternatively if you had the IC on the hot side, then you would use the optocoupler to get voltage information from the other side to feed the IC and again adjust the PWM cycle as needed. Let me know what your “go-to” person tells you because it would be interesting to have a professional’s opinion. Thanks!
@@Snowsea-gs4wu My thought is that the voltage feedback can reach the controller directly, no need for optocoupler. All it needs to go to the HOT side is the switching signal. I'll find out more and report back! :)
I was genuinely surprised, how often are the smaller capacitors bad. They do not even look that bad like the bigger ones which bulge. When I was repairing my old LCD monitor PSU, all of the little ones had big ESR, which is not good for the switching nature of all the DC-DC step-downs or SMPS in general.
Indeed - I think it's because of the broken fan. This thing must have badly overheated for quite some time. Caps don't like heat at all. Every extra 10C the life of a cap halves. So running a cap at 60C rather than 40C means that the life of the cap is 4x shorter, impressive!
I think a sneaky fault is a bad linebus - like the -5vc or something in that order..
I bought a nice old board from 1993 and it came in mint condition - and yes, it still is.
i currently have in on a piece of wood. DeCase-As-it-Is
Yesterday i powered the board - and it did POST but.. didn't find the HD
it's a Quantum Fireball 24Gb and it's recognized by the OS
the controller has a max of 8G ..
Eventually after moving the controller over the board
trying to find a better slot i wondered if there was a PSU signal issue
and behold.. i found a replacement PSU and it booted..
Sometimes all it takes it a good ol' recapping!
Particularly when those prestigious brands are used! :D
You can make a -5v output using a jellybean component like MC34063 or any 34063 / 33063 (first two letters are manufacturer digits, they're made by lots of companies). There's even online "calculators" that will tell you what components to use, instead of you calculating using the formulas in the datasheet.
Typing as I watch at 5 minutes ... esr of 5v standby capacity could be bad, you may be measuring 5v with multimeter but doesn't mean it's ok... the meter puts no load on the circuit so it could show 5v but be actually bad.
Oh yes, the multimeter is doing a broad average - and as you could see later on in the video 5VSB was also all over the place! I didn't check it afterwards though! Thanks for watching!
You have -12V line anyway so you can use a cheap linear regulator.
One of classic ways to get -5V from +5V is a standard 7660 IC which is much easier than 063 since you don't need an inductor, and you don't need even any resistors, simplest IC to use. This IC comes from half a dozen different manufacturers. It's not intended for high current but it'll hold up a negative rail of an opamp perfectly fine!
Hi Tony, just started to watch this video, in my experience it mostly turns out to be a capacitor, usually on the outputs or the start up supply, sometimes an output diode, they look like transistors or Mossfets, but they are power diodes. Bob. I will be interested to see what you find
OH! also sometimes the startup resistor goes very high in value.
Edit: Well done Tony, for information it is rare that the big mains input capacitors have to be replaced. Bob
You were right indeed - I hope you enjoyed the troubleshooting process! I'll consider the input caps, they can be expensive... :) Thanks for watching!
It's not only about the heavy +5V rail, it's also the -5V, that doesn't exist at all on newer PSUs. ;)
Absolutely! Thanks for watching!
I've repaired many SMPS's and in the majority, the problem is always the electrolytics. Some are obvious, bulging out the top. Otherwise, check for value and ESR.
Particularly those cheap ones had cheap capacitors - and cheap design which meant the capacitors were stressed more than needed. Thanks for watching!
Good repair job, yeah caps all the time
Actually you were lucky, when the caps get this bad, all the transients from the switching goes through the roof and can easily take out an active device, often the switching transistors, meaning a near dead short across the input, smoke and severely cooked parts.
I was surprised the monitor was still working! I didn't think of checking those caps... Thanks for watching!
Edit: wrong video :D
Yes, those were not caps anymore :)
Much of the noise you see on your scope comes from improper probing. You need to limit the ground loop on your probe, for example by using a proper scope probe with the ground spring clip. As it is you have massive ground inductance which HF decouples the scope ground causing lots of noise on the scope that isn't really there...
Thanks, I am aware of that. I am using a crocodile clip on the scope ground probe for convenience. I am fully aware this will introduce noise but it shouldn't be more than some narrow spikes which are not relevant to troubleshoot a non-working power supply.
Years ago I was fixing another power supply. I fixed the main fault but then I could see narrow spikes and the device was medical grade so I was not expecting them. I had an identical one (fully assembled in its cage) which didn't show the issue so I kept working on and off on that board for ages.
Only after LOTS of time I realise the noise was coming from the power supply itself because to test it I had to take it out of its cage! :D :D :D Once back into the cage, the outputs were perfectly clean! :D
Thanks for watching and for your comment!
i have so many smps's lying around most of the don't have 5v Vsb o/p, going to buy a lcr meter soon for changing my game, most of smps faults are due to bad capacitors, i once had a working smps wanted to use it as a power supply for my tire inflator it requires 8A @ 12v, i only wanted the 12v line, also kept a sata & a molex connector just in case required for cd rom /hdd, so i desoldered all wires & connected only a 12V line ps-on 5v Vsb, after that tried to turn on the ps on it would work only for 2 sec & then off, did trouble shooting checked the o/p section nothing was bad, turned out the 3.3V sense wire should be always connected to the 3.3v line, everything works great till today.
well done in discovering the 3.3 sense line issue!
@1:55 I can see 2 bad caps from here, tops are bulging very slightly.
Yes I think 2 or 3 caps were obviously bulging - but I think only 3-4 tested "ok" when I swapped them!
You did not check the large rectified mains capacitors. I have found that these capacitors go down in value the longer the power supply is powered up. If these capacitors are more than around 30% low in value then it affects the maximum power that the power supply can deliver.
I did not indeed. The main reason is that... those are expensive and I didn't want to invest that money on this PSU! But you are totally right, if I ever put this PSU in service, those should be checked/replaced too. Thanks for watching!
I just used WD-40 a couple hours ago to clean a part.
Yes, WD40 is a good cleaner - but I don't recommend using it as a long term lubricant. Thanks for watching!
After couple of years my subwoofer slowly start to make strange noises. During investigation I found similar glue that starts conducting after time. Removing it reduced noises considerably. Other culprit was potentiometer.
I'd imagine that where sound (low levels) is involved, that glue might add havoc! Thanks for sharing!
Nice video as always :) One note: there is no reason to believe the sticker on this PS. In early 2000s the orders going to chinese factory always had two field: power and power on the label. True story.
ahaha - I have no issues believing you. And it still happens in many fields unfortunately. I'll pull 35A from that thing next new year's eve so I can save on fireworks.
3-2-1 (BANG) yeeeeeeee :)
Halleluja! Another PSU saved!
:)
HELP! Assistance please!! I have three Cooler Master power supplies, all at or over 10 years old. A 550, 620 and 650 watt. All three still work but under load cause burps and reboots. I'm told they all need new capacitors. Is this feasible and reasonably cost effective? Can you gives me some hints and suggestions? I counted around 50 capacitors in the 650 watt one.
Hey hey. Tony working with capacitors and just an hour ago I got my cap kit for my xenon mobo xbox 360. I successfully RGH 3 a trinity a few days ago. Just picked up 3 more xbox 360's for $30 USD. My workbench is xbox modding central now lol.
Capacitors everywhere! Don't miss the next video - more capacitors but... with a twist :)
@@tony359 ooo sounds good. Thank you Tony!
What lubricant are you using for that fan?
it's called 3 in 1 here in the UK. A generic lubricant.
I do have two micro atx power supply which makes squalling noise too. Can you please tell me what is the problem? Thanks
it's impossible to say from here I'm afraid.
Nice graphics showing traces!
Hey thank you! I'm sure they're easy to do if you know how to use Fusion - but I'm not that person so it took me a while :)
I told you it'll be easy :)
ahah - it's always easy when you know what to do (which I don't BTW!)
Q-Tec are bottom of the barrel, they die if you look at them while wearing shades. The only way to fix them is to gut it and put a pico in it. :P
I had the misfortune doing support for a shop that sold them for a short while and I don't think a single unit survived longer than a year. Ok I'm exaggerating but the failure rate was astronomical. They were included with a lot of cheap cases back then, good thing they were dropped by most of them AFAIK.
TLDR, I would never use it on any system, as soon as you put load on it it'll fall apart.
ahah I believe you! After all they came with two VERY cheap cases! :)
@@tony359 still a fun video though, you did a good job getting it working. Well... "working" as new lol.
1:03 I am worried about any power supply that calls the colour of its wires 'Purply'
Ahahahah I totally missed that!!! Amazing!
. . . I have had properly lubricated fans last 35 years and counting . . .🎉
Nowadays we know Qtec under the name Trust Peripherals ;)
Ah, interesting. Trust was low end but not so bad?
@@tony359 Hmm, yes, Trust used to be better than it is today, cheap and of high quality. I still have speaker boxes from 2000 from Trust with 240w, you can actually compare them with my buddy's Bose sound boxes in terms of sound... 7.1 surround and 300w. However, these are made entirely of cheap plastic. The Trust have a solid metal grille at the front. Bose = $250, Trust = $20 ;D
Qtec became Trust in 2002.
Where did you get that dummy load?
I've just added a link in the description. I love it - there are some bad comments online, it's cheaply made but it's really versatile. I "tweaked" it a bit - new thermal paste and a heatsink on the main diode.
@@tony359 Thanks! 🙂
No oscilloscope after cap replacement :(
Well, we did check the VCC line after the cap was replaced. Everything else was not checked because the PSU was making a squealing noise and I didn't feel comfortable running it in that state. Also, the length of the video comes into play at some point and I have to choose what to include and what not. But thanks for your feedback, I'll definitely keep it mind and thanks for watching!
@@tony359 at least I know now what means a good and bad power supply. I expect from a good one to be without such noise and also I see that caps may look very ll from the outside and be crap on the inside.
Блок мечта ремонтника. Жаль ремонтировать такое коммерчески не выгодно. А так схемотехника источника питания простая как чайник, а выходят из строя конденсаторы. Лучше бы автор не юзал дифференциальный пробник для ослика, подал вольт 30 переменки на вход и безопасно тыкался. И сигналы от шимки и дежурки и на силовых ключах. А так тыкаться под 300в неизолированного сомнительное удовольствие.
Google translate is a bit unclear, I understand I could run the PSU using 30V AC? I wasn't aware of that, though I don't have a way to generate 30V AC right now. It's definitely not nice to work on something with 340V DC on it but at the same time it removes any unknown from the equation.
Wait, I just remembered I do have a big variac :)
i have PSU when i play games on full load its shutdown , is there chance to fix it ?
Anything is fixable but I'd advise against trying to fix an item which has 340V inside without knowing exactly what you're doing. The very Cooler Master you see in the video was replaced because it was shutting down randomly. I've used in my workshop for years and it never failed on me.
Intermittent issues are the worst to diagnose.
But first: are you sure the power supply is capable of delivering power to your system? What are the specs and what is the power supply?
@@tony359 im not gonna fix it 😁😁 all i can do for now is soldering , maybe PC repair shop but i will tell u the brand it Chinese 600w from 1STPLAYER black widow , that is PSU name . its too silent i have another one from ViewSonic high quality and heavy but not silent like the Chinese one
A quick search online seems to suggest the "1stplayer" brand is not great (I am being kind) so maybe you should look into a good replacement!
@@tony359 i do have ViewSonic 700w but on full load like a vacuum its too noisy "fan" about 1stplayer their cases is great i give them that , my last question is what is difference between gold and bronze psu , is that matter
It's the efficiency, if you google it, you should find plenty of info.
If the 1stplayer is as bad as I read, I wouldn't want it in my computer. It's been called the "computer killer" for a reason...
Yeah, you couldn't pay me enough to fix those krusty atx psus, collect, drop off at recycling, get some scartch.
A new one will grt to me faster than I'll start all the machinery and diagnose and order parts etc.
Saving time and money has never been the purpose of this repair nor the purpose of this channel!
@@tony359 hm, the answer was in the thumbnail - everytime anything end in a question mark - answer is a resounding no.
Law of headlines.
q-tec was the lowest of the lowest quality back in those days. My dad had a "400w" q-tec, it had 3x 80mm fans and melted thin wires in his pc.
Wait a second, are you telling me that FUHIYYU is not a good brand? I am shocked. :D
The worst of the worst, why am I not surprised! LOL! Thanks for watching!
The PSU has extruded heatsinks. So it's far from the worst I've ever seen.
You're right, I've seen those with small metal plates in place of heatsinks! :)
@@tony359 the real junk has aluminum sheet metal with some slices for fins and bent back and forth. When you opened it up and I saw the extruded heatsinks I thought, not half bad. I wasn't keen on the lead length they left though. It looks like they didn't clip the board after it was wave soldered. They just trimmed the parts short before they stuffed the board.
I don't know why I always see the same mistake with lubrication in your videos.
You lubricated the plastic ring that retains the fan shaft. Not the fan shaft.
You need to take that white ring off, take it apart, clean and lubricate the shaft, and put it back together.
I see similar things like when you want to lubricate stepper motors, where you never lubricate the bearings but instead apply oil to the shaft. Which doesn't help.
Good reparation video.
Well the answer is very easy... I didn't know that! :) Others have pointed that out so I'll definitely do that next time, thank you! To be fair, I thought I could remove that washer - you see me poking with a pair of tweezers - but my concerns was that it might break and then no more fan. I don't have many 80mm fans so I decided not to push my luck. But on next occasions, for sure! Thanks for mentioning that!
That said, I can assure the oil I apply drips down the shaft, it doesn't just stop on the washer. Same with the stepper motor - I guess you refer to the IBM drive - the oil definitely went into the bearings.
Thank you!
OMG this power supply is as hideous as its outside suggests! Starting with lack of E-number that would point to a known manufacturer... the complete input filtering has been unstuffed and bypassed, PFC is removed as well, the only concessions to compliance you get is inrush limiting (without bypass relay) and a fuse.
I do have some of that era's PSUs for when i might need them but they're all FSP and the like, reputable.
Haha typical capacitor squeal! They're begging to be put out of their misery!
I notice you're not paying attention to the most important measurement of the LCR T4 - VLoss. It's REALLY bad on all the capacitors that you show measured with even the 330u one being if not quite as completely dead then about borderline. What it means on these LCR T4, is how much voltage has dropped when you leave the capacitor alone disconnected for one second, and normally you expect a capacitor to hold for minutes, so anything above a couple percent is a failed capacitor. High VLoss also means the capacitance reading is completely unreliable, it reads much higher than the real capacity, because from LCR's perspective, the capacitance is how much power it had to put in to reach a certain voltage, but the energy kept getting burned off and turned into heat as it was getting put in, as seen from VLoss.
I almost don't beileve in bad caps. I mean yeah they are low grade here but you're also not seeing any attempt on this PSU to limit the amount of ripple current they have to handle, no parallel ceramic capacitors anywhere. Often i see capacitors fail due to bad placement simply too close to some other heat source. You can get a lot of mileage out of cheap caps and good engineering.
On PSUs of all things i prefer not to live probe and trace faults for safety reasons, because there's a small chance for things to go wrong and i only have so many lives, and the amount of time and effort to ensure and double check i'm doing everything as safely as possible is just too much. I just discharge everything, do some in-place measurements to confirm as many parts as possible don't have obvious faults, take out all capacitors except those of which i pretty much know they didn't fail or don't matter, test them, and then rebuild the PSU. I don't care about elegance when my life is on the line. And i mean what, it's not like i'm wasting components by replacing ones which are obviously bad, need to replace them anyway!
Thanks for the explanation, I planned of checking what that VLOSS meant, now it's clear! The power supply is connected to an isolation transformer with current limiting - I know it doesn't give me 100% safety but maybe a little.
And I see what you mean with "good design will extend capacitors life", it's a very interesting point! Thanks for watching!
Please do not wave metal leads along pcb. One wrong move and you got yourself an explosion. I know the hard way😢
Can you point me to the moment when I did that in the video? Not arguing, just curious!
It's always dangerous to work with an open PSU. But I always use my isolation transformer which also features current limiting. It was set to 60-70W. If I shorted something, I get a "piff" - though those large capacitors would definitely make quite a spark :) But the PSU is not directly connected to mains. I do appreciate your feedback though!
Good to know. One cheap way is test-powering psu through a 40w incandescent bulb for current limiting. I am not saying you violated hot part of pcb anywhere, so i can't say, sorry. it just feels so dangerous. When my single big caboom happened to me i wasn't in any way ready for it. And then my hands are charred and i am in shock instantly.
The Bang Preventer I am using is exactly that :) th-cam.com/video/38jQtb0LAhA/w-d-xo.html
Working on power supplies IS dangerous. But the limiter should avoid the worst. And the isolation transformer should help too. Sorry to hear about your experience.
Is it just me or this Fuhjyyu is "F*ck You" in Chinese or something.
😄😄😄😄😄😄😄
I miss the vintage moather boards repaiers, this what drive to start waching you're channel. but ive see latley you stick on comodore and other not interested computers. i fell a bit dassapointed with you're last videos. I'm also sick of pcb way and was extreamlly dissapointed wen ive stared to seen in on the channel. if this is hoby for real then making money shoukd not be a priority, thefore we should not see sponsored videos, but sadly this days its all about the money.......
Hi - thanks for your comment. I haven't posted a Commodore video in a very long time, are you sure you're not thinking of another channel? Regarding repairs, I do what I come across with. It cannot be motherboards all the time! :) Anyways, I hope you keep following and find something that can entertain you! Thanks again!
I have seen caps age and go down, but SO MANY, WOW!!!!!!!!!!!!!!!!!
ahah yes, this was a cap cemetery :)
Careful what you use the power supply for.
I had a PSU that went down and went high over voltage as it died and TOOK OUT my MOBO and four large and expensive hard drives
Yes, that's why I tend to use high quality PSUs in my computers. This one is notoriously bad quality so... well, it was an exercise, I learnt something from it :)
gate drive "separated for safety" Huuuggghhh???? I don't think so! It is BECAUSE they are referenced at different voltages that would OBLITERATE the gates of the mosfets!
Of course but I think what I meant was that primary and secondary are also separated for safety, no? Components might fail and you don't want 240V or 340V DC going into your PC. In this case obviously the separation also achieves what you say. Feel free to correct me :)