The blue component wrapped in heatshrink you removed is most likely a MOV, not a cap. Metal Oxide Varistor. It goes short-circuit when the voltage across its terminals exceeds a certain threshold and blows the fuse for overvoltage protection. This supply most likely experienced a surge on the mains.

I have spent 3 decades repairing electronic boards. I really enjoy watching you because these repairs are difficult. I like your camera set up and electronic equipment. I’m an old dog looking for new tricks in the electronic field. I would use an infrared gun to see what’s so hot. Harbor freights for 20$ infrared Gun. Soldering iron not hot enough? Then heat soldier on pin and add fresh soldier to that pin. The new soldier will heat the pin up faster and penetrate the board. This is my 50 th year in the Petrochemical field. I’m an Instrumentation and license journeyman

You with power supply, myself with my home '08 LG 42lcd with bad gamma chip AS15-F on the tcon. Currently pondering on 1) change for 3-4€ the broken smd /may get it tomorrow but have no advanced tools at home, 2) change the tcon board for 20-30€ 3) for 2x the tcon price, get another same model lcd. Ah fixing modern electronics!

dont be daft your not old pal. keep up the good work

Better to use a series bulb for testing if u r afraid of fireworks ☺

Varistors are used to protect a circuit from high voltage surges, in other words MOV or TVR, really need to replace that capacitors that has swollen, Power supply will be unstable

Thank you so much for doing this video. I am watching this over and over again cause I have a similar problem. You have no idea how much it means to me to have a step by step I can follow. I am so happy you read my comment 😊

The independent power supply is a fantastic diagnostic tool; essential for fault finding ! Absolutely fascinating Sir !

That fuse is approved and calibrated to UL specifications.

Haha, thanks for granting my wish ! I just used today a old desktop PSU for power up a car amplifier to use in my garage, and it works nicely. Great video, and That Manuel reaction cracked me up.. lol ..

People say you are dodgy. They should see someone cut the wires from a mini psu, solder them to a normal psu and use it outside the computar box as an external psu. I can confirm it does work. Looks like crap, but works.

I just love these videos! Capacitor shorted usually explode.

Power supplies of TVs and computers are my daily tasks, not so hard to repair, they are the most common fails, and a good money to earn by quantity, it require some experience. But i really find it easier than your usual jobs :-D. The key element in power supply it to always firstly check the switching transistor or IC and diodes to don't lose time, it is the main culprit when any shorts occurs.

Well done sorin :-D It's possible the 12v supply has a dodgy capacitor, less voltage than expected.

Hy Sorin, always is something to learn from your videos, carry on, classic nice one with the smoke recognize , you need to make some video about smokes faults type

Helpful repair video

thanks for sharing. you are helping me a lot.

21:26 ist not a capacitor its a voltage dependent resistor

We need more desktop motherboard and psu repairs master...

High end PSU's are a good source for high end transistors, buck convertors etc. Usually half bridge topology but i can get hard to tell these days with layout. Its worth fixing certain PSU's i know a fellow who does the stuff rated for medical devices... good money.

Thanks for sharing. It’s good!

Nice video

Sorin, which flavour do you like in your vapor the most? burnt capacitor or semiconductor? but really, when doing this kind of work on power supplys, i recommend you to get an testing-transformer, that can be regulated from 0-250V AC and has a short circuit limiting to 3-5 Amps, so you don't get the entire short-circuit-current with arcing from the public power line. Every Radio and TV technician used these back in the day. Another advantage is, that they're not grounded, so you are 1 touch farer away getting electrified.

Thank you very much.

when i did hoe and small business PC and Networking 20 years ago we had a client that had an expensive CNC machine that ran off a windows 98 pc. he said he could take the hard drive out and put it into another PC but it had to be the same make and model mainboard , network card, modem and especially video card or the program for the CNC machine would not load. We had a scare when he called our dispatch department and said his computer would not boot after a thunderstorm. I went there luckily it was his power supply. He said it would cost $159k to upgrade to a whole new CNC machine and a new windows xp PC. I told him i would go on eBay and try to find like type hardware listed hardware for above for the windows 98 pc. Never saw him again, got a corporate IT job.

BOOOO!!! You forget about that swollen capacitor here 4:01 The output voltage will be unstable during load, and on one day it will fails again. And as lot of people have said here, that blue element was MOV/varistor not capacitor. BUT I did the same mistake as you. Becasue it has blue color, I think the same as you, that it was capacitor. I justed to see mov/varistor on yellow or green, or red/brown color and blue more often used for capactiors. So this one i understand. But not that swollen capacitor form the beginng. it is fail :)

Dear sorin you are grate , like these devices i use series lamp tester with 200 watt for test power supplies i made it in a box with 2 lamps on series it is more safe for test not to blowing the parts and put it with your other testers also I figured that you dont have solder sucker tool its important with boards like that its useful for you .. regards

Your tips are always good but what do you do when repairing a motherboard and there no form of heat on a dead motherboard but it is getting voltage

How the hell do you keep from losing screws. If that was me they would be all over the floor and disappeared.

Nice screwdriver!

Greetings! Great channel, watched every episode. I bought not knowingly ps4 with BLOD... Will there be episode about it, what is easiest way to pinpoint a exact reason of malfunction. Analog multimeter and simple soldering iron are all tools I have.

thx for this

I know I am late to the party, but I have seen things like this while working on my JVC Home theatre setup that kept blowing the main filter capacitor. What happens is that this has a complicated design that makes the first filter caps act as a voltage doubler. There is a voltage sensor circuit in the input calibrated to 120 volts or so. If the input voltage is below that, the system senses it as connected to a 110 V supply (US) and connects two nodes via a triac to act as a voltage doubler. If input is more than 120 V it senses the input to be from 220 V and disconnects the doubler network. While this setup worked ,the main filter cap always see 220 V and is rated to max 400V. In my case, the triac shorted to death leaving the voltage doubler to be always on. When plugged in to 220V supply that filter cap got fed with 440 V and fried. Removing that shorted triac solved the problem.

Put. Normall 100w light bulb in place of the fuse if it glows bright it’s still short if it’s dim or pulsing it’s ok and fixed

Im in a phase where first thing i do after i see Sorin video is like.

Thank You .

love your videos =)

Heh quite a smoke test. Nice vid by the way!

16:11 you can feel the smoke .... best part

Also if try continuity on the mosfets output and input its shows no resistance like its shorted, or somevhere else, could I check that with analog multimeter?

you need some low melt solder to help your iron get of high temp bits off the board

Amazing video Mr. Sorin! As always, of course. Where did you get that cool electrical screwdriver? If you don't mind me asking.

Get a solder sucker Sorin and replace the over-voltage protection...

Hi I would like to know which type of wire You used as a temporary fuse until You put a actual fuse in.? I have a Power supply that fuse blew but can not find out why the fuse blown yet even after replacing Fuse.

Brilliant !!!!

Hi sorin don't you have to replace the burned capacitor?

Whilst I get that the knowledge share of diagnosis is very good here, it worries me that for the sake of a couple of components (fuse, MOV etc) you are showing that a bit of wire or leaving out bits is acceptable, even jokingly (for testing I get it) - even if the fuse or MOV was replaced off camera, I'm sure there are viewers out there that think a bit of wire or omission is acceptable because that's what they saw and will then go away and do the same without realising. All those bits are easily available from CPC, Farnell, RS etc, even Ebay for one off and hardly a long lead time (or even pillaged from another item). I get that for low voltage stuff, leaving out the odd component (e.g. smoothing cap) is probably going to have a negligible effect, but on the mains side it's not worth the risk in my opinion (even if there are other safety measures in place e.g. plug fuse, MCB etc) - the day one repair has a consequential loss and the repair industry gets a bad rep and gives the anti-repair lobby something to use as a stick is not worth it for a few pence on a fuse or MOV in my opinion. I like the fact that you are prepared to share knowledge but it would be good if you can conclude with the next steps i.e. fuse and MOV *should/will* be replaced for best practice :)

Let the magic smoke appear ! 😇

It is just a capacitor to filter high frequency noise signals

‘X’ and ‘Y’ capacitors, as well as TVR (or MOV) and fuses are important for security and should always be replaced.

Sorin: You have over 130k subscribers. Someone should send you some free tools, like FLIR thermal camera, soldering station, etc. etc. Maybe you should create a regular "Mailbag" video.?!!

The 12V rails is low because this is a group regulated PSU. It looks for the 5V to be close. If 5V is not loaded at all the 12V has to be low because it rises with 5V load. This problem is well knowen nowerdays.

Metal Oxide Varistor Sorin, remember not capacitor smoke.

Gorgeous

He fixes it by sense of smell !

you the best

Can MOV's fail with age or has it just been doing its job with small spikes over the last 20 years?

It's probably a Varisor, nd should be replaced, is a protective device for over voltage...

Feeding DC voltage to the DC side of the bridge in correct polarity bridge burns it out

29:00 i had so many times thinking like that, should i plug it or not. On me the things are 50/50 ( OK/Blow)

I want semiconductor vape for my Juul!!

Helloo Sorin, great videos, how to discharge a 480v capacitor?

It is an expensive power supply which you often find in servers or PC racks. With those kind of power supplies it is like a cartel they charge too much money for what it is. They have the power to run graphic cards multiple hard drives and various add-ons they usually live a lot longer than a PC. The oblong shape is to keep them away from other components in a crowded server or PC rack. He could have purchased one from HP at an inflated price.

You really should replace that swollen electrolytic caps, You'll have a bad ripple on your secondary voltages.. That blown component is a MOV, (variable resistor)for handling voltage spikes (resistance goes down if higher voltages are applied).

Nobody: Fireworks Sorin: I Will Speak to My Colleague, He Can Plug It .... super villain laugh [Ha Ha Ha Ha ] best humor I have seen all day

You are comic with it will be a little Chernobyl.cant stop 😁😃😀😂🤪

Tell me Sorin ,do you have a desoldering pump.I noticed that you all component desolder with a copper wire,why?

I like the smell of a burning components it feels that I am high lol

couple for sale on ebay but i guess its a risk if no gaurantee

I think that was a VARISTOR!

Never approach SMPS repair without series connected light bulb!!! (...,or any similar device, such as VFD,....).

That much video for a blown MOV, you know the guy is inexperienced when this happens

That PSU didn't know you can't smoke indoors.

come on out old man and go fishing with me! oh.. there is a second one today... going there..

few people said that im too late to start chip level repair but i study and follow everything i can, but i disappointed these days

I know I'm late around one year, but, it's painful to look someone torturing himself about PSU topology: It's half-bridge, like any ATX PSU, or may be, but rarely, 2-transistor forward , with switch for 110V for voltage doubler, and passive PFC choke. Every capacitor connected in series serves one transistor in pair., for half a PWM period. That blue thing inside heat shrinking material can be interference capacitor in parallel to main electrolytic capacitors. It's simple to check: see the screen on PCB, should be some symbol for component. Check what semiconductors and how many there are, so you can check them first. If fuse was blown, almost 100%b, some semiconductor is broken (voltage or thermal breakdown). In my branch, which is VFDs and DC Inverter air conditioner boards, I always come across the same circuits found in switching power supplies. In fact, every single inverter for motor drive has it's own SMPS with multiple rails, of which are many with different grounds on the low voltage side. As someone already have mentioned, always use series bulb for soft and safe plug into mains. I have my "magic" box with 3 bulbs, different wattages, which can be combined in parallel, for various ranges of converters. If bulbs are turned off after bulk capacitors are charged, then I press switch, which via contactor bypasses bulbs, and plugs full mains voltage into circuit. Also, never work with power converters without variac.

Stop fixing things and come to Australia for visit mate 😁🇦🇺

More Cool..."Nice Smoke.."

you could image the hard drive

Sorin fixing by nose hehe:)

If you don't like fireworks why don't you use a 60W bulb instead a wire to replace the fuse? If there is any short circuit in the schematic, you have light instead fireworks and smoke and nothing is more damaged than in the present

getting high on smokes :)))))))

Never the fuse!!!

Sorin , did you put the soldering iron in you mouth at 24mins ?

Why don't you use a sucker. That suck solder from bord

the guy has never seen a varistor … :D

sir pls my pc is not giving out 5v in the usb port

Smps "switch mode power supply" try it

KA-POW

😍

some one change input voltage 220v to 110v thats why... if i am not wrong

is not worth to repare power supplies since the person who uses this doesn't have a proper AVR to protect it. :/

It's a MOV #facepalm how can you not know it Sorin?

Good night, I'm from Rio de Janeiro Brazil, could you help me? I'm with a source like that, the same on and off soon after, could you help me, I'm grateful in advance.

Hello ....

Sorin, are you drunk little bit ? Otherwise I feel this tutorial . Thanks

Why fix something so old ?

it's not capacitor, its varistor,

"It will work without it", followed by knowing grin......

Sorry its a varistor :)