My PC made a very loud buzzing sound and then emedieatly shut down and wont turn back on

[Cheeseburger203]

Yesterday I installed a new psu and graphics card and it was working fine but half an hour ago it made a loud buzz and emedieatly shut off, I turned off the power supply and unplugged it and by this point I noticed the smell of melting plastic, I opened up the case and took a look inside but everything looked normal (no melted plastic or exploded parts, etc.) The graphics card was extremely hot and so was the CPU. The 12v CPU cable was also very hot. Is there anything I can do to salvage it? What did I do wrong? What happened? I have no money to replace anything like a motherboard or CPU but maybe I could afford a new psu. Is there anything I can do?

[Himommies]

Well I wouldn't use that PSU again.If your lucky a new one should fix the problem

[PlayStation 2]

...can I ask what PSU you had?

[Turtle Rig]

1 minute ago, handymanshandle said:

...can I ask what PSU you had?

Has to be PSU,  It died.. sighs

[Aimi]

17 minutes ago, Turtle Rig said:

Has to be PSU,  It died.. sighs

Of course it's the PSU, but he's asking which brand/model.

[Cheeseburger203]

16 minutes ago, ReggieGRS said:

Hopefully it didn't fry your parts. What were you doing when it happened? Was the PC under heavy load like gaming, rendering and stuff or was it idling or browsing?

I was playin rainbow six siege

[Cheeseburger203]

1 minute ago, Aimi said:

Of course it's the PSU, but he's asking which brand/model.

Its a kentek 680w, I forget the exact model

[Cheeseburger203]

22 minutes ago, handymanshandle said:

...can I ask what PSU you had?

Kentek 680w

[Billy_Mays]

1 minute ago, Cheeseburger203 said:

Its a kentek 680w, I forget the exact model

First mistake, buying a brand without much recognition. Second of all Most power supplies arent 680w thats a super uncommon wattage, its typically 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 1000, 1100, 1200, 1300. Those are the common wattages for power supplies. What are your exact specs too?

 

[Turtle Rig]

10 minutes ago, Cheeseburger203 said:

Its a kentek 680w, I forget the exact model

Never heard of that company no wonder this happened.  

[aezakmi]

3 minutes ago, Cheeseburger203 said:

Kentek 680w

F

that thing was probably 300W or 430W at max with low amperage

just hope the card wasn't fried

 

my version of the autopsy: overload, the hot cables indicate overcurrent during a mild extended period of time and a transformer failure (as opposed to a short where the current spike doesn't lasts enough to get the cable hot because SCP kicks in)

smell comes from burnt cables at the hottest point that is the connection between them and the PCB inside the unit, conductor gets hot and the cover melts, some emit smoke and some don't depending on the material

 

[Gareque]

Honestly speaking, only ever buy PSU from well known brands.

 

Personally, I stick to Corsair or EVGA.

[DavidKalinowski]

I've had good luch with antec and raidmax (though many people say raidmax isnt that good. I've had mine for like 5 or 6 years and i've even cut and spliced wire to make the cables longer and what not...)

[perkyzombie]

I recently purchased Kentek because curiosity, mine is rated at 550w however the rating which interested me is the 5 volt rail at 40 amps. This is relative for P3, P4, Athlon XP systems. The 3.3v and 12v rails are only rated to 25amps, which is likely low on the 12v for modern gaming systems. Indeed a quick look at the rail specifications for the Kentek 680w, this is truly meant for the last of the 32bit systems, see picture, only 22amps on the 12v... that's why it blew on a modern system.

 

After opening the 550w unit it is clearly a knock-off, I suspect the PCB is copied for an Enermax or SH circa 2002ish. However, all the AC interference suppression components were not populated and only the minimum of the electrolytic caps are populated. The PSU is a basic full-bridge rectifier with near no power conditioning.

 

Admittedly, I'm quite the Corsair fan boy as I've six systems using their PSUs, 5 of which are the HXi series. I've not bothered or had the need to crack any of the HXis open and my only gripe regarding things Corsair is the complete lack of linux support but that's just typical and irritating.

 

However(!), the sixth PSU is an older TX750W which had two issues. The axial fuse on the AC supply had a cold solder joint on an axial lead which eventually failed. This cause intermittent operation and the typical zzt sound as the connection went in and out of contact; easy fix.

 

While I was poking around the PSU looking for the failure I desolder the AC film capacitor which is used for interference suppression. Not impressed here, these are the cheapest of the cheap, China X2s. Likely, the PSU experienced an overvoltage event which can really wreak havoc on film caps; mine was operating at 60% capacitance. I'm a huge fan of the Panasonic film caps as they have a fused grid array which limits breakdown propagation. I use these on all PSUs I refurbish (as well Nichicon PM or PW series electrolytic caps for PSU and motherboard power cap replacements -good high ripple current and ~0 ESR)

https://industrial.panasonic.com/ww/products-cap/film-capacitors/film-cap-electroequip/radial-features

 

The better the interference suppression the less the AC leakage into the DC supply and the less ripple current the motherboard caps have to deal with as well swtiching transients. Modern motherboards which are somewhat decent have all made the switch to polymer caps in lieu of electrolytic caps, polymer caps have ripple suppression ratings typically five or more times higher than the equivalent sized electrolytic as such they are far more tolerant to crapy PSUs... they are also 5 times the cost.

https://www.tomshardware.co.uk/power-supplies-101,review-33299-3.html