Is a PSU blown after turning on a computer with the switch on "O"?

[haiperspet]

I've made a huge mistake and turned on another computer after putting it back together with the PSU's switch on O. What happened when I turned it on is that the PSU started sparking and smoking. Is it safe to assume that the PSU is blown and that I'd need to get a new one?

 

[Gingerbread]

If it started smoking and sparking I would say its toast. Highly unlikely it survived damage of that level.

 

[smorizio]

you need to get a new unit and a pair of clean shorts too. hopefully all you did was kill the power supply and no other part. you have to look now for any other melted part in your pc. a pc supply should not do that if the supply is on or off. only time a supply will spark is if there a dead short.

 

[haiperspet]

Thank you guys. I made a dumb move on flipping the psu switch again to an open connection instead of closed. Hope the rest of the components are safe too.

EDIT: Everything else looks good. The PSU is definitely dead, pieces fell out from the fan when I took it out from the case.

 

[Darkbreeze]

Your problem isn't due to where the switch on the back of the PSU was set to. You should be able to power on with that switch in either position without it causing any problems. In one position, it should start the system. With the switch turned to 0, it should do nothing. You have a bigger issue somewhere else, not where you have the switch set to. That doesn't matter at all. Something is shorted out or you have a really, REALLY crappy power supply.

And if you were still assembling the system and didn't have things fully plugged in yet, the power supply shouldn't have even been plugged into power at all.

 

[haiperspet]

Everything was plugged in correctly, there wasn't anything else I can find to not plug in.
The PSU was quite old, opened up the PSU case from the top and there was a smudge and something melted on it. Then there was some black ooze in the PSU according to where the smudge was at. Not to mention, it was extremely dusty inside.

I was turning on the PC to setup the BIOS, and made sure everything was plugged in.

 

[Darkbreeze]

Well, looks like at the very least you need a new PSU. Good luck.

 

[haiperspet]

Any recommendations on PSUs?
I calculated a basic setup for recommended wattage using eXtreme PSU Calculator:

XOV PSU Calculator component list

Motherboard: Desktop (micro ATX)
Socket: Socket LGA 1150
CPU: 1 x Intel Core i5-4460 3200 MHz Haswell-DT
Memory: 2 x 8GB DDR3 Module
Video Card: 1 x AMD Radeon R7 370
SLI / CF: Yes
Storage: 2 x SATA 7.2K RPM
Load Wattage: 287W
Recommended Wattage: 337W
Note: Standard keyboard, mouse, and 8 hours of computer utilization per day already included in calculations.
Generated by eXtreme PSU Calculator 2016-06-15 03:30:16

So something about 400W, but preferably 500W+?
The one that I had is 550W(The one that shorted).

 

[Darkbreeze]

Recommended capacity for the R7 370 is 450w.

Forget about calculators, these are trustworthy specifications based on real world testing aimed at safely meeting capacity requirements AND putting you in the correct ratio for efficiency at any given capacity.

http://www.realhardtechx.com/index_archivos/Page362.htm


What is your budget for a new power supply?

 

[haiperspet]

Reliable and decent costing, likely $125 or less. I didn't expect my PSU to get busted up, and I'm seeing some decent sales on newegg:

$60 Rosewill Valens-500M, Valens Series 500W Modular Power Supply, 80 PLUS Gold Certified, Single +12V Rail, Intel 4th Gen CPU Ready, SLI & Crossfire Ready

$90 Rosewill Photon-750, PHOTON Series 750W Full Modular Power Supply, 80 PLUS Gold Certified, Single +12V Rail, Intel 4th Gen CPU Ready, SLI & Crossfire Ready

$85
Rosewill Hive-850, Hive Series 850W Modular Power Supply, 80 PLUS Bronze Certified, Single +12V Rail, Intel 4th Gen CPU Ready, SLI & CrossFire Ready

I may get the 500W for the price.

 

[Darkbreeze]

TBH, every one of those units sucks. This would be a FAR better choice and did Silver in JonnyGuru testing. This unit is made by Super Flower for EVGA based on the Golden Green platform. Very good unit.

PCPartPicker part list / Price breakdown by merchant

Power Supply: EVGA 750W 80+ Bronze Certified Semi-Modular ATX Power Supply ($64.99 @ Amazon)
Total: $64.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-06-15 04:05 EDT-0400

If you prefer or require that it be fully modular, instead of semi-modular, which is entirely unnecessary unless you have plans to individually custom sleeve each cable, then this would be a great choice:

PCPartPicker part list / Price breakdown by merchant

Power Supply: EVGA SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($89.99 @ Amazon)
Total: $89.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-06-15 04:08 EDT-0400

 

[haiperspet]

Seems good. Thanks for the help!

I have no idea on modding anything, so I'm leaving all parts as is.

 

[Darkbreeze]

Then I'd go with the B2 750 semi modular unit. It's got a good warranty, is very reliable and is extremely quiet and well built.

 

[smorizio]

also xfx power supply are rebranded seasonic units. they have good sales some time that are better then evga units.

 

[Darkbreeze]

Yes. Most XFX are good units. They are not all Seasonic however. XFX has some Shenzhen Ruishengyuan units now that are based on Seasonic designs but not built or QA'd by Seasonic. Reviews of these units are less than fantastic.