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PC will not boot?

December 29, 2020 at 04:44:14
Specs: Windows 10
Hi all,

A few months ago I accidentally turned off the extension cable my pc is connected to and when I turned it back on the PC wouldn't boot. I have tested the AC cable on another device and it was broken - but even with a new cable that I know works, the pc still doesn't boot. I tested the PSU by connecting the green and adjacent black pins together (pins 4 and 5) on the 24-connector with a paper clip (and also a piece of wire) and the fans didn't turn on, and it tripped the fuse for my whole flat. When I plug the 24-connector into the motherboard as normal and try booting, again nothing happens but there is no fuse trip in my flat this time - weird. Is it my PSU that needs replacing?

*update* seems the fuse tripping process burns through the AC adaptors as the second AC adapter now doesn't work either...

Many thanks in advance,

PC built in 2015:
MOBO: MSI H81M-P33 V2, Intel H81, S 1150, DDR3, SATA III - 6Gb/s, PCIe 2.0 (x16), D-Sub/DVI-D, MATX
PSU: EVGA 100-B1-0500-KR - 500W 80 Plus Bronze Power Supply

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December 29, 2020 at 05:02:36
Do you a volt (test) meter?

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December 29, 2020 at 05:37:29
Unfortunately I do not

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December 29, 2020 at 06:32:10
I suggest you get one - ideally get an analogue rather than digital (at least that's my preference).

Amazon have them, as do many local (mom ' pop etc.) electronic parts stores.

This on from is identical to one I bought from Radio Shack - aeons ago; simple reliable and inexpensive, and perfect for general use.

ChgImposs Analog Multimeter Electric AC/DC Current OHM Decibels Voltage Voltmeter Ammeter with Test Leads

Then you can test the psu to see if it's delivering "any" volts...?

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December 29, 2020 at 06:46:38
Even a "bargain basement" digital meter from Harbor Freight would work:

"Channeling the spirit of jboy..."

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December 29, 2020 at 06:54:29
Ok I'll get one thanks, then I just put one connector on pin 4 and one on pin 5 as I did with the paperclip?

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December 29, 2020 at 09:10:42
The meters come with test leads - pointed ends and add/slip on crocodile clips.

Just be careful not to short two adjacent pins together when testing/checking for volts.

The Amazon meter costs a penny under $10.;and I suspect the suggestion by T.R.A. will be much the same.

Useful to have even a basic meter around at any time.

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December 29, 2020 at 10:31:56
"...and I suspect the suggestion by T.R.A. will be much the same."

$6.79 (US). They used to be free coupons for them, though I haven't seen any lately. As always, ditch the 9V battery that comes with it and put in something of higher-quality.

Think I already mentioned this in another post, but I had one of the HF (freebie) meters at a former job. Guy from a calibration lab came every year to calibrate our test equipment and standards. For kicks, I asked him to check out the freebie HF meter (thinking it'd be so far off that it'd be pathetic). He said it calibrated closer than any of the Fluke meters we had in-house...

Kinda scary when you think about it ($0.00 Chinese meter wins over +$300.00 Fluke meter).

"Channeling the spirit of jboy..."

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December 29, 2020 at 11:40:01
Likely the Chinese reverse engineered the Fluke and similar, made minor changes/improvements and then set out to sell it cheap. The end goal - put the non Chinese companies out of business and thus take over the market - and ultimately the global market place and so on...

In the 1930s Japan was considered to be doing similar for the time; and the goal of the government of the times was - well.... history tells all. China is effectively repeating history

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December 29, 2020 at 12:37:48
For information, this link shows the EVGA voltages (and the paper clip test you've already tried):

Some more info:

Most likely the PSU itself has failed.

What do you mean by AC Adapter? Laptops have those but PCs just have a simple power cord. If that's what you mean then a faulty PSU might be blowing the plug fuse (UK). If so replace with a 3A plug fuse.

Always pop back and let us know the outcome - thanks

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December 29, 2020 at 14:28:12
Based on the fuse for the whole flat blowing... I'd be inclined to share Derek's view; that whatever you did with the paper clip experiment possibly shorted the psu - which hath now died in the process - and that tripped the flat fuse?

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December 30, 2020 at 09:01:16
Thanks all, appreciate the help.

Replaced the PSU with a new one and PC is working fine now. Have ordered new fuses for power cord plugs - @Derek yeah i just meant these kettle leads:

I used 2 kettle leads with the old PSU and both no longer worked afterwards - will replace their plug fuses.

I've order a multimeter to test the old PSU; my PC was very dusty inside - I hadn't cleaned it since I built it in 2015. Don't know whether this could have caused the PSU to fail or just 5 years of age? Have taken out big clumps of dust and am looking for a can of compressed air to get rid of the dust - tempted to just use a hair dryer, if not carefully with a hoover.....


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December 30, 2020 at 09:32:48
Some of the computers I work on are horrendous inside. It's not uncommon to find something like this:

The dirt & dust degrades fan bearings & causes overheating. At the very least it prevents heat from dissipating from components & shortens their lifespan. So if your PSU was loaded with dust, that's probably what led to its early demise. A word of caution - do not use a vacuum. Static can build up in the hose & then discharge & fry components. Blow the dust out & then vacuum up the mess afterwards (before the wife sees it).

I clean my personal tower(s) about twice a year. Sometimes I use canned air, other times I disconnect everything & take the tower to the garage to give it a good blast using my air compressor. I always wedge something in the fan blades 1st so they don't spin out of control.

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December 30, 2020 at 09:33:18
re' the meter posted by T.R.A.

In the UK it's sold direct via eBay (UK site) for anything from £6.77 upwards.... And then there's the shipping etc. - and possibly customs/sales tax on top...; which can be double or more the price of the actual meter itself.

As is so often the case... anything which crosses the pond after being (or is still) sold in Canada/USA - the currency symbol changes to £ from $ - at least; or even more common they up the price even more as well.

Any thoughts on their clamp on meter?

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December 30, 2020 at 12:22:19

Glad to hear you got it sorted - thanks for feedback.

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