Built PC - wont turn on

Soldato
Joined
7 Sep 2009
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Cheshire
Just put together a s775 pc for someone, and despite the mobo power led coming on when I turn the PSU on, pressing the case power button does nothing. I've made sure the power molex is on the right pins, and obviously the PSU 24 and 8 pin connector are plugged to the mobo - ideas?
 
Have you checked that the power switch is connected to the mother board correctly? I once put them the wrong way round and wasn’t able to turn my comp on.
 
Agreed. Usually I short the connector with a screwdriver to check it boots properly before pluggin in all the case connectors.
 
How do I properly short the connectors? What needs to be plugged in/on when I do so?

So long as the basics are there its fine. Its not a dangerous short or anything. I just run a screwdriver tip over the connecters so two of them connect.
 
okay so I just ran a screwdriver across the 2 pins and nothing happened, despite mobo light shows it's getting power still? Is it likely a case of faulty connectors/mobo?
 
Try reseating the RAM and only plug in the bits you need just to power it on, to narrow it down i.e only have RAM,CPU and power connector
 
Yeh I've just tried each stick of ram individually as well as disconnecting everything else like gpu, hdd, fan controller etc, still no luck, the power cable is working fine too, leaving me to think its still mobo or less likely psu. I'll try psu on other machine. Could it be the case mounts causing the board to short?
 
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okay so I took it out of the case and just had the ram/gpu connected and used a flathead to short the power and the board posted and ran fine, so I'm guessing it's the case shorting the board, how can i solve this?
 
okay so I took it out of the case and just had the ram/gpu connected and used a flathead to short the power and the board posted and ran fine, so I'm guessing it's the case shorting the board, how can i solve this?

Make sure all the pillars underneath (what you rest the motherboard on) are aligned with the holes and make dont screw it down tight, also make sure the screws are not touching the motherboard (they should be within the metal edge you get around the holes or use those lil plastic washers to stop this also)
 
So I tried it in the case again, without any washers and it worked this time :S oddly enough i think it might have been because last time I didn't bother with 1 screw that was in a fiddly place, and knowing the case grounds it, made sure to use all of them this time. Either that or I failed miserably at lining it up last time lol
 
There are loads that can go wrong with a build, that can easily be fixed.

This mini guide may help a little - http://www.buildyourown.org.uk/pc-building/troubleshooting/

Google for a "motherboard test kit" that will give you the switches and a speaker you will need, which can help you easily turn the machine on, check things are working, and get the system to POST.

Good luck.

EDIT: Just seen you are sorted, nice one. With my first build, I was switching the machine on, but it just wouldn't load up at all. The fan spun for a few seconds, then would turn off straight away. I took the machine apart (I did test it outside the case before), thinking a short was caused that problem.

Turns out, in my complete n00b wisdom, I was actually turning the PSU off (not on) and it was being powered by the residual power left in the system :D So when I turned it "off" (actually on) it gave a little bit more power into the system, meaning when I turned the PSU "on" (actually off) it would power the LED's and the fans for a few seconds :D Felt a right idiot afterwards, haha.
 
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So I tried it in the case again, without any washers and it worked this time :S oddly enough i think it might have been because last time I didn't bother with 1 screw that was in a fiddly place, and knowing the case grounds it, made sure to use all of them this time. Either that or I failed miserably at lining it up last time lol

Amazing what hassle a little screw can cause! :D
 
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