PC Gurus Needed - New Build PC Will Not Start

[Raging_Bulls]

Sounds like the PC stops during intitial boot of its components, before it enters the BIOS. Do either something is mounted the wrong way or you have a DOA part on your hands.

If the PSU doesn't put out the correct voltage, the PC can shut down during boot indeed. However in that case it should try to reboot on its own until it loses input voltage or gets a clear "off" signal from the motherboard.
Seeing as it does power on briefly, I wouldn't suspect the PSU right away. Perhaps it's faulty, but there are more likely options.

Personally I'd look at the CPU first. Haswell CPUs seem to be DOA a lot more than older models. That being said, did you pay extra attention on the direction of the corner arrow etc? They won't work if they're in the socket the wrong way.

Also, try to boot it with no hard disk. A shorted HDD or a bad SATA cable is all you need to stop a PC from entering its BIOS.

 

[kampos]

Yup ; tried it with no hard drive ; have now swapped about all combi's of RAM sticks and slots. PSU came with the right mains lead and has no voltage select switch. CPU is in the right way ; the cooler isn't standard but isn't the problem I hope. Next step I'll triple-check all connections ; after that it gets drastic I guess ; PSU swaps and so on.

 

[JamesM]

The PSU will have over current protection on its output so if its trying to drive into a short circuit then it may well shut down straight away. Capacitors often fail short circuit and there will be caps across the PSU voltage rails both within the PSU and on the motherboard, and on most things infact.

 

[Raging_Bulls]

Non-standard cooler can't be the problem if you used thermal paste etc. Even if the cooler is faulty, there's no way that this could be thermal protection. As hot a those modern CPUs tend to run, they can't get into triple-digit temperatures that fast from cold.

Just to make sure it's not one of those stupid things : did you connect the 4-pin or 8-pin (depending on MoBo type) above the CPU? Otherwise it won't boot indeed because the CPU doesn't get any power.

 

[secret_squirrel]

A good check for shorting is to assemble all of it outside the case on something non-conductive like a square of foam/esd wrap from the mobo box or a wooden desk.

I presume you have reseated everything?

 

[highlandsflyer]

Remember static when handling things.

Might help to provide a list of components in case any have known issues, but a normal strip back and rebuild testing as you add each item ought to identify the culprit.

 

[PurleySquire]

My knowledge base may be outdated as it's been a few years since I last built a pc, but the older boards used to have jumpers to set various parameters, usually to get the motherboard through POST. If modern hardware still has such things, could one be set the wrong way?

 

[kampos]

Thanks all,will be trying an out-of-case experience once I get home from work. Sure as I can be that everything's seated nicely,depending on results from the above I'm going to tear it down and start again.

 

[secret_squirrel]

If I had to guess I'd say its CPU or mobo related. The behaviour you describe sounds just like early thermal shutdown but as noted is happening too quickly. Might be worth checking that the CPU fan is correctly connected - I have a misty memory of some cpu's refusing to boot without confirming active cooling is connected. Make sure the cooler is 3-4 pin with a pwm (variable speed) controller. Check the cooler is certified for the CPU. Normally I would rule out ram but being a Haskell it probably needs working ram for VRAM to even display bios POSTing.

 

[Kerplunk]

I had something similar recently where I was sure that everything was ok but PC just wouldn't boot. Spent ages troubleshooting taking components out and swapping them for known good ones. Had narrowed it down to the motherboard and gave up and orded a new one as it was nothing special. Half an hour later I happened across an article on the internet where someone had seen the same thing with a similar motherbaord from the same manufacturer (Gigabit). Turns out that I must have had a power surge and the motherboard had shut itself down to save itself. Had to do a full reset of the BIOS to clear the error and it was ok after that.