New mobo,cpu probs

popcorn1066

popcorn1066

popcorn1066

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8 Aug 2009
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Am upgrading my system for the umpteenth time with a new cpu, mobo and ram but have run into a problem:

When i built everything, the computer would turn on for 1/2 a second and then stop, can't get anywhere.

Stripped everything out and am currently running the mobo on a piece of cardboard with just power and power switch plugged in - same results.

Looking on google, suggests psu faulty, but have tested it with old mobo and it's fine. I'm guessing either the cpu or mobo is faulty but I can't tell which.

Has anyone come across this b4 - it looks like a late night.

mobo is asus m4a785td
cpu phenom 2 x3
ram corsair ddr3 2gb
 
Does it beep with ram removed? Does it beep with the gfx card missing? Does it beep if the only things present are the mb and psu? Needs a speaker attached obviously

That the psu works with another system doesn't mean the psu isn't faulty, it just makes it a bit less likely to be faulty. From most likely to least likely, the problem could be:

You've connected it together wrong
Faulty motherboard
Faulty PSU
Faulty ram
Faulty monitor
Faulty processor

You haven't said what psu it is, if it's a rubbish one I'm moving it to more likely to be faulty than the motherboard. Processors tend to be bombproof, but I have killed one so they do fail
 
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All power connectors connected inclucding the 4 or 8 pin for cpu power, often gets missed :)

Tried single sticks of ram.
 
PSU is aerocool, think it was 500w

At the moment, out of the motherboard, there's only:
ATX power connectors both 24 & 4 pin plugged in (manual says I need both)
1 stick of ram
CPU
heatsink fan cabl connected to mobo

so this is really down to the bare mimumu, and still won't start.

I will try and borrow a psu from someone tomorrow and see what happens though.
 
So,
Does it beep with ram removed? Does it beep with the gfx card missing? Does it beep if the only things present are the mb and psu?

You do need both 24 and 4 pin. That's the bare minimum to run, not the bare minimum for diagnosis. You're trying to get error beeps out of the motherboard as a sign of life.

I point my finger at the psu. I don't know aerocool personally so this may be unfair. It's not one of the standard recommended 'good ones' which increases the chance that this is the problem. If the system doesn't work with a second psu, the next one on the list is the motherboard. I hope you bought it from somewhere with a good rma policy, asus can be terrible
 
no beeps for anything, I think it only supplies power for a millisecond and then shuts itself off. I've tried various combinations, graphix is on board, so haven't plugged in a graphix card.

I'm starting to hedge towards the psu problem, as my psu lights up, and what seems to happen is that it tries to start, then I hear a click from the psu, then it all shuts down although it seems strange that one mobo is fine, but this one isn't. I think I'll go and take a long bath, then borrow a psu tomorrow and see what happens. At least I can still plug in my old mobo & cpu and still have a computer.

One day they'll make plug and play for everything in a pc :)

Will let you know tomorrow - thnx for the help though, it's much appreicated. I used to use custom pc forums, but after they started messing around with their web-site I've migrated over to overclockers - and I'm much impressed by this place.
 
This, from the thread, seem much more likely to be a mobo problem than a psu issue (as it works fine elsewhere). Is the mobo under warranty?
 
just a silly one, but did you enable on-board VGA before installing the new gear? if you were using gfx card and disabled on-board VGA prior to this, and forgot to re-enable it, you might have problems booting up without any VGA.
 
mothermachine said:
just a silly one, but did you enable on-board VGA before installing the new gear? if you were using gfx card and disabled on-board VGA prior to this, and forgot to re-enable it, you might have problems booting up without any VGA.
Click to expand...

It would still POST though - there simply wouldn't be any display and he would just need to clear CMOS.

If the PC shuts off after a couple of seconds then I'm inclined to think motherboard if the PSU has already been ruled out. I'd expect it to stay on and not POST or POST beep if it was RAM related.

I'm having my own personal nightmare with my new build at the moment :mad:
 
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