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View Full Version : Problem with boot up, new psu, anyi deas?



Openingfuel
14-11-2009, 03:29 PM
Well i got a corsair thx 650watt psu today to replace my old one that supposibly crapped out on me ages ago. Anyway it does work apart from the fact that it doesnt boot up my computer.
Here is what it does:
1.When i trick it into thinking that the motherboard is connected it runs the fans, hard drives ect with ease
2.When i try to turn it on using the start button on the case the fans and lights just flick on then straight again they flick off, well better then my last psu i get about a 100th of a second computer time!

So anyone come across this before or can point me to a link. I have also cleared the CMOS by removign the battery several times.

Speedy Gonzales
14-11-2009, 03:38 PM
The on/off switch maybe stuffed / faulty

wainuitech
14-11-2009, 03:40 PM
Sounds like a fault in the board or other components someplace.

Remove the plugs from the front header, short out the two pins that would normally be connected to the on switch with a flat screw driver, see if it boots, could be a faulty switch.

If not then Disconnect all Components that are not required - leave only the Motherboard, HDD, Graphic Card if it has one, keyboard mouse, see if it boots now.

The next step will determin in there is something shorting on the PC -

I would remove all the components attached to the board, as well as the board from the PC, place on a bench, making sure the RAM and CPU are in place correctly, connect the KB/Mouse, graphics/Monitor - PSU - ( nothing else) short out the pins again to boot, you should be able to boot into the BIOS, or at least it will complain about no HDD etc.

IF it still wont boot, remove the RAM - try again- as long as it has an on board speaker it should beep indicating no RAM. If not the board may be faulty.

Openingfuel
14-11-2009, 03:45 PM
Ok ill give that a shot

wainuitech
14-11-2009, 03:46 PM
BTW - can we assume its the same problem as This post , same problem (http://pressf1.pcworld.co.nz/showthread.php?t=104547) ??

Openingfuel
14-11-2009, 04:03 PM
Well it doesnt boot by shorting the pins out and leaving the most important parts so im gona do a bench test of it

Openingfuel
14-11-2009, 04:05 PM
BTW - can we assume its the same problem as This post , same problem ?? well thats when it started but i am getting different results with a new psu

Sweep
14-11-2009, 04:20 PM
Are we sure the CPU is not overheating?

Openingfuel
14-11-2009, 04:30 PM
Well nope still sothing on the bench. The same thing with the fan on the psu just jumping a little bit.


Sweep Re: Problem with boot up, new psu, anyi deas?

Are we sure the CPU is not overheating?

I am sure it isnt because when the pc was working the temps were very low even tho i have been overclocking the cpu to 3.42ghz. The temps were still in the high 30s-low 40s on load and in the 20s idile

Openingfuel
14-11-2009, 04:36 PM
also just tested without ram and nothing. I added the speaker and it didnt make a noise. So if this is right about my motherboard being faulty, how sure are you about that???????

stormdragon
14-11-2009, 04:39 PM
Are you able to get your hands on a known to be good PSU and test it with that?

Openingfuel
14-11-2009, 04:52 PM
No sorry but im sure that this one works as i have shorted it out so it thinks that there is a motherboard and the fans ect stared up fine

Openingfuel
14-11-2009, 08:17 PM
Ok it is my CPU/MOTHERBOARD lol found that out the hardway.I turned on my psu but didnt disconect the 12v thingy from the mobo and smoke came out of the cpu. That cant be good.

Sweep
14-11-2009, 08:20 PM
Are we sure the CPU is not overheating?

So CPU overheating then!

Openingfuel
14-11-2009, 08:32 PM
Sweep Re: Problem with boot up, new psu, anyi deas?

Quote:
Originally Posted by Sweep
Are we sure the CPU is not overheating?

So CPU overheating then!

Idk but what ever it is it smells bad, really bad! Do cpus have poisens in them?????

wainuitech
14-11-2009, 08:37 PM
re Question 10> its a process of elimination - if you know certain components are OK then they can be eliminated hence the reasoning for removing parts not required to get a boot, even into BIOS. Sooner or later you will be left with the faulty part, normally in this case I would bet a Motherboard, as they are more likely to fail than a CPU, unless it was "highly" overclocked and running hot. The Corsair PSU should be OK as it was new. I wouldn't be surprised if the board / or CPU was the cause of the original problem, the other PSU may have been OK.


Look on the light side -

I turned on my psu but didnt disconect the 12v thingy from the mobo and smoke came out of the cpu. That cant be good. Theres the problem - every one knows a PC runs on smoke - let the smoke out and its knackered. :D

Nothing worse than an intermittent fault - as I always say to customers - lets hope the damn part blows, at least that way you know exactly where the fault is.

Edited:
Idk but what ever it is it smells bad, really bad! Do cpus have poisens in them????? Well I wouldn't go sniffing / inhaling it - just make sure every thing has the power disconnected, dont want a fire.

Openingfuel
14-11-2009, 08:40 PM
lol ok thanks for the help!