PC - starting problem

[am21]

At first attempt it turns itself off automatically just few seconds after post screen and windows logo. When i keep on pressing the power button / remove power cable and reinsert it starts up again. I have to do the above at least 3-4 times to get the PC up and running. Funniest part is that it works fine once it loads to windows and becomes stable. No heating or any other known issues.

What could be the source of this problem ?

Specs:

E7300 | Intel DG31PR | 4GB DDR2 800 Ram | 250GB HDD | eMARC PSU (genric)

 

[mike1959]

I would try a different PSU, if you have a spare around, as you will soon know if it has found the problem, by booting first time.

 

[am21]

this problem started after upgrading ram (2gb single stick to 4gb dual) but ram is working fine and it shows up in bios/windows etc

i dont doubt the psu because PC is working fine once it loads to desktop... i can even do gaming without a sweat

 

[mike1959]

Yes I see what you mean, the PSU has enough Wattage to power your system once it is running. I was thinking about the 'on' button problem. When you press the button, it makes a transistor circuit switch the PSU on, I think it's that part of the PSU that is faulty, not the actual power output being too low for your components.
Unfortunately, it's not a simple job to troubleshoot a PSU, it's simpler to swap them and see what happens. If it sorts your problem, it's job done.
I have never owned a decent PSU, just the ordinary production Dell types, and a few by 'QTec'.

 

[am21]

other major changes i have made to the system

# on/off switch in the casing was faulty so i had to set reset button to on/off (it was working fine for few weeks)

# upgraded ram

# connected the monitor to psu (19" lcd)

 

[mike1959]

So it is possible that there might be a problem with one of the switches still ?

 

[am21]

@ mike1959: ill ask someone to check the switch in the mean time shall i try to remove the power switch completely and start using a screwdriver (touching both pins) ?

note: i think this is not related.. but might help

all of a sudden my pci wifi card stopped working after the ram upgrade. its detecting fine but cant pick up any signal.

 

[mike1959]

You can bridge across 'pwr' header pins if you are confident about that, but could you try, with the power off, (mains plug out) switch the 'on' switch, on/off many times, say 50 times or so. It might be the contacts inside need cleaning up, and that could do the trick. Or better, can you get a different switch, new or used, to prove if it is the real problem.

 

[am21]

@ mike1959: thanks mate, ill try pressing on/off for sometime and see what happens

its not just on/off.. pc works fine only if i keep the power button pressed for at least 10 seconds and try again or i have to manually remove the power cable and reinsert. just single press doesnt work once the pc turns off at first attempt.. is it something like resetting power ?

 

[am21]

it seems working fine now.. here's what i did

i removed the 24 pin power connector and put it back and also removed and reinserted both ram sticks (swapped slots)

edit: problem started again i have to try around 10 times to boot to desktop but from that point it works normally like nothing happened lol

please read
http://www.hardwareanalysis.com/content/topic/6793/

 

[mike1959]

I have read all the posts in the link you showed.
Still think it will prove to be the PSU, rather than the mains lead/cord.
The only way the mains lead could be at fault is if it was fractured in one or more of the multi-strand wires inside, (highly unlikely) or that the pins on the plug are damaged or bent out of true shape, or the built-in fuse holder was loose, in gripping the fuse. If you have the type of mains lead/cord with the red fuse cover, you could lift it off and check that the fuse is not able to move in the the metal clips inside the the plug. Obviously unplug it from the pc first, there is a fair amount of charge in a PSU after it has been used. If you think the fuse is loose, take the fuse out and squeeze the end clips together with pliers, a few mm's.
Also make sure the fuse and clips are bright metal, clean up contacts and fuse end pieces if any doubt.
As I wrote before, I think it is the control circuit in the PSU that is not switching the PSU on fully, and the posts in that link are saying similar ideas.
If you can run to a replacement, it may sort it out for good.
As one of the writers in the link tried, could you unplug all extras you have on your setup, anything aside from monitor, keyboard and mouse. Run the minimum set up, see if it helps.