Power Up Problem

RichardBoult

Active Member
My PC will not power on. When the PSU is plugged into the mains the CPU fan gives a slight spin and a little green light comes on near to the Power Switch and Case LED pins on the M/Board (Abit AT7). Having troubleshooted a bit I am now stuck as to my next move.

I initially suspected I had a faulty power switch but I've tried the Reset switch (which I assume is the same as the power switch) on the power pins and still nothing. What do I need to investigate next the PSU or the M/Board? I had suposed that the little green light indicated the PSU was OK.....

any ideas? Thanks in advance. R
 

mattclarkie

Distinguished Member
If your motherboard power light is on then in theory the problem lies outside of the PSU, unless it is failing to provide enough voltage for the CPU and other components.
 

jetinder

Active Member
When the LED light comes on your motherboard it means power is being supplied to your motherboard.

It could be your CPU, hard drive or ram is faulty.

I assume the motherboard is all connected up to the PC case speaker and I assume ABIT use beeps on power up to tell the user if some thing is wrong.

When you power it on do you hear any beeps ?

Depending on what beep pattern you get you can work out what the fault is.

Check the motherboard manual to see what different beeps mean.

If your CPU, only bootable Hard Drive or ram is faulty this will cause the PC not to power up.

Make sure all the connectors are pushed in.

Make sure the ram is mounted correctly and properly pushed in, with those clips at the side gripping the side of the ram sticks.

Make sure your graphics card is mounted and connected up properly.... as it could be just a loose cable.

Take the heat sink and fan off and check the state of the CPU, then clean and re-apply thermal paste, re-seat the heat sink and fan and power up the PC.

If you have dodgy hard drive or ram, when you power up the PC and if you can see a display on the screen that means the CPU is ok.

If you cant see the screen then its a different and could mean the CPU is at fault (as with out the CPU running, you cant see any display on the screen).
 

Andy98765

Distinguished Member
It could still be the power supply as one of the voltage rails has failed. If you have temp access to another power supply I would suggest swopping out.
I have had two PC's brought to me this year to fault and they had the same problem. Both power supplies were the cheap type that get supplied with a budget case.
 

mattclarkie

Distinguished Member
It could still be the power supply as one of the voltage rails has failed. If you have temp access to another power supply I would suggest swopping out.
I have had two PC's brought to me this year to fault and they had the same problem. Both power supplies were the cheap type that get supplied with a budget case.


The light on the motherboard would make me check that everything is pushed in and looked fine, then if nothing seemed out-of-placed the the PSU would be my next port-of-call because I have heard of the CPU rail going belly-up on many a PSU, and as the Motherboard merely checks for some power and not enough power the light could still come-on.
 

RichardBoult

Active Member
After a bit of searching I suspect the PSU too. I've read that the 5v rail can make the light come on but theres no 12v to make it power up fully. I'm getting hold of a new PSU and I'll post back if that is indeed the fault for reference. (to help others if i can)

by the way I can't find any voltage with a meter!!
 

Blitzmage

Active Member
Yeah don't be fooled that just because the motherboard light is on it isn't the PSU. Infact just a few days ago my machine suddenly turned off and wouldn't even respond to the power button being pushed. The motherboard light and ethernet light was on too. It means one of the rails failed. Had to buy a new PSU to replace the rubbish EZcool

Make sure you get a top quality brand PSU as they should last a few years.
 

mattclarkie

Distinguished Member
Buying a £20 PSU may seem a saving compared to buying a £60-70 unit, but if it causes your motherboard or even your CPU to fail then you have cost yourself alot more than the £40 you may have saved.
 

mattclarkie

Distinguished Member
New PSU, got a green light but still no power up....do I need a new m/board now?

Do you get no activity, or do you get nothing on the screen.


If you get absolutely nothing then maybe it is the mobo.

If it springs to life with no screen then it could be a POST issue.

If it springs to life and then goes dead after a few seconds it could be the CPU over-heating, a component overloading, or the mobo maybe naffed.
 

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