pc not turning on

[nickb]

my pc was working fine this afternoon, i left it on whilst i went and did something else, it went into standby mode. i then came back to it, the standby lights were on but nothing worked, i couldnt get it out of standby mode. I turned it all off at the plug and tried to turn it on again, nothing. there is a light on the motherboard when the power is on, i have changed sockets and power cables, nothing. Any help would be appreciated.

[Plastic Nev]

Hi and welcome to Extreme Tech Support - Free PC Help.

 

Can you please tell us the make and model of your computer if a manufactured one, or if a custom built one the motherboard, power supply, processor and anything else you know about it.

Also is this a desktop computer or tower type, or is it a laptop?

 

With initial thoughts and information, there could be any one of several problems, however first to check will be the power supply. Although lights are showing, are any fans running? Power supplies have several different output voltages so it could be the lower voltage section that may have blown.

 

Are you at ease working inside the computer and of course taking anti static and other safety precautions?

 

Nev.

[nickb]

hi. its a tower i had made. its got an asus m5a78l-m motherboard, amd fx 4100 3.6ghz cpu, pulse 700w psu, running 12gb memory.

 

i replaced the psu this morning with one i know was working, nothing.

[Plastic Nev]

OK, If you are sure the PSU is OK, next thing to check is the RAM memory, I assume there is more than one stick or card of memory, so first remove all of them, then put one back in and try it and see if it will boot up, if not, take that one out and try the next till all have been tried.

 

You didn't say if all fans start up, can you answer that one please.

 

Let us know what you find.

 

Nev.

[nickb]

ok i will try the memory next. nope none of the fans start up

[nickb]

all the memory has been tested, nothing still

[KenB]

none of the fans start up

This is either the motherboard or the PSU.

 

You say that you have put in a second PSU with the same results ?

If this is the case then you have to suspect that the motherboard has died.

 

I would be inclined to test the PSU first.

There is a tutorial here - click here

You will need a volt meter or multi-meter to do this.

 

You could also try stripping down the hardware etc from the motherboard .....

down to just the main power connection from the PSU.

click here

 

Do you get any POST beeps ?

No beeps ( if you used to get one ) indicates a PSU or motherboard problem.

[nickb]

yeah i tried a psu from another pc i have and nothing worked. i put it back in the old pc and worked fine. So im suspecting the motherboard must have gone. Looks like a new board then, not what i wanted to buy just before christmas but needs must!

 

thanks for the help

[KenB]

Just to make sure - use my other link to "no POST beeps" and strip the main connections off the m-board to see if you get the same problem.

If you do .... no POST beep / no fans running .....then it looks like a dead motherboard. :(

[Plastic Nev]

Hi try that check on Kens link as it just might be something such as a major fail of for example the CD drive which if gone short circuit, it will hold all the power off.

 

However, if that check proves that nothing happens after doing the disconnections and therefore is the motherboard, once the board is out, check the circuit tracks round the base of the main power connector.

I have heard of the connection to one of the pins burning through.

It was fixed with some careful cleaning and soldering.

 

Nev.

[nickb]

yeah just done that test. No beeps, no fans, no lights

[Plastic Nev]

OK, it certainly looks to be the motherboard died, first check before taking the board out, (You will have to any way) Have a look at all the metal canistered capacitors, any showing bulges on the tops or signs of chemical leakage underneath?

Blown capacitors is one of the known causes of failure, usually damaging many other components so not worth trying to repair.

 

If there are signs of that, or burn outs, at least you know what caused it, even if it means a new motherboard.

 

Nev.

[nickb]

i will have a look when i take it out. wont take it out until i have a new one, then i can double check where everything connects too.

 

next question is which board to get? i could just get the same one which is good enough for what i need now, or maybe upgrade abit. Any thoughts? At the moment i have this board https://www.dabs.com/products/asus-am3--amd-760g-ddr3-uatx-7MMB.html with this cpu https://www.dabs.com/products/amd-fx-4100-am3--3-6ghz-12mb-95w-7R41.html. so would want one to fit that cpu. It also must have 4 slots for RAM. vga and dvi-d connections, and at least as many expansion slots as my current one.

[Plastic Nev]

Hi, one thing we don't yet know is which operating system do you have installed on the hard drive?

 

Next question has to be, have you a means of connecting the hard drive to your other computer, just so you can check out that the hard drive is still OK and not become a domino of the motherboard failure.

 

Thirdly, and the reason for asking which operating system is the fact that Windows itself is fussy about the hardware, especially the motherboard. If you change like for like, then there will be no problem, however if a much different motherboard, Windows might refuse to boot.

The older Windows XP was especially so, however Windows Vista and Windows 7, aren't quite as fussy and may allow a motherboard slightly higher in spec and is a board based on the original.

 

With a major motherboard change and difference it can mean reinstalling Windows with consequent loss of all your data as a worst case situation.

 

Nev.

[nickb]

its running windows 8.1 64bit.

 

im really hoping that my hard drive is ok, i will be really annoyed if its not, i had a good football manager game saved on it!

[KenB]

Your best bet is to swap like - for - like re. the motherboard.

As Nev has suggested ...you may swap the motherboard and find that it will not boot up anyway.

 

I assume that you do not have an install disk or drive image ?

 

If you are taking the CPU out of the old m/board and have to remove the heatsink ..you will need to clean off all of the old thermal paste.

Use rubbing alcohol from a pharmacy.

Then replace the thermal paste with a small amount ...about the size of a pea.

Spread it with a plastic credit card or similar.

Too much is as bad as not enough.

[Richard_T]

Good luck with the repair, I had a similar problem here http://extremetechsupport.com/threads/16587-And-then-it-all-went-of#.VI4KYHvLKlI

the Dead psu was tested using a psu tester, and the rest of it ( graphics card etc ) were tested on a donor - ie old p.c

If you dont have the windows install disk, or your version of windows is an oem one then a like for like replacement may be in order.

 

Even though I have a full retail version of windows it had to be activated for the new mother board using an automated phone thing, keying numbers in different boxes (1-9) then having another set of numbers to put in another set of boxes read out

[nickb]

well i contacted the company i bought the parts from and they told me to send the motherboard to them to test. Which i did and sent the cpu too, they sent me an email a couple of days later saying they had refunded for both parts, didnt say anything else. the new parts have just arrived, installed everything into the case and went to press the on button, not alot happened! there was the lights for a second then nothing. opened it up to make sure everything was connected properly, it is, so turned it on again with the case open, lights came on and all the fans turned (1 on the psu, 1 on the cpu and 1 on the case) for a second then went off. tried disconnecting all but the motherboard and took the memory out 1 by 1, same thing.

 

what to do now?

[nickb]

well ive found the problem. looks like i tightened the motherboard abit too much :( loosened it and it seems to boot fully

[KenB]

Hi Nick

 

looks like i tightened the motherboard abit too much

I would be inclined to check the stand-offs ( what the screws you are tightening are attached to. )

It is probably one of these shorting the case to the underside of the m-board.

 

At least you found the problem :)

[Plastic Nev]

I would take the new board out completely and as Ken suggested check the stand off's and compare them with the fixing holes on the motherboard, there is a slight chance that there is a stand off with no corresponding hole in the board.

It may have been used for the old board, however a modification in design of the new board may now finish up with a circuit track shorting to it. If that is what you find, remove that now redundant stand off.

 

Nev.