I need some help. PC wont turn on.

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G

Guest

Guest
Ok here is the deal.

I have a 2 year old dell, wanted to see what socket the cpu was b/c I was wanting to upgrade it. I unpluged all power connectors, took PSU out, took heatsink off, and got the number. Put the heatsink back on, PSU back in, plugged the power connectors, mobo, CD, and HDD, back into place. Once I had eveything hooked back up, I plugged all the cords to the back, mon,mouse,keyboard,etc. Set the case back up, press the on button, but nothing happended.

The lights on the back are working, so is the light on the Mobo.

What do I need to do to find out why it wont turn back on? Any thoughts?

I am not an expert, but do know a good bit about this stuff.
 
Grimmy

Grimmy

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Feb 20, 2006
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You prolly would have got that info you needed from CPU-Z program.

I'd re-go through everything you un-installed. Re-seat the RAM, video cards and such.

Also, you will should reapply thermal grease, since you took off the HSF.
 
G

Guest

Guest
Couldn't find the program to locate socket number. I didnt take out the ram, and the video is built in. What kind of thermal grease, and how do I apply it?
 
G

Guest

Guest
Thanks for the links. Is there anything else I should be worried about? All the plugs are working, and lights are on. It shouldnt be the HDD right?
 
G

Guest

Guest
I did reconnect both the 20, and 4 pin. the fan, hdd, cd rom-only 1, and on switch. Everything is connected the way it should. It has got to be something wiht the cpu.

My cpu is P4 2.6ghz. Not that special, expecially for gaming. Thats why I wanted to upgrade it.
 
U

UC7

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This might seem like a stupid response, but usually it is the simplest of things that screw up a reassembly.

1) Did you make sure that when you put everything back together, the power switch connector for the MB was in place?

2) Did you make sure that both power supply plugs for the MB are connected correctly?

3) Did it not work at all? or did it turn on, and then off shortly after - if so, seating the heatsink and fan correctly can avoid overheating that can cause quick shutoff.

Just some quick ideas. Maybe you have already thought of them.

Heck, by the time I posted this, you already answered some of it.
It seems odd that you cannot even get your PC to POST.
You should be able to turn it on even with the HD disconnected.
 
G

Guest

Guest
Yep, everything is back together. I did not take any hardware out, just the heatsink and PSu. Unplugged the Mobo pins, main fan, and everything else that went with the PSU. The power switch is plugged in, but I think that is the reason, because when I first pulled it out, I dont know why, it made a funny sound.

It does not turn on at all. Not even a second.
 
exit2dos

exit2dos

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Is it a socket 478 (Pins on the chip) or a 775 (Pins on the motherboard socket)?

Either way, make sure there are no bent pins.

Try clearing the CMOS - should be an option in your BIOS setup - if not then there should be a jumper on your motherboard.
 
G

Guest

Guest
Its a 478. I havent taken the cpu out, never have, little too scared. If that is what I have to do, I will try it.

What is CMOS? I cant get into the BIOS because the pc doesnt even come on.

Where would the jumper be?
 
U

UC7

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Here's another quick one...

Is this the same PSU or a new one that you just installed?
If it is a new PSU, give the old one a try again (you dont need to install it, but have it nearby the board.) If it is a new PSU, there is a possibility of an error with the PSU, or maybe a bad wire.

If it is the same PSU as before, it is unlikely that it all of a sudden failed.
 
exit2dos

exit2dos

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Yep, everything is back together. I did not take any hardware out, just the heatsink and PSu. Unplugged the Mobo pins, main fan, and everything else that went with the PSU. The power switch is plugged in, but I think that is the reason, because when I first pulled it out, I dont know why, it made a funny sound.

It does not turn on at all. Not even a second.
Click to expand...

Do you mean the Power Switch header on the mobo? You can try bypassing the switch by connecting the pins with the tip of a screwdriver.
 
G

Guest

Guest
No, its the same PSU, same eveything. I did not install anything new.
 
exit2dos

exit2dos

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Its a 478. I havent taken the cpu out, never have, little too scared. If that is what I have to do, I will try it.

What is CMOS? I cant get into the BIOS because the pc doesnt even come on.

Where would the jumper be?
Click to expand...

What is the model number? Can check Dell's site to see if they have a manual online to show where the jumper is.
 
G

Guest

Guest
By power switch, I mean the cord that leads from the MOBO to the button to turn it on.
 
U

UC7

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Was this power switch connection broken when you removed the connector? It should have 2 metal posts that are sticking up from the MB. Usually these are very close to the connections for the HD LED, POWER RESET.
 
G

Guest

Guest
It was working fine before I unplugged it. I want to make this clear, it is the cord from the MOBO to the button to turn it on.

It is a 9 pin connector. I have 2 on my MOBO, only unplugged one.
 
U

UC7

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That is not the connector to the power button. I am referring to the conection with the wire that leads to the power button on the front of the case. This wire is extremely small.
 
turpit

turpit

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Make sure you didn't forget to plug in the 4-pin power connector on your motherboard.
Click to expand...

Exit!

Another new avatar I see. You continue to amaze me. I had believed for years that I was only one of 5 people who had ever known the Kamp Komedy "Killer Klowns from Outer Space"
 
exit2dos

exit2dos

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Hmmm, you do not have a clear CMOS jumper, only a Clear Passwords jumper (probably the same thing). Instructions for doing so can be found here.

Anyways, I doubt it's your problem. It does sound like your Power Button connection (Or you fried your CPU - did you ground yourself before removing the heatsink?).

The problem with helping you is that Dell uses a proprietary connector to connect the power button and lights to the motherboard - and they don't release the specifications on what pin/wire does what.

The closest thing I could find was for a different Dimension model, so I'm not sure if yours is the same connector:
Dell Dimension Front Panel Connector

In this case, you could connect the two power pins (the third and fourth from the top on the right side) with the head of a screwdriver to bypass the power switch. If the machine turns on, you know it's a problem with your power switch or front panel connector - which you would have to order a new one from Dell.
fpconnla1.jpg
 
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