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Upgraded PC wont start, fans turn immediately off

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Last response: in Systems
March 4, 2011 11:17:55 PM


So i just bought some new components for my PC:

- Motherboard: Asus P8P67 LE 1155 socket
- CPU: i7-2600k 1155 socket
- Western Digital caviar black, 2TB 64mbit cache, 6gb/s

These components as mentioned above i put together with these ones that i already had from before:

- Graphic cardt: Geforce GTX 295
- PSU: Corsair TX 650W
- Memory: kingston 1333 MhZ pc-10600, 6gb
- Corsair H50 watercooler
- Samsung SpinPoint F1 500GB SATA2,
- Antec twelve hundred big tower

When i was finished with putting it all together, my PC wouldnt start. At once i tried to turn it on, i saw the fans started to run, but under a second it was turned off again. I assume the whole system turns on for about a half second and then off again. My motherboard little lamp always turns green at once the power is connected.

I might have connected something wrong, but i think i have been accurately with them. I am also pretty sure i have connected the power swith pins right. But maybe im wrong.

I thought first i had connected the motherboard to tight, i also checked for additional screwslots beneath the motherboard, if it was touching stuff it shouldnt.

My PSU worked earlier today on my old system. So it would be weird for it to just stop working now. I think i have connected something wrong but i have no clue what is. I may simply have just done a common mistake. Im to afraid to experiment to test over again several times, i dont want to damage any components.

Any thoughts for what may be wrong? :/  I really appreciate any answers!

More about : upgraded wont start fans turn immediately

a b B Homebuilt system
a c 117 V Motherboard
March 4, 2011 11:37:30 PM

Your post suggests that there is a short. Breadboard your system:

1. Remove all connections/hardware from the mobo, except for the CPU/HSF
2. Remove the mobo from the case
3. Place mobo on a non-conductive surface (wood, cardboard, etc)
4. Install one RAM stick (check your manual for placement)
5. Reconnect the PSU, both P1 and P4 connectors (remove PSU from case, if need be)
6. Install your GPU and connect the aux power cable, and connect monitor
7. Using a flathead screwdriver, or similar tool, jump the PWR_SW pins on your mobo

Does your system stay on now?
a b V Motherboard
March 4, 2011 11:49:32 PM

I would check the header wire coming from you case to see if they are all in the right spots. And check to make sure you plugged you cpu power plug in.
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March 5, 2011 12:16:25 PM

CopaMundial said:
In the 'Systems' forum, in the top sticky you will find these two links useful as a checklist of things to review.

3. Troubleshooting

PERFORM THESE STEPS before posting about boot/no video problems!

4. Guides for PC Building
Step-by-Step Guide to Building a PC http://www.tomshardware.com/forum/274745-31-step-step-g...

I have followed all these steps before i started the computer for the first time. I have Hot-wired my PSU, and the fans in my case worked like before. So its not the PSU thats broken. I think its just protecting from overvoltage, but i cant find the source!
a c 122 B Homebuilt system
a c 157 V Motherboard
March 5, 2011 2:26:44 PM

The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

Breadboard - that will help isolate any kind of case problem you might have.

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
March 6, 2011 4:50:32 PM

I have breadboarded my PC. Everything works when the motherboard is on a plastic plate outside the case. But i have only tested it with the CPU fan that was in the package of the new CPU. I left alone the corsair H50, and removed the bracket on the backside of the mobo. I will test now with the Original CPU fan while the mobo is in the case. I fear its the H50 thats causing overvoltage (short) that prevents my system to boot. But the bracket is made of plastic, so i cant see how its happening.

Can it simply have something to do with that the bracket is diagonal and causing it to touch the small sharp metal things under my motherboard? (I have no clue what the sharp small things are called on the back on the motherboard) Im norwegian, my english isnt perfect.
March 6, 2011 5:27:07 PM

It looks like i have connected wrong in the Channelfan_1 connection. Once i took it out, my pc started like normal (inside the case). Im not sure why it causes malfunction, its a 4 pin connection that i connected with a wire from the PSU, that has several other connections for the cases fans. I will still see if it will turn on normal with the H50.
March 6, 2011 6:27:41 PM

Looks like it all working again :)  Such a little mistake cause such a huge problem. But thanks everyone for the assistance! Sure learned alot