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A blank screen appears if when the PC is turned ON

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November 26, 2010 5:25:06 AM

Initially while playing music on my PC via VLC player, the screen went blank and music stopped. then I had to restart the machine an then it worked properly. this thing happened for many times and now the problem is that when I start my PC the cdrom and the fans turns on but there is no display on the screen.I also confirmed that the screen is working well.Then what can be the problem
Please help me urgently as I have some important data to be retrieved from my PC
Anonymous
a b B Homebuilt system
November 26, 2010 10:53:35 AM

This topic has been moved from the section Forum Feedback to section Systems by Grumpy9117
a b B Homebuilt system
November 26, 2010 4:10:30 PM

Welcome, Newcomer. First, please post the components of your build. Next, reduce the load on your PSU by disconnecting anything that isn't important for a POST. All you need is the following:

1. PSU plugged into mobo
2. CPU and Heatsink w/fan plugged in
3. One stick of RAM
4. Monitor connected to onboard VGA or GPU (if mobo has VGA, use it instead of GPU)

If you disconnected the front panel from the mobo, jump the PWR_SW pins on the mobo to turn on your computer.

If you didn't disconnect the front panel, and you're still experiencing no display, turn off system and disconnect front panel. Try again.
a c 122 B Homebuilt system
November 26, 2010 8:51:42 PM

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beeps patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. You do have a case speaker installed, right? If not, you really, really need one. If your case or motherboard didn't come with a system speaker, you can buy one here:
http://www.cwc-group.com/casp.html

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.

Motherboard LED's mean very little. When on, all they are telling you is that the computer os plugged into a live power socket and the PSU is switched.

Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
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.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

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 or long single beeps indicate a problem with the memory.

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.

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.
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