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Computer not Booting

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October 2, 2010 8:12:08 AM

Hi!

I am trying to fix my dads computer and its not going too well =/.
Here are his specs:

ASUS P4S800 (Old, 478-socket)
Pentium 4 HT
idk gfx card
idk ram, though its 1gb ddr1
HDD is a Maxtor(IDE)

When i switch the power switch on the PS the mb will display a green light (saying its got power), when I press the button on the chassi all fans starts spinning and seems to be working. But no output from the screen, no sucessfull POST beep and the HDD is not spinning.

I have tried to run the computer without the IDE connected to the HDD, no luck but the HDD seems to be rotating.

In the HDD I have tried to switch the jumpers, at first I though it was running in slave mode, but after looking it was placed on the first jumper meaning its running master. But there is another jumper connected, it is the last one on the top, the one on the bottom isn´t connected.

If you have any idea why it isn´t working please post it =D.
And would also like to know what the last jumper does.

Also could someone tell me if you can boot without an HDD =D?

Thanks

More about : computer booting

a b B Homebuilt system
October 2, 2010 8:22:56 AM

I think it most likely that it is suffering a dead PSU or a dead motherboard. Have them tested.
October 2, 2010 8:27:19 AM

Wamphryi said:
I think it most likely that it is suffering a dead PSU or a dead motherboard. Have them tested.

I don´t think its a dead PSU though, when I only connect the molex power connector the HDD works. Though when I connect the IDE cable it dosen´t.
You could be right about the MB though.

Thanks for the info
Related resources
a b B Homebuilt system
October 2, 2010 4:55:11 PM

You can try to boot the system using a Windows setup disk, you may have to get into BIOS to change the boot order. Odds are good this won't work either.

By far the most likely cause is a failed psu. When they fail, they MOST OFTEN don't go completely dead. They just become incapable of providing the real power needed, or worse provide it erratically.

If you have another psu you can swap in, that would be a good start. If you don't have one, odds are good buying one will solve the problem. If the psu turns out not to be the problem, you'll have a useful tool for future debugging, or to use in your next build. So buy one with thatthought in mind, good quality, enough useful power, like this 550W Corsair for $60:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139004

It happens to be on sale, at around the price you'd have to pay for a smaller, known high-quality psu.
a c 122 B Homebuilt system
October 3, 2010 8:22:36 AM

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 beep 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.

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.

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.
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.
!