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Computer not starting up

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  • Homebuilt
  • Computer
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Last response: in Systems
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July 26, 2010 2:02:13 PM

I'm not sure if this is in the right section or not but;

My computer isn't starting up. Everything is plugged in right and the case fans, PSU fan, GPU and heat sink fans are all working. Everything is normal for the first second or so when i boot up, but after, my HD 5830's fan becomes extremely loud. I am pretty sure my Power supply and motherboard are working because the lights on the motherboard are lit and the fans are all working. Is it because my Antec 650W PSU can't support my HD 5830 or is it because there is something wrong with my HD 5830?

In case you were wondering, it has been working perfectly fine for around 3 weeks, until yesterday.

Thanks.

More about : computer starting

a b B Homebuilt system
July 26, 2010 2:08:29 PM

If you suspect your 5830 see if you can get hold of a graphics card known to work fine and swap it out to test it. Are you getting a picture on the screen when you boot?
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a c 122 B Homebuilt system
July 26, 2010 2:21:25 PM

leapfrog01 said:
I am pretty sure my Power supply and motherboard are working because the lights on the motherboard are lit and the fans are all working.

That means very little. Working fans mean that the PSU is able to produce some small amount of 12 volt power. Motherboard LED's mean little more than the PSU is receiving power from the wall and the PSU is physically turned on.

leapfrog01 said:
Is it because my Antec 650W PSU can't support my HD 5830

Your Antec 650 can easily power a 5870 if everything is working properly.

If your video card wasn't working, you would get a BIOS beep pattern of a long and 3 short beeps - assuming that you do have a system speaker installed. You do, right? If not, you really need one for troubleshooting.

Worked through the checklist and troubleshooting thread that banthacis posted:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it.

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

The breadboarding thread has a paragraph about how to build and test a PC in stages.

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.

At this point, you can sort of check the PSU. Try to borrow a known good PSU. 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 PSU looks like it 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.
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