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Computer doesn't reach POST. Bad mobo?

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  • Homebuilt
  • Computer
  • Systems
Last response: in Systems
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December 27, 2011 8:38:32 PM

Hello,

This may not be the correct section of the forum for this, and I apologize if it is not, but it seemed to be the best place to put it.

My computer recently shut down in the middle of a long gaming session and refused to turn back on. After some basic tests I decided it was the psu and received an rma replacement.

Well, it wasn't the psu. I still have the same problem I did before I got the replacement, and the replacement worked fine in another computer.

The problem is I don't reach POST at all. I get a brief surge of power to the fans when I hit the power switch, enough to move them a millimeter or two, and then nothing.

My biggest concern at this point is that it's the mobo or cpu. How do I tell what the problem is when I can't even get to POST?

Here is a list of my current hardware:

AMD Athlon II X3 440 Rana 3.0GHz
PowerColor AX3450 256MD2-H Radeon HD 3450 256MB 64-bit DDR2
MSI 770-G45 AM3 AMD 770 ATX AMD Motherboard
Kingston 2GB 240-Pin DDR3
OCZ ModXStream Pro 600W
Seagate Barracuda 7200 RPM 500 GB

Thanks in advance for your help.

More about : computer reach post bad mobo

a b B Homebuilt system
December 27, 2011 8:50:18 PM

A typical video about building your own system: http://www.youtube.com/watch?v=9TY6jy9isAk I use it for a checklist. All your parts look good, and your video card isn't high end. Other tips: try a matching pair of ram if your old ram has been tried in each ram slot. Could be a bad stick. Also try posting with the hardrive unplugged. Good luck.
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December 27, 2011 8:59:53 PM

o1die said:
A typical video about building your own system: http://www.youtube.com/watch?v=9TY6jy9isAk I use it for a checklist. All your parts look good, and your video card isn't high end. Other tips: try a matching pair of ram if your old ram has been tried in each ram slot. Could be a bad stick. Also try posting with the hardrive unplugged. Good luck.


Yeah, I used that video as a checklist when I put it together about a year ago. It worked fine up until just recently. When it first happened I tried removing parts one at a time, plugging them in in different combinations, etc. No matter what I did I couldn't reach POST. I'm going to try unplugging the hard drive again, though. It's worth a shot at it being such an easy fix. Unfortunately I have no spare ddr3 laying around.
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a c 78 B Homebuilt system
December 27, 2011 9:06:13 PM

Here is how I figure it...

When a computer turns off gracefully and never comes back on, it is most likely a power problem.

You RMAd your PSU and got one back that you tried in another computer and it works. We have to assume it is a known good PSU at this point.

It is extremely rare that RAM or CPUs go bad when they have worked in the past in my experience. Usually, again in my experience, they either work right the first time or they never work right.

I am going to assume they are both still good.

Hard drives often fail, but a hard drive failure probably wouldn't keep you from POSTing.

That about narrows it down to the motherboard.

Anyway, that is my guess as to the problem child.
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December 27, 2011 9:13:28 PM

Raiddinn said:
Here is how I figure it...

When a computer turns off gracefully and never comes back on, it is most likely a power problem.

You RMAd your PSU and got one back that you tried in another computer and it works. We have to assume it is a known good PSU at this point.

It is extremely rare that RAM or CPUs go bad when they have worked in the past in my experience. Usually, again in my experience, they either work right the first time or they never work right.

I am going to assume they are both still good.

Hard drives often fail, but a hard drive failure probably wouldn't keep you from POSTing.

That about narrows it down to the motherboard.

Anyway, that is my guess as to the problem child.



You're right. Removing the HD did nothing.

I guess my only option at this point is to test the CPU in another PC and, if it works, replace the motherboard. Thanks for all your help, folks. That's why I posted here.
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December 27, 2011 9:14:42 PM

Just incase you haven't seen this link:

http://www.tomshardware.com/forum/261145-31-perform-ste...

Not likely to be any of the 'building stage' steps given that it was working... but some good links at the bottom.

Was anything overclocked in your system? Tried flashing the BIOS?

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December 27, 2011 9:30:26 PM

Formata said:
Just incase you haven't seen this link:

http://www.tomshardware.com/forum/261145-31-perform-ste...

Not likely to be any of the 'building stage' steps given that it was working... but some good links at the bottom.

Was anything overclocked in your system? Tried flashing the BIOS?


I went through those steps and thought I saw something that I'd forgotten to do, but no such luck.

Nothing was overclocked, I don't do much with that for the simple reason of trying to avoid these kinds of problems in the first place.

I haven't tried flashing the bios if only for the simple fact that I can't get enough power to do so.

I'm fairly certain it's the mobo. I plan on trying the CPU in another board as soon as I get the chance and, if that is the problem, biting the bullet and getting a replacement.
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December 27, 2011 9:47:45 PM

oddonein said:


I haven't tried flashing the bios if only for the simple fact that I can't get enough power to do so.



Have you tried doing it this way (removing the battery)?

http://www.spotht.com/2010/02/reset-bios-clear-cmos.htm...

Suppose you've tried getting it to post with basically everything taken off the mobo HDDs, Mem, additional Sata or IDE drives & connectors, any fans etc?
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December 27, 2011 9:56:11 PM

Formata said:
Have you tried doing it this way (removing the battery)?

http://www.spotht.com/2010/02/reset-bios-clear-cmos.htm...

Suppose you've tried getting it to post with basically everything taken off the mobo HDDs, Mem, additional Sata or IDE drives & connectors, any fans etc?


I actually hadn't tried taking the battery out. This is sort of embarrassing, but I can't seem to get the battery to come out.

I'm going to try disconnecting everything again. I tried it the first time around, but not with the new psu.
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December 27, 2011 10:18:02 PM

Removed the CMOS battery. Nothing.

Removed everything. Nothing.

I'm going to find another AMD board and test the CPU. If that doesn't work I guess it pretty much narrows it down to the mobo.
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December 27, 2011 11:26:16 PM

Best answer selected by oddonein.
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December 27, 2011 11:52:38 PM

Make sure you test each thing individually.

Not posting could be:
1) Bad CPU
2) Bad MB
3) Bad RAM
4) Bad Video Card
5) Some other bad thing.

To make sure it's not #5 disconnect EVERYTHING (including USB connections) except RAM, Video and power switch, MB and CPU power.

If it still doesn't post your next easiest things to check are Video card and RAM.

If you don't have a spare Video card and your MB will run with a single stick of RAM try booting it with a single stick. If it still won't post switch sticks and try again.

If it still won't post borrow a video card and the try it again, still with a single stick of RAM (if possible). If it doesn't work, switch RAM sticks and try again.

If it still doesn't post then it's most likely the MB or CPU.

Check the MB with a flashlight, inspect the capacitors in particular closely for bulges or leaking fluid or dark spots on the MB from a fried component. The damage could be VERY small and still keep your computer from POSTing so look very closely.

If you don't overclock then the CPU is probably NOT the problem. I've been building my own computers and building them for friends and family for 20 years and I don't recall the CPU being a problem more than once or twice in all that time.

If it still won't post after all other attempts, it's most likely the MB.

Hope this helps.
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