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No POST on while booting cant find exact problem

Last response: in Motherboards
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June 1, 2011 9:44:43 PM

Hi

Somebody help in below case

I have Intel D945GCNL Board. i have changed new cabinet till then it was not working. while booting there is no POST, i have removed all cards( Graphics card,Sound card,) removed HDD,Still there is no post. I have checked SMPS it is working fine with another PC, Before changing the cabinet everything was working fine. While switching on main power led is on in motherboard but processor fan itself is not spinning. Help me to troubleshoot this issue.

Thanks in Advance
a b V Motherboard
June 2, 2011 3:40:15 AM

Check for any shorts under the motherboard.
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a b V Motherboard
June 2, 2011 4:15:37 AM

Let's try a few things to see if we can't isolate out the problem:

#1: Clear CMOS -- your motherboard manual will tell you how to clear your CMOS.

#2: If clearing CMOS doesn't allow booting, try pulling out all the memory except for one stick. If that doesn't work -- swap it out for another of the sticks you have.

Please report back with what you find! Good luck!
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June 2, 2011 7:42:26 PM

PreferLinux said:
Check for any shorts under the motherboard.


Thanks for reply

How to check the short under the motherboard?


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June 2, 2011 7:52:44 PM

fullofzen said:
Let's try a few things to see if we can't isolate out the problem:

#1: Clear CMOS -- your motherboard manual will tell you how to clear your CMOS.

#2: If clearing CMOS doesn't allow booting, try pulling out all the memory except for one stick. If that doesn't work -- swap it out for another of the sticks you have.

Please report back with what you find! Good luck!


Hi

Thanks for reply

1) I checked clearing CMOS its no use

2) I have two memory module, checked with one memory and checked by swaping another one still no post.

3) If I switch on SMPS power led is getting on in motherboard, while switching on power button even processor fan is not spinning. kindly suggest

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a b V Motherboard
June 2, 2011 9:00:45 PM

nandha_99 said:
Thanks for reply

How to check the short under the motherboard?

Take the motherboard out, and set it up (with CPU & fan, RAM, graphics card and HDD) on something like a book or cardboard box (but beware, the solder on the bottom can be sharp, so it could do damage).
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Best solution

a c 156 V Motherboard
June 2, 2011 9:18:18 PM

nandha_99 said:

How to check the short under the motherboard?


PreferLinux said:
Take the motherboard out, and set it up (with CPU & fan, RAM, graphics card and HDD) on something like a book or cardboard box (but beware, the solder on the bottom can be sharp, so it could do damage).


It's called breadboarding.

Work systematically 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.
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.
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 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.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

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.
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a b V Motherboard
June 2, 2011 9:30:09 PM

nandha_99 said:
Hi

Thanks for reply

1) I checked clearing CMOS its no use

2) I have two memory module, checked with one memory and checked by swaping another one still no post.

3) If I switch on SMPS power led is getting on in motherboard, while switching on power button even processor fan is not spinning. kindly suggest


Wow - I'm really bummed that neither of those worked. Clearing CMOS almost always does the job.

Whatever you do, please report back on the ultimate resolution. It's rare to have a problem so intractable that doing the memory swap and the cmos-reset drill won't get it to boot...
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June 13, 2011 8:05:43 PM

Best answer selected by nandha_99.
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