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Either Dead CPU or Defecitve MoBo

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Anonymous
a b V Motherboard
April 14, 2011 8:08:28 AM

So I just went out and purchased a Gigabyte GA-G41-Combo motherboard for a build made primarily of my old parts. I went to install my old processor (a Q8200) and nothing would post on the screen. Odd. Also, No beeps. Really odd. I take out the memory and re-seat it just for good measure (I was using the DDR2 channel, with some spare kingston DDR2 I had laying around. It is known to work in other computers.) Still nothing posting on screen. No beeps. I try some Patriot DDR3 1333 I had in my other computer. Still no signs of life. I try a different PSU (tearing apart my other computer in the process. I used a Corsair tx650w as the second PSU). Nothing again.

Now here is where I tried something I had never done before. I unplugged the 4 pin CPU power on the left side of the motherboard and the motherboard turned on, fans spinning (BTW it did that every time up to this as well) but still no beeps, no display. I figured OK either I had a bad mobo or a dead CPU. It isn't surprising the CPU could be dead, as the board it was in previously died as well. But more antics ensued. For laughs I unplugged the 4 extra pins that go with the main MB power making it a 20 pin connection. Again, fans spin up, lights come on. Nothing on screen. No beeps, no display. I get annoyed and return the MB to it's normal 24-pin configuration (I put the 4 extra pins back into the motherboard). and I proceed to tear down the system. I removed the CPU and just to see what would happen, I turn the system on.

Same thing. Lights come on, fans spin up but no beeps, and obviously no display.

What gives? Am I dealing with a defective motherboard or what?
a c 1097 V Motherboard
April 14, 2011 8:56:49 AM

CPU? Motherboard? Most of the time it would be a bad motherboard but here maybe CPU. What was the symptoms of the old board failing?
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a c 156 V Motherboard
April 14, 2011 1:15:35 PM

Or PSU.

System will not even try to POST without CPU or CPU power.

It is time to start testing systematically.

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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Anonymous
a b V Motherboard
April 14, 2011 8:15:30 PM

Did either of you READ my post? I tried 2 separate PSU's. The first just a generic one, the second a Corsair tx650w that I know is in perfect working condition. So telling to me test a PSU is REALLY not going to help when I've already gone that route.

Second, the motherboard I bought (and was listed as compatible) was a Gigabyte GA-G41-Combo. Previously this CPU was housed in a Intel DP45SG motherboard, but that fried some how (no voltage going through it, no POST, no fans, no lights, no nothing.)

I've already started the process of RMA'ing the Q8200, as it's the prime suspect. I will be getting a CPU to test the motherboard later today (a Celeron D 430J) to see it if is a motherboard issue or not.

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Anonymous
a b V Motherboard
April 15, 2011 5:52:22 AM

It was CPU. I put in a older Celeron and it fired right up. Thanks... oh wait, no one helped!

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Anonymous
a b V Motherboard
April 15, 2011 5:52:24 AM

It was CPU. I put in a older Celeron and it fired right up. Thanks... oh wait, no one helped!

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Best solution

a c 1097 V Motherboard
April 15, 2011 6:22:05 AM

Quote:
It was CPU. I put in a older Celeron and it fired right up. Thanks... oh wait, no one helped!

Oh wait! My first response "CPU? Motherboard? Most of the time it would be a bad motherboard but here maybe CPU. What was the symptoms of the old board failing?"
See the question mark?
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April 15, 2011 4:42:55 PM

Quote:
It was CPU. I put in a older Celeron and it fired right up. Thanks... oh wait, no one helped!


Try to have some grace, people here are just trying to help you.
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Anonymous
a b V Motherboard
April 17, 2011 8:03:18 PM

ethel said:
Try to have some grace, people here are just trying to help you.

If you have nothing useful to say, remain silent.
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Anonymous
a b V Motherboard
April 17, 2011 8:03:51 PM

Best answer selected by greeneman510.
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April 17, 2011 11:08:31 PM

Quote:
If you have nothing useful to say, remain silent.


I think my advice was useful - whether you are wise enough to take it is up to you.
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!