Which part of this PC is dead?

Wedge · Post by **Wedge** » Sat Apr 05, 2008 5:31 pm

I am diagnosing a friends PC issue. So far, the only thing i can determine is that there is no video signal. It is an e-Machine with onboard video:
nVidia GeForce 6100 GPU

I placed a PCI (not PCIe) video card in an available slot, still no video.

So now I am inclined to think that the motherboard has gone bad (and not just the video chipset that is build into it).

I guess the question I have is, if I am looking at a bad component on the motherboard, rather than the motherboard itself, say the CPU, I should still get a video signal in order to see if the system is POSTing, correct?

xan_user · Post by **xan_user** » Sat Apr 05, 2008 6:11 pm

Even with no cpu in the board you should still be able to see post screen with either on board or pci video.

Any beeps?

Loose or bad ram can cause no post no beep.

Bad PSU can also cause no boot no video in rare cases.

...of course there is bad video cable or monitor to consider...or incompatible screen resolution and or frequency.

frostedflakes · Post by **frostedflakes** » Sat Apr 05, 2008 7:12 pm

You sure about that? I'm pretty sure with a bad or no CPU the computer won't do anything. Same goes for RAM.

When you start up the computer and let it run for a little bit, does the HDD indicator light show activity? If this is the case that would mean it's loading up the OS and that the problem is simply video output, which means bad motherboard. If you get power, but it doesn't appear that the computer is doing anything, things get a bit tougher to troubleshoot. Could be either mobo, CPU, or RAM, and I can't really think of any way to check further short of swapping components. RAM shouldn't be too tough to rule out if he has more than one stick in there, just try booting with each stick separately and if you still get nothing, it's probably not RAM (possible, but unlikely, that both sticks failed at the same time).

VanWaGuy · Post by **VanWaGuy** » Sat Apr 05, 2008 7:26 pm

I have fixed a few bad emachines for friends. Each of them had a bad power supply that died with a voltage too high, and damaged the motherboard too. Either 2 or 3 of them still had a good CPU and memory. Luckily, I have several machines and was able to swap parts around to isolate the bad part(s).

There is one power supply that they used that I saw web sites trying to organize a class action suit because so many failed. I think it was a very small Bestec (or something close to that) supply.

With a good supply, some LEDs would light up, and fans spin, but no video.

Wedge · Post by **Wedge** » Sat Apr 05, 2008 7:51 pm

The PSU is indeed Bestec and i had thought about that, but it is providing power. Whether it is an adequate amount or not, I am unsure. I could certainly use a tried and trusted PSU just to be sure that it is not a power issue.

I have already swapped in some RAM from one of my PCs. It's definitely not a RAM issue and there are no beeps.

I will report back soon. Going to try a different PSU.

Wedge · Post by **Wedge** » Sat Apr 05, 2008 8:09 pm

New PSU was a no-go. The damage, regardless what caused it, is done.

Interesting note though: The Bestec PSU is only 20-pin. Do not all PCIe boards need 24-pin?

xan_user · Post by **xan_user** » Sat Apr 05, 2008 8:16 pm

So far the boards i've tried bare(10 maybe), if they have on board video, will at least post to bios w/o eiterh cpu or ram.

After thinking about this e-machine...
It could be a fried south bridge, seen more of those popping up as boards get older and dustier, and thumbdrives become more prevalent.

Wedge · Post by **Wedge** » Sat Apr 05, 2008 8:21 pm

xan_user wrote:So far the boards i've tried bare(10 maybe), if they have on board video, will at least post to bios w/o eiterh cpu or ram.

Good to know. I assumed this to be the case, but I have never tested it to see.

Would this Foxconn board be a suitable replacement?

VanWaGuy · Post by **VanWaGuy** » Sat Apr 05, 2008 11:40 pm

xan, That does not make sense that a board can post without the CPU.

The BIOS is code and data in a FLASH ROM. It takes a CPU to read those instructions and do anything.

A board can start to run with no RAM if a CPU is there. I have had them run enough to beep when there was no RAM.

VanWaGuy · Post by **VanWaGuy** » Sat Apr 05, 2008 11:51 pm

Wedge,

Try to verify that the CPU and RAM are good before purchasing the board. If they are all bad, go with something newer.

The board you reference uses the same memory type, so that is good, and it is a micro-ATX, so should fit. I did not see what type of socket is on the old machine, so verify that, and the new board has 2 IDE ports, so should handle the old optical and hard drives.

If the CPU or RAM is bad, you might consider something like one of the low end Frys specials, they often have like an ECS mobo and Athlon X2 for $60 or $70. Catch some Ram on sale too, and makes for a nice upgrade.

Wedge · Post by **Wedge** » Sun Apr 06, 2008 4:43 am

VanWaGuy wrote: The BIOS is code and data in a FLASH ROM. It takes a CPU to read those instructions and do anything.
[snip...]
Try to verify that the CPU and RAM are good before purchasing the board. If they are all bad, go with something newer.

Glad you mentioned that about the CPU. At this point I am unsure if I am looking at a bad board or processor (or both).

VanWaGuy wrote: If the CPU or RAM is bad, you might consider something like one of the low end Frys specials, they often have like an ECS mobo and Athlon X2 for $60 or $70. Catch some Ram on sale too, and makes for a nice upgrade.

Yes I noticed at Fryes there was an 4200x2 with an ECS board on the cheap last night.

I do not have a spare socket 754 CPU for testing this board. Is there another way?

Plissken · Post by **Plissken** » Sun Apr 06, 2008 11:50 am

It's pretty hard to fry a CPU unless you overheat or overvolt it. Also tough to kill RAM. Chances are it's just the mobo that is dead.

That said, unless money is really tight, I would not buy a socket 754 mobo to resuscitate a dying e-machine. I would upgrade all 3 (and the PSU) and give the E-dog some new life! Or just start over, because something else on that machine (PSU, hard drive) is probably going to die soon as well.

Wedge · Post by **Wedge** » Mon Apr 07, 2008 2:03 pm

Wedge wrote:New PSU was a no-go. The damage, regardless what caused it, is done.

Interesting note though: The Bestec PSU is only 20-pin. Do not all PCIe boards need 24-pin?

Bump for this question: For a PCIe motherboard, do I need a PSU that has the 24-pin connector? The Bestec PSU did NOT have but a 20-pin.

jaganath · Post by **jaganath** » Mon Apr 07, 2008 2:59 pm

For a PCIe motherboard, do I need a PSU that has the 24-pin connector?

AFAIAA, no. the extra 4 pins do send juice to the PCIe slot but irrelevant here as onboard graphics used.

xan_user · Post by **xan_user** » Mon Apr 07, 2008 3:10 pm

VanWaGuy wrote:xan, That does not make sense that a board can post without the CPU.

The BIOS is code and data in a FLASH ROM. It takes a CPU to read those instructions and do anything.

A board can start to run with no RAM if a CPU is there. I have had them run enough to beep when there was no RAM.

Your right !
poor choice of words..
I should have said "displayed an error message during the failed post".
"error no cpu installed!" -in my brain.

__

andyb · Post by **andyb** » Mon Apr 07, 2008 3:23 pm

Hiya Wedge, buy one of these.

http://www.ebuyer.com/product/99889

Your PSU is probably dead, Bestec make the worst PSU's I have ever seen, I call them Worstec its a more accurate name.

That doesnt mean to say that your mobo is OK, Worstec PSU's often fry the motherboards when they go pop, I would say 30% of the time.

The easiest way to check is to disconnect everything from the mobo except the power switch and a PS/2 keyboard, hook up a working PSU but dont power plug in the power until you have wiped the CMOS, turn it on and watch the LED's on the keyboard, if they dont all flash at the same time within 10 seconds or so your mobo is history.

The chances of your CPU and RAM being wiped out as well are very slim (1% or less), but evaluate their worth before buying stuff.

Your right !
poor choice of words..
I should have said "displayed an error message during the failed post".
"error no cpu installed!" -in my brain.

Thats more like it, but I have never seen that message, not that I turn on many PC's with their CPU's missing or RAM, Mobo's, or PSU's - although I often turn PC's on without Zip drives being plugged in

Andy

yefi · Post by **yefi** » Tue Apr 08, 2008 9:57 am

VanWaGuy wrote:The BIOS is code and data in a FLASH ROM. It takes a CPU to read those instructions and do anything.

I once RMA'ed a mobo I'd tested with no CPU. I then had to pay out my nose to have it shipped back after I'd realised my dumb mistake.