Fried Motherboard??


M

Mark

I am pretty sure I have a fried motherboard but I wanted to gather
other's thoughts. I was using my computer and everything just turned
off (computer only, tv, lamps, etc was still turned on) There was a
burning smell coming from the computer but I saw no smoke. The power
button on the machine did nothing so I thought the power supply was
burned out. I think the smell was coming from the PSU since I sniffed
it and it smelled burnt.

I had a spare PSU so I put that in the machine. Everything seemed to
power up (harddrive, cd rom, fans, etc) but no image to the monitor and
no POST beeps. I swapped out the video card and I noticed the
samething (powers up, but no POST or image). I took out the video card
and the RAM to see if could generate some post beeps. Everything
powered up again, (fans, cddrive, etc) but no POST beeps. I put the
video card and RAM back. I powered it up a few times and after one of
the times, there were a couple of very slight popping or cracking
sounds and then, again, more of a burning smell. The computer will no
longer power up at all now.

I have already order a new PSU, MOBO, RAM, and CPU since it is over
three years old. Just wondering what others thoughts are..dead mobo or
two dead PSU.
 
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M

Mark

I saw this posted so it made me think it that maybe it was the mobo all
along...

However, consider a power supply- it's rear fan expells air
from other parts of the system. If the case were closed and
then turned on, any burning smell would be air sucked into
the power supply (if not a rear case exhaust fan) and blown
out the rear of the power supply. For this reason it could
be possible that the power supply didn't burn, only appeared
to as the smell came out of through normal exhaust flow
movement.
 
P

Paul

"Mark" said:
I saw this posted so it made me think it that maybe it was the mobo all
along...

However, consider a power supply- it's rear fan expells air
from other parts of the system. If the case were closed and
then turned on, any burning smell would be air sucked into
the power supply (if not a rear case exhaust fan) and blown
out the rear of the power supply. For this reason it could
be possible that the power supply didn't burn, only appeared
to as the smell came out of through normal exhaust flow
movement.

Check the capacitors around the processor. You didn't say what
brand and model of motherboard, but there were quite a few
fatalities due to bad caps. The capacitors are cylinders with
a plastic sleeve on the outside. If the top is bulging, or
if you see a brown stain around the base, where some brown
fluid dried on, then your caps are bad. In extreme cases,
the switching MOSFETs can be ruined by trying to drive
the failing caps. So you may see one of the three legged
devices burned as well. "Homey" at motherboardrepair.com
can fix caps, if that is all that is damaged. But depending
on whether there is a warranty to fall back on, the
manufacturer may cover this as well.

In one case, it was so bad, that there was a class action
lawsuit.

http://www.abitsettlement.com/

The fastest solution is to pick up another motherboard.

Paul
 
K

kony

I am pretty sure I have a fried motherboard but I wanted to gather
other's thoughts. I was using my computer and everything just turned
off (computer only, tv, lamps, etc was still turned on) There was a
burning smell coming from the computer but I saw no smoke. The power
button on the machine did nothing so I thought the power supply was
burned out. I think the smell was coming from the PSU since I sniffed
it and it smelled burnt.

What make, model, wattage PSU? What's the rest of the
system like, a concise list of major components?


I had a spare PSU so I put that in the machine.

Know good quality and adequate for the system?... or
generic?
Everything seemed to
power up (harddrive, cd rom, fans, etc) but no image to the monitor and
no POST beeps.

Try clearing CMOS.
Check the battery- if the battery had been low and you then
disconnect power, for the first time in awhile it may need
the battery but it has now drained.
I swapped out the video card and I noticed the
samething (powers up, but no POST or image). I took out the video card
and the RAM to see if could generate some post beeps. Everything
powered up again, (fans, cddrive, etc) but no POST beeps. I put the
video card and RAM back. I powered it up a few times and after one of
the times, there were a couple of very slight popping or cracking
sounds and then, again, more of a burning smell. The computer will no
longer power up at all now.

Unplug everything except bare essentials- Motherboard, CPU,
heatsink/fan, your least-power-hungry video card (ideally a
really old PCI card), 1 memory module. Disconnect drives,
keyboard/mouse, even the front case wiring. Short the
motherboard's Pwr-On pin to ground with a metallic object.
Have the side off and listen and smell for anything
suspicious, while taking voltage readings if you have a
multimeter handy. Be sure to clear CMOS after disconnecting
all the parts- not just from the PSU but their data cables
from the motherboard as well.

By isolating everything as much as posssible (though you
could swap in different CPU or memory if you had them), if
it still doesn't work then it seems the motherboard is all
that's left (assuming the PSU was adequate, the 2nd PSU
since the first one may have failed, it's failure possibly
even damaging something else.
 
M

MJP

I am pretty sure I have a fried motherboard but I wanted to gather
other's thoughts. I was using my computer and everything just turned
off (computer only, tv, lamps, etc was still turned on) There was a
burning smell coming from the computer but I saw no smoke. The power
button on the machine did nothing so I thought the power supply was
burned out. I think the smell was coming from the PSU since I sniffed
it and it smelled burnt.

I had a spare PSU so I put that in the machine. Everything seemed to
power up (harddrive, cd rom, fans, etc) but no image to the monitor and
no POST beeps. I swapped out the video card and I noticed the
samething (powers up, but no POST or image). I took out the video card
and the RAM to see if could generate some post beeps. Everything
powered up again, (fans, cddrive, etc) but no POST beeps. I put the
video card and RAM back. I powered it up a few times and after one of
the times, there were a couple of very slight popping or cracking
sounds and then, again, more of a burning smell. The computer will no
longer power up at all now.

I have already order a new PSU, MOBO, RAM, and CPU since it is over
three years old. Just wondering what others thoughts are..dead mobo or
two dead PSU.


Have you tried to test the PSU's on their own?

Look here for details of how to do it and a diagram
http://www.duxcw.com/faq/ps/ps4.htm

MJP
 
M

Mark

Thanks for the tips everyone. I do realize I could have done more
troubleshooting but I figured since the system is over three old now,
it wouldn't hurt to upgrade it anyways. And it's definately possibly
the second power supply may of had issues because it was salvaged from
a machine that didn't work before. I just tried it to see if it would
work at all.

The original parts I have are the following.

Codegen 350 Watt PSU.
MSI 845E Max-L Mobo
Pentium 4 2.4 - 478 Chip

The second PSU is an Antec 300W.

I have added several devices through out the years such as ipods,
camera, usb mouse/keyboards, external HD. Not sure if those would
consume to much power for the PSU.
 
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K

kony

Thanks for the tips everyone. I do realize I could have done more
troubleshooting but I figured since the system is over three old now,
it wouldn't hurt to upgrade it anyways. And it's definately possibly
the second power supply may of had issues because it was salvaged from
a machine that didn't work before. I just tried it to see if it would
work at all.

The original parts I have are the following.

Codegen 350 Watt PSU.
MSI 845E Max-L Mobo
Pentium 4 2.4 - 478 Chip

The second PSU is an Antec 300W.

I have added several devices through out the years such as ipods,
camera, usb mouse/keyboards, external HD. Not sure if those would
consume to much power for the PSU.


Test both psu. Leave the codegen unpluged fo a few minutes,
open and inspect it. Not all damage would be visible, but
any visible damage is obviously a problem. What did the
smoke smell like? Caps may be like popcorn (somewhat), but
a fet, resistor or similar epoxy cased part smells quite
different. Given the sound and smell, there is likely a
visible damage but sometimes it's hard to see certain parts,
especially in a psu.

The alternative might be trying to get hold of another,
known good/quality/working/etc, psu.
 
A

Andy

If you dont want to grab another PSU you may try this small device
thats available at some Computer Supply stores that will allow you to
check out the Power Supplys (ATX). I think I picked it up for 12
bucks..will tell you if your supply is hosed or not and is made by
Antec.

Andy
 
K

kony

If you dont want to grab another PSU you may try this small device
thats available at some Computer Supply stores that will allow you to
check out the Power Supplys (ATX). I think I picked it up for 12
bucks..will tell you if your supply is hosed or not and is made by
Antec.

Unfortunately such devices have a limited usefulness. They
can tell you if the PSU is dead, but not that it's working
properly.
 
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L

larry moe 'n curly

Andy said:
If you dont want to grab another PSU you may try this small device
thats available at some Computer Supply stores that will allow you to
check out the Power Supplys (ATX). I think I picked it up for 12
bucks..will tell you if your supply is hosed or not and is made by
Antec.

PSU testers only tell if a voltage rail is completely dead or not, and
the one I borrowed said that everything was fine even when the +12V
rail was so low that the HD wouldn't even spin.

Spend the $12 on a cheap digital multimeter, a pair of power load
resistors, and paperclip, and you'll have a much better PSU tester that
isn't much harder to use but that can also test other stuff, like the
battery, CPU core voltage, cables, and switches.
 

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