PSU's pin looked burnt

Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



Which connector of the psu looks burnt?
There are a few things you can try if the connector that's burnt isn't
connecting directly to the motherboard.
If the connector that's burnt is the 4 pin connector with 2 yellow and 2
black wires then chances are that the motherboard is fried.

--
Mark Mckee
CompTIA A+ Certified www.comptie.org

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



Which connector of the psu looks burnt?
There are a few things you can try if the connector that's burnt isn't
connecting directly to the motherboard.
If the connector that's burnt is the 4 pin connector with 2 yellow and 2
black wires then chances are that the motherboard is fried.

--
Mark Mckee
CompTIA A+ Certified www.comptie.org

There are 4 pin connectors that connect to
the motherboard, some video cards and also
hard drives and some cooling fans. Could you
be more specific as to which connector and the
color of the wires to the burnt pins.

--
JS
http://www.pagestart.com



"ML" wrote in message
...
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU
but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.

There are 4 pin connectors that connect to
the motherboard, some video cards and also
hard drives and some cooling fans. Could you
be more specific as to which connector and the
color of the wires to the burnt pins.

--
JS
http://www.pagestart.com



"ML" wrote in message
...
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU
but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



The square connector, with two yellow wires and two black wires, powers
the processor. The processor does not use the power directly. There is
the "Vcore switching power converter" which is located near the processor
socket, which converts the 12V from the two yellow wires, into 1.5V
or less for the processor.

(Picture of some of the components involved in Vcore power conversion.)

http://img365.imageshack.us/img365/6...yv266b1fj3.jpg

If the capacitors fail, the tops bulge and leak. That
is shown here. The tops of each cylinder should be flat.
The reason there are stamped lines in the top of the
cylinder, is for pressure release. In this case, the
pressure built up, until the stamped lines split.
Relieving the pressure before it becomes too great,
prevents accidents. Sometimes the leakage is brown or
orange in color. These are failed caps.

http://img395.imageshack.us/img395/5...ploded1hx9.jpg

If a cap fails, it can cause collateral damage. If bad enough,
it might even short the 12V feeding that circuit. That in
turn, would burn the pins on the 2x2 square connector.

The pins are rated at about 8 amps or so. To burn the
pins, you'd need to draw more than 16 amps at 12V (since
there are two pins on the yellow wires, and each takes up
to 8 amps). Connectors are rated according to power handling,
and 8 amps is about the limit for a Mini-Fit Jr connector of
that type and size. (The limit on the main connector is 6 amps,
due to so many hot pins being next to one another.) To burn
them, probably takes more current than that. (50% to 100%
more perhaps, to burn them nicely.)

So start by visually examining the components in Vcore. It
could be a leaking cylinder, a burned toroid, a burned three
tab MOSFET, and so on. Those could all be signs that the
motherboard needs repair or replacement.

Since your PC was previously working, it probably isn't a
mis-wired power supply. Since the system was working
at one time, that isn't likely to be the root cause of
the problem in this case. Some modular power supplies
(where the cable assemblies unplug), can have the wire
assembly plugged in, rotated 180 degrees. And that is
a possible cause of reversed power as well. It took the
modular power supply designers a few generations of
design, to "buy a clue" about the importance of keying.
Reversing the wires, can cause a lot of power to flow,
and will ruin the Vcore circuit.

If your system used an Intel D 805 overclocked to 4GHz,
that would be another reason for the pins to burn.
If that was your hardware configuration, you would have
mentioned that by now :-) Systems with that hardware and
level of overclock, draw more than 200W from Vcore.

Paul

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



The square connector, with two yellow wires and two black wires, powers
the processor. The processor does not use the power directly. There is
the "Vcore switching power converter" which is located near the processor
socket, which converts the 12V from the two yellow wires, into 1.5V
or less for the processor.

(Picture of some of the components involved in Vcore power conversion.)

http://img365.imageshack.us/img365/6...yv266b1fj3.jpg

If the capacitors fail, the tops bulge and leak. That
is shown here. The tops of each cylinder should be flat.
The reason there are stamped lines in the top of the
cylinder, is for pressure release. In this case, the
pressure built up, until the stamped lines split.
Relieving the pressure before it becomes too great,
prevents accidents. Sometimes the leakage is brown or
orange in color. These are failed caps.

http://img395.imageshack.us/img395/5...ploded1hx9.jpg

If a cap fails, it can cause collateral damage. If bad enough,
it might even short the 12V feeding that circuit. That in
turn, would burn the pins on the 2x2 square connector.

The pins are rated at about 8 amps or so. To burn the
pins, you'd need to draw more than 16 amps at 12V (since
there are two pins on the yellow wires, and each takes up
to 8 amps). Connectors are rated according to power handling,
and 8 amps is about the limit for a Mini-Fit Jr connector of
that type and size. (The limit on the main connector is 6 amps,
due to so many hot pins being next to one another.) To burn
them, probably takes more current than that. (50% to 100%
more perhaps, to burn them nicely.)

So start by visually examining the components in Vcore. It
could be a leaking cylinder, a burned toroid, a burned three
tab MOSFET, and so on. Those could all be signs that the
motherboard needs repair or replacement.

Since your PC was previously working, it probably isn't a
mis-wired power supply. Since the system was working
at one time, that isn't likely to be the root cause of
the problem in this case. Some modular power supplies
(where the cable assemblies unplug), can have the wire
assembly plugged in, rotated 180 degrees. And that is
a possible cause of reversed power as well. It took the
modular power supply designers a few generations of
design, to "buy a clue" about the importance of keying.
Reversing the wires, can cause a lot of power to flow,
and will ruin the Vcore circuit.

If your system used an Intel D 805 overclocked to 4GHz,
that would be another reason for the pins to burn.
If that was your hardware configuration, you would have
mentioned that by now :-) Systems with that hardware and
level of overclock, draw more than 200W from Vcore.

Paul

Hello

It's the 4-pins (that sits on one corner on the MOBO): 2 blacks and 2 yellows.
The 2 yellows pins, inside the plastic connector looked burnt.
Previous condition was that the PSU's fan and CPU's fan were spinning when
the main power was switch on but not yet press the switch on the casing.
At that time I was looking at the wrong place to solve that problem. I
didn't look at the PSU's connectors.

Thanks.

"Markmckee601" wrote:

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



Which connector of the psu looks burnt?
There are a few things you can try if the connector that's burnt isn't
connecting directly to the motherboard.
If the connector that's burnt is the 4 pin connector with 2 yellow and 2
black wires then chances are that the motherboard is fried.

--
Mark Mckee
CompTIA A+ Certified www.comptie

Hello

It's the 4-pins (that sits on one corner on the MOBO): 2 blacks and 2 yellows.
The 2 yellows pins, inside the plastic connector looked burnt.
Previous condition was that the PSU's fan and CPU's fan were spinning when
the main power was switch on but not yet press the switch on the casing.
At that time I was looking at the wrong place to solve that problem. I
didn't look at the PSU's connectors.

Thanks.

"Markmckee601" wrote:

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



Which connector of the psu looks burnt?
There are a few things you can try if the connector that's burnt isn't
connecting directly to the motherboard.
If the connector that's burnt is the 4 pin connector with 2 yellow and 2
black wires then chances are that the motherboard is fried.

--
Mark Mckee
CompTIA A+ Certified www.comptie

Good chance based on your description
that the mobo is fried and possibly the CPU.

Pull the motherboard and inspect it
(look for discoloration) carefully in the area near the CPU.

Also check to see if there is a burnt smell.

--
JS
http://www.pagestart.com



"ML" wrote in message
...
Hello

It's the 4-pins (that sits on one corner on the MOBO): 2 blacks and 2
yellows.
The 2 yellows pins, inside the plastic connector looked burnt.
Previous condition was that the PSU's fan and CPU's fan were spinning when
the main power was switch on but not yet press the switch on the casing.
At that time I was looking at the wrong place to solve that problem. I
didn't look at the PSU's connectors.

Thanks.

"Markmckee601" wrote:

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the
PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



Which connector of the psu looks burnt?
There are a few things you can try if the connector that's burnt isn't
connecting directly to the motherboard.
If the connector that's burnt is the 4 pin connector with 2 yellow and 2
black wires then chances are that the motherboard is fried.

--
Mark Mckee
CompTIA A+ Certified www.comptie

Good chance based on your description
that the mobo is fried and possibly the CPU.

Pull the motherboard and inspect it
(look for discoloration) carefully in the area near the CPU.

Also check to see if there is a burnt smell.

--
JS
http://www.pagestart.com



"ML" wrote in message
...
Hello

It's the 4-pins (that sits on one corner on the MOBO): 2 blacks and 2
yellows.
The 2 yellows pins, inside the plastic connector looked burnt.
Previous condition was that the PSU's fan and CPU's fan were spinning when
the main power was switch on but not yet press the switch on the casing.
At that time I was looking at the wrong place to solve that problem. I
didn't look at the PSU's connectors.

Thanks.

"Markmckee601" wrote:

ML wrote:
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the
PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



Which connector of the psu looks burnt?
There are a few things you can try if the connector that's burnt isn't
connecting directly to the motherboard.
If the connector that's burnt is the 4 pin connector with 2 yellow and 2
black wires then chances are that the motherboard is fried.

--
Mark Mckee
CompTIA A+ Certified www.comptie

"ML" wrote in message
...
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU
but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



This works best with a PS/2 keyboard, but sometimes it will work on USB
keyboards too.

Power down for a few secs... while holding down the delete key, turn the
power back on.

"ML" wrote in message
...
Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU
but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.



This works best with a PS/2 keyboard, but sometimes it will work on USB
keyboards too.

Power down for a few secs... while holding down the delete key, turn the
power back on.

On Thu, 18 Jun 2009 09:30:20 -0700, ML
wrote:

Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU but
still couldn't get the PC to start. The yellow LED on the MOBO is on when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.

You can ask in a pure hardware group somewhere. Your problem has
nothing to do with XP (please read the group title).

"Mr. Smith" wrote in message
...
On Thu, 18 Jun 2009 09:30:20 -0700, ML
wrote:

Hello

The PSU's 4-pins has 2 of the pins looked burnt. I have replaced the PSU
but
still couldn't get the PC to start. The yellow LED on the MOBO is on
when
power is switched on.
What are the chances that the MOBO is fried?
What else can I do?

Thank you.

You can ask in a pure hardware group somewhere. Your problem has
nothing to do with XP (please read the group title).

Ignore our resident mental retard.

Your question is welcome.