Asrock PE PRO-HT - help needed

  • Thread starter Thread starter Darek
  • Start date Start date
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Darek

Hello,
My friend got his MB toasted. I was able to identify, which part is
burnt, but i am unable to read the part number. I hope that there is
someone, who has such a mainboard and will be able to tell me, what part
am I looking for. I need to know the exact symbol to replace this element.

The mainboard image with the damaged element marked is here:
http://img528.imageshack.us/img528/2157/pc0400881zu.jpg

And here is the closer look:
http://img528.imageshack.us/img528/6697/pc0400925xf.jpg

Thanks in advance, I will appreciate any help :)
 
Darek said:
Hello,
My friend got his MB toasted. I was able to identify, which part is
burnt, but i am unable to read the part number. I hope that there is
someone, who has such a mainboard and will be able to tell me, what
part am I looking for. I need to know the exact symbol to replace this
element.

The mainboard image with the damaged element marked is here:
http://img528.imageshack.us/img528/2157/pc0400881zu.jpg

And here is the closer look:
http://img528.imageshack.us/img528/6697/pc0400925xf.jpg

Thanks in advance, I will appreciate any help :)
Click to expand...

You are on the proverbial fool's mission. There is 100% probability
that there is other hidden damage to the board. Time to move on,
remembering what caused this board failure so as not to make the same
mistake twice.

Q
 
Quaoar said:
You are on the proverbial fool's mission. There is 100% probability
that there is other hidden damage to the board. Time to move on,
remembering what caused this board failure so as not to make the same
mistake twice.

Q
Click to expand...

I know. I don't like Asrock either. I would rather like to play with it
"in the name of science". And of course - You are probably right, there
is a very high chance that something more has been damaged. But since
the MB is being replaced tomorrow - I can play with it for a while
before trashing it :)
 
I know. I don't like Asrock either. I would rather like to play with it
"in the name of science". And of course - You are probably right, there
is a very high chance that something more has been damaged. But since
the MB is being replaced tomorrow - I can play with it for a while
before trashing it :)
Click to expand...

If you are getting an exact replacement for the board tomorrow,
copy the numbers off the top of the chip, on the new board. Then post
them tomorrow and we'll tell you what it is, if possible. If there
is a logo printed on the chip, that helps too -- either sketch
the logo or describe it.

The best picture of the motherboard is on the Asrock site, but it
isn't good enough to get a part number. I don't see a logo, and
only two rows of numbers/letters. One row has four characters,
and that is likely the date code (WWYY) like 0305.

Paul
 
Paul said:
If you are getting an exact replacement for the board tomorrow,
copy the numbers off the top of the chip, on the new board. Then post
them tomorrow and we'll tell you what it is, if possible. If there
is a logo printed on the chip, that helps too -- either sketch
the logo or describe it.

The best picture of the motherboard is on the Asrock site, but it
isn't good enough to get a part number. I don't see a logo, and
only two rows of numbers/letters. One row has four characters,
and that is likely the date code (WWYY) like 0305.

Paul
Click to expand...

That's the problem. Like I already said - Asrock isn't my favorite
brand, so I will replace it with Asus, Abit, Gigabyte or so. This is the
reason why I am looking for someone, who has this mobo.

I was able to read from the damaged chip the last digit - it's 8. The
one earlier could be 5 (so this could be LM358, but I am not sure about
that). I will wait a little more, maybe someone could confirm this.
 
That's the problem. Like I already said - Asrock isn't my favorite
brand, so I will replace it with Asus, Abit, Gigabyte or so. This is the
reason why I am looking for someone, who has this mobo.

I was able to read from the damaged chip the last digit - it's 8. The
one earlier could be 5 (so this could be LM358, but I am not sure about
that). I will wait a little more, maybe someone could confirm this.
Click to expand...


I suspect it is an LM358, but I don't know it for certain.

Since that is the supply for the memory, you might want to
leave the memory out of the motherboard for testing
purposes, until you measure the voltage and confirm it in
the expected (~ 2.5-2.8V) range.
 
That's the problem. Like I already said - Asrock isn't my favorite
brand, so I will replace it with Asus, Abit, Gigabyte or so. This is the
reason why I am looking for someone, who has this mobo.

I was able to read from the damaged chip the last digit - it's 8. The
one earlier could be 5 (so this could be LM358, but I am not sure about
that). I will wait a little more, maybe someone could confirm this.
Click to expand...

I had a look at the LM358 datasheet (national.com), and while it
has a current limit on it, it has no thermal protection.

"Note 2: Short circuits from the output to V+ can cause excessive
heating and eventual destruction. When considering short cirucits
to ground, the maximum output current is approximately 40 mA
independent of the magnitude of V+. At values of supply voltage
in excess of +15V, continuous short-circuits can exceed the power
dissipation ratings and cause eventual destruction. Destructive
dissipation can result from simultaneous shorts on all amplifiers."

Did you plug in a DIMM backwards or something ?

In any case, if you ever find a clear enough picture of the board,
and the cause of the short circuit is removed from the board,
check with an ohmmeter on pin 1 or pin 7, to see if the
chip is still shorted to something like a power supply rail.
There could be some other component that is damaged as well,
as it is unlikely the opamp drives the load directly. Like a
failed MOSFET or something.

If you did reverse a DIMM, or partially install a DIMM (not fully
seated), there could be other damages you cannot see.

Paul
 
Paul said:
Did you plug in a DIMM backwards or something ?
Click to expand...
No :) I'm not that strong :) Besides this is not my mobo. But the owner
of this board could do anything to it, so this is the possible case.
In any case, if you ever find a clear enough picture of the board,
and the cause of the short circuit is removed from the board,
check with an ohmmeter on pin 1 or pin 7, to see if the
chip is still shorted to something like a power supply rail.
Click to expand...
Pin 1 seems to be shorted to +3.3V rail. I've checked all the pins
versus all power rails and 0V. I was expecting GND (4) connected to 0V
or -5V or -12V, and +V (8) connected to either +3.3/+5/+12V or to the
output of one of the mosfets on board. But they are not. And no other
pins are.
There could be some other component that is damaged as well,
as it is unlikely the opamp drives the load directly. Like a
failed MOSFET or something.
Click to expand...
Probably. For now I just tested mosfets around this chip if they are
shorted, but mosfets seem to be ok.
If you did reverse a DIMM, or partially install a DIMM (not fully
seated), there could be other damages you cannot see.

Paul
Click to expand...
I just tried to replace the chip with LM358. It didn't blow up, it's
cold. But the mobo still refuses to wake up (both on DDRs and SDRs). So
either this is not the correct chip, or - like You said - there is
something more damaged. Bios beeps with a memory error code.

Anyway - thanks for help. I'll leave the board alone for some time now,
maybe someone will identify this chip on his/her mainboard and write
it... If not, this mb isn't worth too much trouble :)
 
No :) I'm not that strong :) Besides this is not my mobo. But the owner
of this board could do anything to it, so this is the possible case.

Pin 1 seems to be shorted to +3.3V rail. I've checked all the pins
versus all power rails and 0V. I was expecting GND (4) connected to 0V
or -5V or -12V, and +V (8) connected to either +3.3/+5/+12V or to the
output of one of the mosfets on board. But they are not. And no other
pins are.

Probably. For now I just tested mosfets around this chip if they are
shorted, but mosfets seem to be ok.

I just tried to replace the chip with LM358. It didn't blow up, it's
cold. But the mobo still refuses to wake up (both on DDRs and SDRs). So
either this is not the correct chip, or - like You said - there is
something more damaged. Bios beeps with a memory error code.

Anyway - thanks for help. I'll leave the board alone for some time now,
maybe someone will identify this chip on his/her mainboard and write
it... If not, this mb isn't worth too much trouble :)
Click to expand...

Hmm. Your measurements don't sound like a match for the LM358.

This is the best picture I could find. Maybe your eyesight is
better than mine.

http://www.asrock.com.tw/product/intel/images/PEPRO-HT.jpg

When you pulled the chip, did the thickness and position of
copper tracks underneath the chip, suggest to you that the
chip is an opamp (low current device) or some other kind
of power device ? The copper in that area looks pretty big...

Paul
 
Paul said:
Hmm. Your measurements don't sound like a match for the LM358.

This is the best picture I could find. Maybe your eyesight is
better than mine.

http://www.asrock.com.tw/product/intel/images/PEPRO-HT.jpg

When you pulled the chip, did the thickness and position of
copper tracks underneath the chip, suggest to you that the
chip is an opamp (low current device) or some other kind
of power device ? The copper in that area looks pretty big...
Click to expand...

Just to finish the topic here is the conclusion :)

I guess this really is not LM358. Every integrated circuit on this
motherboard is marked as Uxx (xx is the number). And the transistors are
marked as Qxx. This little chip is marked as Q13, so it seems to be a
transistor, not the IC.

Tracks under the chip are thick (about 1mm wide), so this rather is a
medium power device.

I found some other Asrock mobos, they all seem to have such a chip
marked as Qxx. But on most of them it is a part marked as 4500M (and
googling for a while prooved, that this is a mosfet)

After some time of stairing at the large photo You gave me and searching
datasheets I think, that this chip may be a CEM942x or similar power
transistor.

Soldering as a replacement the 4500M gave me the desired effect - there
was about 2.55V voltage on a nearby mosfet, but the mobo still beeps
with a memory error (both on SDR and DDR).

Anyway it was fun to play - thank You all for Your time ;)
 
Just to finish the topic here is the conclusion :)

I guess this really is not LM358. Every integrated circuit on this
motherboard is marked as Uxx (xx is the number). And the transistors are
marked as Qxx. This little chip is marked as Q13, so it seems to be a
transistor, not the IC.

Tracks under the chip are thick (about 1mm wide), so this rather is a
medium power device.

I found some other Asrock mobos, they all seem to have such a chip
marked as Qxx. But on most of them it is a part marked as 4500M (and
googling for a while prooved, that this is a mosfet)

After some time of stairing at the large photo You gave me and searching
datasheets I think, that this chip may be a CEM942x or similar power
transistor.

Soldering as a replacement the 4500M gave me the desired effect - there
was about 2.55V voltage on a nearby mosfet, but the mobo still beeps
with a memory error (both on SDR and DDR).

Anyway it was fun to play - thank You all for Your time ;)
Click to expand...

I located a couple of other motherboards, that had similar devices
on them. What was puzzling me, was that there are two rows of
numbers on the device. One looks like "2030". The other is a
longer string, but seems to vary between devices. Is the
2030 part, the actual part number ? I agree it looks like a
MOSFET. I swear I've seen the logo before (the first character on
the longer string of characters), but I cannot remember
what company it is.

OK. I think I have it. This could be it. It gives me the
"2030" part and it is a plastic 8 pin DIP. (The Advanced Power
company also sells quite a few MOSFETs to Asus.)

http://www.a-power.com.tw/ProductDetails.asp?Part_No=AP2030SD

That part might be used as the push-pull output stage of the
termination supply for the DIMMs. I believe the termination
voltage is supposed to be mid-rail, and it has to be able
to sink or source current. It would basically be used to
turn an op-amp, into a low frequency power amp.

The termination supply would be designed similar to a part
like this. The 2030 would be the output stage of a discrete
version of this device:

http://pdfserv.maxim-ic.com/en/ad/MAX1510-AD.pdf

Paul
 
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