🚀 go-pugleaf

On Oct 28, 4:34 am, Paul <nos...@needed.com> wrote:
> Al wrote:
> > Hi Guys,
>
> > I have got a mobo here that is dead. I have done all the usual stuff
> > like trying new PSU, bench testing etc. Its dead - as in no fans, no
> > nothing when you hit PWR button - PSU doesnt even come on.
>
> > I connected the ATX molex from the PSU and shorted Green (PWR ON) with
> > GND on the molex and the PC came on. All seemed fine.
>
> > I think there is a IC on the motherboard between the PWR BTN headers
> > from the power on switch and the ATX header on the mobo that tells PSU
> > to start up.
>
> > I am trying to find this IC.
>
> > I have attached a image of the mobo with some of the IC's that seem
> > possible labelled.
>
> >http://www.badcaps.net/forum/attachment.php?attachmentid=12082
>
> > Interested to know if anyone knows which IC controls the PSU and tells
> > it to turn on? Someone else suggested this function was handled on the
> > CPU since P4, but I am not sure about that.
>
> > Thanks
>
> > -Al
>
> > RT9237 :http://www.alldatasheet.com/view.jsp?Searchword=RT9237
> > 93705CF :http://www.ic2ic.com/search.jsp?sSe...3705CF&prefix=9
> > 952001AF :http://www.alldatasheet.com/view.js...chword=952001AF
> > 2N03L :http://www.alldatasheet.com/view.jsp?Searchword=2N03L08
> > LD117 :http://www.st.com/stonline/products...fo/ld1117_1.htm
> > RT9602 :http://www.alldatasheet.com/view.jsp?Searchword=RT9602
>
> Any chance of posting the badcaps image, on one of the free image hosting
> sites ?
>
> In terms of your notion of figuring it all out, based on a picture,
> that isn't likely to happen.
>
> I have three reference schematics here, and they all implement that
> function in a different manner.
>
> First off all, there is a whole chain of logic associated with that
> function. It includes the Southbridge (Wake on USB keyboard, Wake on
> scheduled RTC time, Wake on PME from PCI bus), the SuperI/O
> (Wake on Ring on serial port, Wake on PS/2 keyboard keypress), plus
> some external jelly bean logic. Those chips contribute reasons why
> the power should be switched on.
>
> One schematic, uses a 2N3904 transistor as the interface to pin 14
> on the 20 pin ATX power connector. The interface is open collector
> logic, so a transistor can be used as the driver.
>
> Another one, uses a Fairchild 14 pin TTL logic chip, with open
> collector output drive, to control the signal on pin 14.
>
> The third schematic uses a custom chip, with no data available,
> to drive the signal directly.
>
> So even if you do post a picture of the motherboard, and the
> resolution of the picture is high enough to read all the chips,
> it still may not be possible to guess at the method. Chips don't
> have to be placed in proximity to the driven thing. So you
> won't necessarily see the "guilty party" sitting right next
> to the 20 pin connector. There is no requirement in a layout,
> that a driving chip be placed right next to the load. It
> could be all the way across the motherboard, on the other
> side of the board.
>
>     Paul

Paul,

Thanks for the very detailed replay.My bad for not remembering bad
caps wouldnt allow you to view the image.

Here is the image: http://img101.imageshack.us/img101/4540/dsc04544a.jpg

The motherboard is a Elite group L4S5MG/651 + V5.01

In addition to the other components:

GS 78L05N (just aboce molex, 3 pin volt regulator)
NEC K3296 MoSFET
STLAB LD1117 (volatage regulator)

But the one that seemed most likely was the RT9237 MULTIPHASE DC/
DCCONTROLLER FOR CPU PWR SUPPLY

This help any?

And for those suggetsing bin it, yes I can do that, but there is no
learning in that!

-Al