From: Al on 27 Oct 2009 14:33 On Oct 28, 4:34 am, Paul <nos...(a)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
From: Al on 27 Oct 2009 14:37 On Oct 27, 10:09 pm, Grinder <grin...(a)no.spam.maam.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. > > If you short the power button pins on the motherboard's front panel > header, will it start up? > > I'm sorry I can't be more specific about where those pins are as I don't > know what motherboard you have. (I don't have a badcaps.net login.) If > you identify the motherboard, I can give you a more specific answer. Yep good suggestion and yes I have done that.
From: Grinder on 27 Oct 2009 17:23 Al wrote: > On Oct 27, 10:09 pm, Grinder <grin...(a)no.spam.maam.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. >> If you short the power button pins on the motherboard's front panel >> header, will it start up? >> >> I'm sorry I can't be more specific about where those pins are as I don't >> know what motherboard you have. (I don't have a badcaps.net login.) If >> you identify the motherboard, I can give you a more specific answer. > > Yep good suggestion and yes I have done that. Did the PC startup? I guess it must not have if you still consider the motherboard to have a problem. If there is a chip that is bad, as you've suggested, it's unlikely that you'll be able to affect a repair. Since you've tried another power supply already, it's getting near to the point where you have to cut your losses.
From: Pennywise on 28 Oct 2009 02:17 Al <bigal.nz(a)gmail.com> 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. Or the power supply, http://www.pcguide.com/ref/power/sup/funcPowerGood-c.html Monitor the Gray wire (+5V & +3.3V is ok). -Also- You short purple (not Green, Green is the wrong wire). "Why the computer/fan does not turn on after flipping the power supply's switch to the ON position? ATX power supplies differ from AT power supplies in several important regards. Major among these is that ATX supplies depend on logic circuits on the motherboard to turn it on. Once the power switch is flipped, the power switch on the ATX power supply (some ATX power supplies do not even have such a switch), the ATX power supply sends a 5V 720MA current to the motherboard through pin 9 on the power connector. That current is for WOL (Wake-up On Lan) and power on circuits. A power-on jumper on the motherboard connects to the pushbutton located in front of ATX case. When the pushbutton is pressed, it sends a signal to the motherboard, which in turn notifies the ATX power supply to turn on full power. The location of the power-on jumper on the motherboard is manufacture dependent. One needs to read the motherboard manual to locate that jumper. At any event, do not try to manually jump-start the power supply without attaching the motherboard. The power supply is expecting certain sensing circuit feedback to regulate the output voltage, manually starting it without attaching it to the motherboard could cause damage to the power supply." http://www.bluemax.net/techtips/ATXPowerSupplyWiring/ATXPowerSupplyWiring.htm I have always linked this page, it appears to be no more. It was a very good site on ATX power supplies, I have the web pages of interest if you want them. I have a digital DC voltage display with two clips on long wires, just made for something like this. I was given two of them, each had instructions to wire them for different functions - I went with DC voltage. - very nice to have handy to monitor voltages.- -- You've got three months to grab what you need. http://torrentfreak.com/the-pirate-bay-ordered-to-delete-torrents-091022/ And http://gizmodo.com/5387909/hulus-glorious-free-days-are-officially-numbered
From: edfair on 27 Oct 2009 21:43 Also a good possibility that there may be a RC network into whatever the latch happens to be. Could possibly be traced with a VOM. If so, the incoming signal line will split off separately for the shutoff function.
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