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motherboard diagram

Discussion in 'General Electronics Chat' started by 4electros, Aug 19, 2006.

  1. ParkingLotLust

    ParkingLotLust Member

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    If you can get your hands on schematics, I need to know what IC is at Q24 on a PowerColor Radeon 9550 256mb non-DV(s). It blew, and I need another one.
     
  2. OutToLunch

    OutToLunch New Member

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    Q24 denotes a MOSFET - are there any markings left on the part or did the top blow off?
     
  3. poopeater

    poopeater New Member

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    :confused: I'm not bragging. Hero initially asked why anyone would want motherboard schematics, and I was answering his question.
     
  4. dave

    Dave New Member

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  5. poopeater

    poopeater New Member

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    Like OutToLunch said, Q24 is some type of FET. I don't have that particular card, but you should look and see if you can tell what IC (if any) that Q24 is connected to. I'd guess that it's part of the power supply circuitry, and you can probably look at the datasheet for whatever IC it's connected to to tell what the characteristics would be for a replacement.
     
  6. Marks256

    Marks256 New Member

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    oh, ok. :)
     
  7. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    To help support his claim, he's posting from a major manufacturers IP address, so I've got no doubts as to the validity of his claim (or the fact he's not allowed to distribute them).
     
  8. Marks256

    Marks256 New Member

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    Yes, i belive him.
     
  9. ParkingLotLust

    ParkingLotLust Member

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    If I knew what the part was, I wouldnt have to ask :( When it blew (psu blew, took out the video card, and motherboard - fixed the mobo by repairing a trace) it put a little hole in the FET. Just enough so that I cant read what it is. Its an SO-8 if it matters. Ill do some checking with a magnifying glass later.
     
  10. OutToLunch

    OutToLunch New Member

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    I will go ahead and just assume that this is a MOSFET for a buck switching power supply. So, in SO8, it will either be a single FET or dual packaged. Remove the FET from the board and look at the pin pads. If the pads for pins 5 through 8 are shorted together and also the pads for pins 1 through 3 are shorted, then it is a single FET. Otherwise, pins 7 and 8 will be shorted and Pins 5 and 6 will be shorted for a dual packaged FET.

    I highly doubt that the FET would be a P-Channel, so that narrows things down as well.

    If the FET is a single, then find it's mate - it is very likely that the regulator is a synchronous buck and not standard. It is also highly likely that the blown FET will be from the same manufacturer as it's mate. I can't say that it will be the same FET though - the control FET is many times different than the synch FET.

    I would also trace back the gate signals to find the PWM controller IC. That will tell alot about what the supply is.
     
  11. ParkingLotLust

    ParkingLotLust Member

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    Its a single FET. Its pair is right beside it, and is marked 119N3S. That one is also a single. The only IC near it is U41 and is marked 1575 PNFE.
     
  12. waleed dongol

    waleed dongol New Member

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    hello , i am waleed from Egypt

    it is important to have a schematic diagram for mother board becase u may fix it when dameged
     
  13. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Modern motherboards are not designed for repair.
    No manufacturer will supply a schematic anyway.
     
  14. Space Varmint

    Space Varmint New Member

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    The very reason I got out of that business years ago was, suddenly Intel started sending out free schematics of mother boards for their latest embedded processors and then Compact joined in and others....I did not have anything to do anymore. I couldn't hide from free mother board schematics. So I went into radio.
     
  15. Jerr

    Jerr New Member

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    motherboard

    I'm trying to reconnect the power led and the power sw wire back on the motherboard for the switch to work, i have a E Machine Model number W3622. Thank you Jerr
     
  16. DMilardovich

    DMilardovich New Member

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    Hi everybody,

    I`m from Argentina, I was wondering if I could get the schematic of a Socket 7 Motherboard for educational reasons :)

    Do you think it`s possible ?

    Edit: My MSN is DMilardovich@hotmail.com, I would extremely apreciate your help
     
    Last edited: Feb 5, 2009
  17. LostQWERTY

    LostQWERTY New Member

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    Hi All,

    Im just curious about the motherboard design. I know most circuits on a MB are powered by 3.3V, 5V and 12V lines. I also notice a -5V and -12V supply that carry low current (1A or less) as compared to the + rails. On current MB (Pentium and newer) does this - rails are still being use on MB or they are just use to power accessory PCB (PCI, AGP card, etc). If so, can any one tell me what are the specific uses of this - rails.

    Thanks all.
     
  18. HiTech

    HiTech Well-Known Member

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    Do you think his employer is aware that he posts from their IP using the screen name "poopeater"?:confused:
     
  19. HiTech

    HiTech Well-Known Member

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    Well waleed, like it's already been said here that a vast majority of motherboard repairs are not done due to numerous reasons. In other words, you don't see stone masons running around the pyramids patching them up here and there... look at the Sphynx's nose! It's simply something that is better left alone.
     
  20. atferrari

    atferrari Well-Known Member

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    Is it your signature or are you saying that to whom? :eek:
     
  21. RCinFLA

    RCinFLA Well-Known Member

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    Modern CAD schematic and layout software makes a complete motherboard schematic for anybody but originator with linked files and particular CAD software next to useless. Yes, most CAD software can generate a multipage PDF file of the total schematic but it will be close to useless. There are multiple node labels used which you really need the original CAD software to track and trace out for you. You might as well have an Excel file with component and node number connections, it is about the same thing.

    Board developers have multiple people working on the motherboard and most only know about their little part of the overall design. A given IC will be broken up into small sections spreadout over multiple pages.

    You will go crazy with a PDF file tracking through a label link on multiple pages. By the time you get several pages deep you will have forgotten what you were originally looking for. If the guy that generated the PDF file did not specify text to be outputted as font characters instead of graphical stick renditions (which is usually the default output) you don't even have label search capability.
     
    Last edited: Sep 6, 2010

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