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Inspiron 1000 - help to identify damaged chip

By stevewes
Jul 9, 2009
  1. Hi all, I wonder if anyone can help me with an old Dell Insprion 1000 laptop.

    This stopped booting so I took it apart and found a 8-pin chip on the underside of the mobo near the power jack appeared to be seriously overheated - location shown below under the yellow mark.

    img.photobucket.com/albums/v383/stevewes/board.jpg

    I was looking on ebay and found someone else selling a damaged board with the exact same problem so maybe a common issue? Another seller with a good board read the markings off the chip for me (mine is too badly scorched to read). He tells me the markings are "4835 L44A". Does anyone know what this is (eg is it a, EEPROM device in which case I may as well give up now as no code to program a new one), or does it have some other function - if so where can I get one because I've googled the part code and not found anything.

    Thanks to anyone who can help / advise!!
     
  2. raybay

    raybay TS Evangelist Posts: 7,241   +9

    Isn't it best to use your Service Tag number, then go to the Support site at Dell for advice or a motherboard replacement ? or just order a replacement on eBay ?
    It is pretty difficult to replace the chip yourself unless you are very skilled chip techniques, and can identify the EEPROM, as they are made in many configurations that cannot be easily identified and changed.
    Alternately The motherboard has ID numbers around the edge, and near the center you can use to buy identify the motherboard in preparation to find a replacement As you may know,
    EEPROMS come in many different sizes and shapes, and some come on daughter boards or other devices that have multiple chips. Unless you have the specific device that generates the code and voltages (installs or writes the code to the chip) for the EEPROM, you are sunk... If you are a programmer with the hardware that does the job, you already know this. But you can hardly ever exchange out the chip and make things work.
    EEPROM chips would rarely be exposed to a heat source great enough to cause serious overheating damage. If you have been trained to write the code to that particular device, then you should be able to spot it.. On an individual basis, this usually requires lab or bench equipment. You can, with this knowledge, alter the value of certain cells without needing to erase the programming on other cells. Sections of data can be erased and replaced multiple times without needing to alter the rest of the chip's programming, but this is not a high heat operation, and the EEPROM is not near a heat source on the board.
    Data stored in an EEPROM chip is permanent, at least until the user decides to erase and replace the information it contains. Obviously the data stored in an EEPROM chip is not lost even when power is turned off. There are specific techniques and equipment needed to erase and rewrite a specific EEPROM chip... Unplugging (desoldering) one EEPROM and replacing it with another does not work unless you know the rest of the code. Erasing it without recoding will not work either.
    To configure an EEPROM chip, an electric field produced by the charge pump is applied locally to cells marked for modification. Nowadays the number of times EEPROM's can be reprogrammed or altered is usually limited, but you still need a die and the knowledge of each EEPROM and its voltage requirements.
     
  3. stevewes

    stevewes TS Rookie Topic Starter

    Thanks for the reply raybay.

    I'm sure asking Dell for a replacement mobo would cost far more than the laptop is worth, even if they are still available.

    However, done a little more digging on the part number and it appears that it's a MOSFET device, so hopefully a straight replacement will fix the problem (which I suspect was caused by a loose screw inside the case causing a short). I've replaced plenty in surface mount chips in the past so that shouldn't be a problem, just need to source the replacement.
     
  4. raybay

    raybay TS Evangelist Posts: 7,241   +9

  5. raybay

    raybay TS Evangelist Posts: 7,241   +9

    As for the motherboards, we buy tested Inspiron boards for as low as $59.95 with shipping and have paid as much as $119.99 with shipping... That may be high unless your time is worth anything. Average price for our shop is $69.99 which includes ground shipping, and we find that quite reasonable. An untested board only costs us $29.99 plus shipping... and most of our suppliers are found with an eBay search.
     
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