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Toshiba L500 LA-4982P powers up - no video

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    Toshiba L500 LA-4982P powers up - no video

    Hi, here I have Toshiba Laptop L500 LA-4982P.After turning on - power led light up, but no video on LCD or external display. It has dedicated AMD graphics (removable separate PCB ).
    tried so far:

    1.Light re-flow all BGA chips (usual reaching 150C), this is easy technique to identify BGA solder problems but not fix them. - some thing happening.
    2.Remove all external devices - some thing
    3.Remove Dedicated graphics(it has integrated intel graphics as well) - some thing
    4.Check for bad caps - no nec/tokin caps found, ESR looks good on all larger caps.
    5.Checked DC-DC ripple voltages - some 50mV, some 100mV p-p. - not sure if it is bad. 100mV sounds a lot, please confirm this.
    6. Checked SPI bus to bios flash chip - data bursts about once a second in power off state, Continuous data flow in power on state (Is it right?)

    Not sure if ripple voltage is too big and I have no idea if constant data flow from spi flash chip is right, I thought ROM was read from flash chip at system start at once.

    Any Ideas guys ?
    Last edited by akarta; 11-24-2015, 08:37 AM.

    #2
    Re: Toshiba L500 LA-4982P powers up - no video

    I think I have posted in wrong section This should be moved to Laptop troubleshooting

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      #3
      Re: Toshiba L500 LA-4982P powers up - no video

      I have managed to fix my problem. Flashed bios from this post:
      https://www.badcaps.net/forum/showthread.php?t=47094
      File had ROM extension and was few bytes too large. Had to remove everything after 0x001fffff(to make 2MB file size) with hex editor and saved as *.bin. Then I compared old bios dump with new created one. Beginning and end matched so I was sure that I made good bios file for flashing.
      I don't have programmer so I improvised. Used Raspberry pi which collected dust for long time and flashrom software for linux. This software is amazing, it support a lot of interfaces and hundreds of flash/eeprom chips.
      After soldering bios back to motherboard it started POSTing. Yahoo!!
      If anybody has similar problem this may help you too.

      Comment


        #4
        Re: Toshiba L500 LA-4982P powers up - no video

        great job. thank u

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