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Sometimes fails to POST, sometimes works fine

By spon
Jun 17, 2009
  1. Hello my name is Alex,

    I have followed the no post guide on this forum but have not solved my problem, specially since I get unconsistent results.

    My 2,5 year old Dell inspiron 6400 (e1505) out of warranty

    CORE 2 DUO T7200
    15.4" WXGA (1280X800)
    RAM 2048MB (2X1024) 667MH
    120GB SERIAL ATA
    9 CELL 85W/HR LI-ION
    ATI MOBILITY RADEON X1400
    WINDOWS MEDIA CENTER XP SP3

    About a month ago it started to fail to POST. after several attempts it would finally boot. If I restart it works fine, only on Cold boots will it fail to POST, and after several attempts or just leaving the fans running for 10 minutes and booting again it will work.

    When i works i have run full dell BIOS diagnostics and everything is fine.

    By pressing mute and power i get LED feedback on the POST failure

    support.dell.com/support/topics/global.aspx/support/dsn/en/document?c=us&cs=19&dl=false&l=en&s=dhs&docid=DBECF64CFEDA449398CB9E859D4944A5&doclang=en#1

    I normally get a still flash flash code which means:
    Description: Turning on the LCD panel (after video configuration).
    Actions:
    1. Reseating the LCD cable.

    2. Replacing the LCD panel.

    3. Replacing the video card.


    I have followed the no POST guide on this site,
    Dispersing internal Voltage
    resetting the CMOS (by extracting the coin battery for a minute)
    Switching around the RAM
    Opening up the laptop and securing the lcd to video card plug

    All of these produced irregular results, sometimes it works others it doesn´t.

    Sometimes while pressing mute and power the computer boots into bios diagnostics mode showing a flash flash still LED code witch means

    Description: The video card is preventing the system from completing POST.
    Action:
    1. Replacing the video card.

    2. Replacing the system board.

    but it boot without problems into the diagnostics test, passes all test and then boots normally into windows.


    Any help will be greatly appreciated. It is not currently a fatal problem, since it always boots after 10 minutes running (without booting) But i don´t want my motherboard dying suddenly, or if it is a connection in the LCD, i would like confirmation before pulling it all apart to check loose cables. I have taken apart computers but am certainly not an expert.

    Thank you

    Alex
     
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    Replace the Dell power supply
     
  3. spon

    spon TS Rookie Topic Starter

    I forgot to mention, i have tried using all the combinationes, battery alone, charger alone and battery and charger, an they do not change the outcome of my boot process.

    I have read in other forums that power supply are the most probable cause of these problems, but in my case the computer receives power always, the power LED always turns on and cpu fans and HD work (since i can hear them).

    I have tried booting without DVD drive, HD, RAM etc. and it doesn´t change anything, so i think it might be, either MOBO, Graphic card or LCD, but since they all pass all tests i don´t know what to test or fiddle with.

    I seems like the computer has to warm up, before booting, i´m going to have to install a starter on it for those cold winter mornings.

    Thanks again for your help.
     
  4. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    This is a laptop? The hard drive or memory may be causing this
     
  5. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

  6. spon

    spon TS Rookie Topic Starter

    update

    Most of you seem to think it is power supply related, yet i have to insist that the computer powers on, but then fails to POST. I have reached a stable situation where i turn on the laptop,it fails to boot, but the power light is on, and it is powered, I wait about 5 minutes then power off and power on again to a normal (a bit slow) boot, a further windows restart leaves the laptop fully functional.

    I am afraid this is a sign of a future failure, or something that i can fix now, before it becomes permanent, and that is why i ask for your help.

    Alex
     
  7. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    "Most of you seem to think it is power supply related"...

    Most of us thought this was a desktop computer. Laptop power issues are much different than for desktop problems. i really think the motherboard is at fault here. Can you remove the CMOS battery and clear the motherboards bios? If not, take the laptop in for service. A motherboard change will be expensive, but it is done all the time
     
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