Dell inspiron 5100 will not post

By Tdog
Feb 27, 2008
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  1. Hello, I really need help with this one.
    I bought this broken laptop it will not post.
    Just a black screen, when I try and boot it up all three lights on the front come on for a sec then just the power light is on

    I tried to turn on the Numlock but the light wont toggle for the keyboard.
    I hear the fans and I can hear the HD spinning up.

    I tried to plug in a monitor into the external port but its still black.

    It has 2 memory slots both filled with 256megs each I removed one switched them around, still nothing

    The thing seems to charge when plugged in the charging light on the front comes on and blinks.

    The DVD or CD drive seems to spin up and read a disk when its in there.
    Of course you cant see anything but?

    I am running out of Ideas.

    I wouldnt think that both Memorys could be hosed.

    Only thing I can think of is The processor,,Mother board,, Maybe the video card?

    Are there any known issues with these that could highlight one of these 3 possiblitys?

    Any help on this would be great thanks in advance :confused:
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,732   +156

    Try booting on AC with the battery out
  3. Tdog

    Tdog Newcomer, in training Topic Starter

    Thanks for your help I tried to boot the thing without the battery.
    Same thing no post.
    I can hear the HD and CD/DVD spin up just nothing comes up on the screen from the LCD or the external port.

    No beeps no nothing.

    Anything else I could try?
  4. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,732   +156

    First pull out the hard drive and see if the laptop POSTs. Then pull the CD and see if it POSTs. If it still has no display, the motherboard may be gone
  5. lamo

    lamo Newcomer, in training Posts: 570

    Tmagic650 et al. you guys misunderstand the POST procedure itself. if laptop won't show anything on the screen it doesn't mean that it has no POST. you can fully check the POST procedure only if you use POST-card. usually the POST codes are thranslate to port 80h to Mini-PCI bus, or port 78h - this is LPC bus(actually, it means LPT port :)). so, if laptop won't show anything it can be stopping on memory testing(A0 code, A9 code), or video subsystem initialization.

    to subj. the problems in this compal platform are: dead southbridge, destruction of soldering under northbridge and CPU socket(this is developing error, which connected with unstandart MOSFETs regulators of CPU voltage), KBC controller dying, video card problems(due lack of heatsink).
  6. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,732   +156

    Speak for yourself lamo,
    I know many times laptops are not set to show POST messages on boot up. You can usually see a brief flash of light on the LCD though. Through experience, a tech can tell if there's an attempt to POST or not...

    "to subj. the problems in this compal platform are: dead southbridge, destruction of soldering under northbridge and CPU socket(this is developing error, which connected with unstandart MOSFETs regulators of CPU voltage), KBC controller dying, video card problems(due lack of heatsink)"...

    Here in the US this whole paragraph means one thing: BAD MOTHERBOARD! It will most likely lead to no repair. Laptops are getting cheaper and cheaper. I only consider replaceing laptop motherboards when the laptop originally cost above $1000, or the customer insists on the repair. (It amazes me how some people get attached to things)
  7. lamo

    lamo Newcomer, in training Posts: 570

    Tmagic650, you aren't right. the POST procedure begins after RESET signal(PGOOD analog in desktop MBs). KBC controller or in rare cases southbridge generates reset signal. the beginning of POST is possible ONLY after successful RESET signal.and in addition: IBM R41(intel chipset) the LCD blinks after powering on, but i see a stuck RESET, which means NO POST. how do you comment this situation?

    BTW, do you have the Mini-PCI POST card for laptops?
  8. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,732   +156

    "BTW, do you have the Mini-PCI POST card for laptops?"...

    What POST card do you use? I have a couple of laptops here that are "dead".

    I've used standard PCI POST cards for desktop computers, but they always ended up unused in a drawer, because when a data bus was shorted, the POST cards were useless
  9. lamo

    lamo Newcomer, in training Posts: 570

    i didn't say anything about desktops. desktops and laptops are too different.
    well, my practice shows some other things. it is important to see if we have right reset signal passing, then #clk, 3.3v, 5v. depending on these data we make a conclusion about repairing. of course if laptop won't turn on(i.e. no reaction on power button) - this is another situation.
  10. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,732   +156

    "i didn't say anything about desktops. desktops and laptops are too different"...

    No, but I did... Actually desktop and laptop motherboards operate very much in the same way POST wise. Also you didn't mention what MINI PCI Post card you have. I have Googled the card and they range from $35 to $1200
  11. lamo

    lamo Newcomer, in training Posts: 570

    yes, they operates the same way DURING POST. but electrically they are very different and POST codes means another values in some cases. i have noname Mini-PCI card =) i spent 60$ for it. it can show rst,clk,3.3v,5v and of course post codes. also i have some chinese LPT post card(40$).
     
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