What are basic diagnostic tests on a Windows laptop that won'tboot?

Discussion in 'HP' started by Calia, May 26, 2014.

  1. Calia

    Paul Guest

    If you're serious about doing that, *don't* use the
    oven that you use to prepare food.

    Find a used toaster oven, keep it outdoors while
    attempting the repair. The stink of melted plastic or
    burned materials will stay with your used toaster oven,
    while the family food oven is kept safe.

    In an industrial setting, the duration (hold time) and
    temperatures are all strictly controlled.


    As the posters note in your article above, if you heat the
    entire motherboard, the electrolytic capacitors could
    suffer. This is why a real re-work station uses a hood,
    so the hot air only goes to the chip being repaired. If you
    own a hot air gun, you can make a home made hood out of sheet
    metal. For temperature monitoring, you could use a
    thermocouple connected to a multimeter.


    Paul, May 26, 2014
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  2. Calia

    Charlie+ Guest

    You cant' reflow a motherboard and get away with it, you can sometimes
    replace a single chip if you know exactly what your doing and exactly
    which chip is the problem. Many laptops dont have plugin processors,
    there is no chance of replacing a soldered-in one!
    Suggest you head for the bin with this one having taken the hard drive
    out and lifting off any files you need to keep.
    If you really want to pursue the problem, there is a diagnostic board
    you can get for not much money from China, which plugs into the parallel
    port (which has direct access to the BOIS boot) and can watch every step
    of any bootup, it remembers the 4 digit codes for every step in the
    sequence so you can step through and interpret exactly where the BOIS
    stops booting, cheap kit - but not for the faint hearted, check your
    laptop has a parallel port!
    See : eBay item number: 400514258135
    Charlie+, May 26, 2014
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  3. Calia

    Ken Guest

    You have received a lot of useful information and suggestions, so what I
    am about to say may be for naught: I have two G72 laptops. One I
    bought new and experienced much the same type of problem as you are
    after the warranty ran out. Being that I am one who cannot accept a
    device is not repairable, I dug into trouble shooting and repairing my
    laptop. At first I opened it up and inspected the connections because
    the problem was intermittent. I would disassemble the computer,
    reassemble it, and it would work for a time. Then it would fail again.
    Without going into great detail of all the steps, the solution to
    fixing this computer was to re-solder the connections at the power
    switch board. There appears to be an opto isolator on a daughter board
    where the switch is mounted. It takes a steady hand and a low wattage
    iron, but this computer has not failed in a couple of years since I
    touched up the connections. I think I fixed it.

    After having fixed the above computer, I purchased another G72 computer
    on Ebay where the seller was encountering the same failure as mine. I
    bought it for little, and thought I would use it for parts if my
    computer ever failed. When I received it, it DID NOT include an AC
    adapter. I plugged in my adapter to the computer and everything
    worked!! That has been over a year now.

    So what can one learn from the above? First off there appears to be
    some experiencing such failures that are attributed to the power switch
    board. There are such posts on the web. Second, if the adapter
    delivers less than the proper level of voltage to the computer, it too
    will fail in a similar manner. Measuring the voltage with a volt meter
    is not going to work unless you load it down sufficiently. If it were
    my computer, I would borrow a power adapter that you know works on that
    model computer. If it does not solve the problem, suspect the power
    switch board.

    There are no guarantees as to what will solve your problem, and the fan
    running seems to contradict my experience, but a lot is happening when
    you start a computer. Any of them failing will negate the boot process.
    Good luck.
    Ken, May 26, 2014
  4. Calia

    Calia Guest

    Just because I could, I tried booting to Knoppix, but it didn't even
    get to the BIOS screen, which, if the CPU is reporting itself bad,
    would be the case.

    I don't think Windows 7 would fare any better, but, I don't have a
    Windows 7 boot disk anyway.
    Calia, May 26, 2014
  5. Calia

    Wolf K Guest

    I've read all the other advice, all of it good if you're comfortable
    messing with hardware, etc.

    However, your _first_ concern should be to get all your data off the
    disk drive, and that can, and IMO should, be done without repairing the
    machine. IMO best bet is to take the machine to a shop that can deal
    with it. Then you can decide whether repair (by yourself or the shop) is

    HTH & Good Luck,
    Wolf K, May 26, 2014
  6. Calia

    Wond Guest

    Before you have disassembled anything, shine a flashlight (electric torch)
    at the screen, and watch closely as you power up. Maybe just the backlight has
    Wond, May 26, 2014
  7. Calia

    Calia Guest

    This is good advice, as had been all the prior advice.

    I am heading down to Radio Shack today, if they're open, to pick
    up an SATA/ATA USB adapter, which will make it very easy to get
    all the data off the hard disk drive.

    I've done that step before, and, even better, I recently
    made a backup of my data hierarchy only about a month
    ago, so there really isn't much data that I need to
    back up incrementally anyway.
    Calia, May 26, 2014
  8. Calia

    Calia Guest

    I tried that, and saw nothing. Even in the dark.

    I think the single blink of the numlock and capslock indicating a bad CPU
    (or the power to it) is the issue.

    Most people here seem to indicate that the CPU itself didn't fry, but,
    that the solder joints honeycombed, and eventually cracked.

    At least that's what I seem to have gotten so far out of the
    Calia, May 26, 2014
  9. Calia

    pjp Guest

    The manufacturer's site may have some info on what you "see" and "hear"
    depending on what's wrong. Least used to be "x" beeps meant this and
    "y" beeps meant that type idea, maybe lights do similar?

    Internal power supply likely provides a number of leads with varying
    power. Could be it's failed on one or more of them but not all hence see
    leds lit on some keys?

    Again an experienced shop would know how to test all that, I don't. I
    also don't really like taking laptops apart IF I also have to put it
    back together and have it run :) I solder with a blowtorch LOL
    pjp, May 26, 2014
  10. That probably will work, especially since the drive is not failing and
    there's little risk of losing anything on it.

    In the future, you might consider doing an image backup instead. I
    use Acronis True Image 2014, but there are free drive cloning programs
    that will also work:
    Some of the benefits of image backups are:
    - Speed. I just did an SSD to USB 3.0 backup running at 6
    GBytes/minute. Typcial for older machines and USB 2.0 is 1-2
    GBytes/minute backup.
    - It backups up literally everything. Nothing is missed. That's
    great for programs the dump files in unusual places or strange stuff
    in hidden partitions. Also works with UEFI boot.
    - In this case, it will also get the recovery partition, which you
    might need for a reinstall. The alternative is to order the recovery
    DVD's from HP (about $30).
    - etc...

    I'm at the point that everything that is brought to the shop usually
    gets backed up twice; once on arrival and once when it's done.
    That's about 6TB of drives show. There is probably another 5TB of
    drives that I've since the picture was taken. What makes this
    practical is the speed of the backup (and restore).
    Jeff Liebermann, May 26, 2014
  11. "Calia" wrote in message
    If you're near a computer-supply store, you might want to look for Vantec. I
    can recommend them from personal experience.

    William Sommerwerck, May 26, 2014
  12. Yes and no; it takes practice!

    Step by step through that video:

    melting the solder on the pins of the IC with a hot air blower.
    Personally, I'd have some Kapton tape (like the yellow tape visible near
    the top of the video around just after 7 minutes in) over the other
    small components around: not so much as to keep them in place - if
    they're decoupling capacitors, it _might_ not matter too much if they're
    lost - as to stop them going off and shorting something else. It's easy
    not to detect these almost microscopic components.

    Removing the IC. I'm pretty certain there was a skip in the video, as it
    seems to disappear by magic - one moment it's there, the next it isn't.
    The most important thing is to make sure all the solder is really
    melted: if it isn't at just one or two pins, you can pull off tracks
    (which are the devil to repair) when you pull the IC off. Ideally it
    will just blow away.

    Cleaning up the solder pads. That's what he's doing with the solder
    braid (the copper woven strip) and soldering iron. Basically, you want
    to clean the pads until they're flat, no solder (other than a very thin
    flat layer).

    Applying solder and replacement chip. It looks like he applied solder
    and then reheated it all with the hot air again. I'm sure that can be
    made to work; the way I usually do it is manually tack two opposing legs
    to hold the chip in place, then go around chasing a blob of solder
    around the remaining legs: amazingly, this does work, if the
    solder-resist is in reasonably condition. Lining the chip up before
    tacking is the difficult bit - doable, just takes patience (and a second
    or third try if it moves during the tacking: you just have to groan and
    do it, don't go ahead and assume you can fix it after you've soldered
    _all_ the legs).

    The second half of the video seems to be replacing a surface-mount
    connector, by much the same means, though I think he does use tacking
    this time.

    I'd agree with those expressing doubt as to whether it's worth it, and
    try with an external monitor first.

    (Also, my own - extremely limited! - experience of laptop repair has
    been that cracks - in the solder joints or the PCB tracks around them -
    in the vicinity of the power input connector can be the problem: and
    lights can still come on, just there isn't enough power getting through
    to do anything else. If it gets to a dismantling and possible soldering
    activity, I'd reflow the solder around those before anything else: a lot
    easier than the finer chips. My experience replacing chips is genuine
    [avionics], but not with laptops. And I wouldn't expect to be able to
    reflow a ball-grid array.)
    J. P. Gilliver (John), May 27, 2014
  13. This model?
    $27 from NewEgg.
    Ouch. Note that I'm buying USB 3.0 these days because it's becoming
    common and the speed improvement is worthwhile.

    Cheaper on eBay:
    Jeff Liebermann, May 27, 2014
  14. Calia

    Calia Guest

    I was wondering what that was, as he seemed too close for it
    to be a flame burner.
    Calia, May 27, 2014
  15. Calia

    Calia Guest

    I had never heard of this "kapton" tape!

    Googling, I'm still not sure what it is, but it must be a great
    Calia, May 27, 2014
  16. Calia

    Calia Guest

    I hadn't even thought of that!

    It's a great idea.

    I have one at work, which I can test out tomorrow!

    Calia, May 27, 2014
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