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ASUS Q302L won't boot

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    ASUS Q302L won't boot

    Hello all,

    I got a not working laptop some time ago that was given to me... The previous owner said he had dropped it while it was running and broke it. There is a very small faint dent on the outside case of the monitor where I believe it hit when he dropped it. Since then, it hasn't been functioning correctly and acts broken 95% of the time. I can't quite remember all the details as it has been a while but I'll try to recount them...

    (Please keep in mind the Windows 10 OS didn't function at all on the HDD. I think the HDD works but I never had time or tools to play with it.)

    First, it refused to boot at all. I don't think we even got a power led light when we would press the power button. It wouldn't charge correctly either... So the first thing I did was go online and try some yoututbe videos telling me to take out the battery and cmos battery. We tried that and viola! The battery charge light, power led light, and power switch button came back to life.

    Next, we tried booting... The power led light came on, the hdd light came on (for about 5-10 seconds), and you could see the backlit laptop screen turn on but no actual light or images were present. It would just hang there with the power led light on, and access the hd for about 5-10 seconds. Also important to mention is no power to the caps lock led light during any of this. Afterwards, the power led light would remain lit, and the screen completely blank. We tried plugging it into a monitor and rebooting but with no success. It would just hang there, and after about 30 seconds the fan would randomly turn on and start to increase in speed slowly until it was hitting full blast. Sounds pretty toasted right?

    After trying this about 5-10 more times, eventually I reopened the case and disconnected the battery and cmos battery again. Closed everything, retried to boot and... Still nothing. Tried it again. And again... And again and then finally it randomly decided to work. It seemed to be relative to how I positioned the laptop screen, as it puts a slight amount of force down on the laptop chassis. But anyway, this boot process was very similar to before except for two things: 1, the laptop actually worked, and I could get into BIOS. and 2. the caps lock led would fire up for a second after pressing the power button. If I saw the caps lock led come on, the screen would be sure to fire up.

    I think the first time I got it working like this it randomly died after about a minute or two of usage within BIOS. (But that only happened once or twice during the time I've been toying with this.) I tried to boot it back up and got the same power/hdd led light combo I would normally get - no power to caps lock, no actual image on screen, and the fan that would turn on after about 30 seconds. Basically, sometimes it would boot correctly with the caps lock led lighting, and other times it would be the same drab no nothing boot without any power to the caps lock led or screen.

    One day I took everything apart, put it back together, booted correctly into BIOS and let it sit there. No problems, it didn't crash randomly, and I rebooted it 2-3 times and it went straight into BIOS like a good working laptop each time. The 4th time it reverted into the original state of not working. Frustrated, I packed it up and put it away.

    When I first worked on this... I noticed I was missing some screws inside the motherboard. It came that way, no screws holding down the back snap on cover, and about 3 screws missing from inside the motherboard. I figured maybe it wasn't booting correctly because of a ground issue... So eventually I finally found some replacement screws and put them in the motherboard. And this was my greatest mistake with this laptop so far... As I left the battery plugged in to the motherboard while doing this. Big mistake. The process was nearly complete, and I had one more screw to put it by the fan. As I went to twist the screwdriver to tighten the screw, somehow I popped the screw out and it fell onto the motherboard. I went to grab it with my fingers and.... Sparks! After screwing everything in... No dice. Same old scenario I typically had, no caps lock led light up, no BIOS, just a power and hdd led light on, and after 30 seconds the fan would turn back on.

    Except now, since dropping the screw and causing sparks, I haven't been able to even get the caps lock light/BIOS/screen to even show up. I've tried this another 30 times and its always the same result as the original... power led, hdd light, fan after 30 seconds, but no caps lock light, screen, or BIOS splash screen. It's just remained toasted, and all my finagling with it doesn't make it work at all. No matter how I hold the screen, or how long I leave the battery/cmos battery unplugged, I just can't even get the BIOS to turn back on.

    I wasn't sure why this was at first, but after doing some reading it sounds like the processor/GPU needs a reflow? But after those sparks I'm starting to think I shorted out the whole GPU chip or some other component on the motherboard. Maybe the processor chip is ok as I still get HDD led lights and power led lights and after 30 seconds a spinning fan? I am completely incompetent and unprepared for this but I'd like to try and fix it. I can spend a little time on it and I can do tests with a multimeter, but I don't have a solder station, any computer repair tools, spare caps, etc, and am not really sure where to begin or start on how to fix it. I downloaded the boardview program, and I believe I got the correct boardview file for this motherboard, but am not sure where to go from there.

    Can anyone tell me what the next step on this is to fix it? Anyone not so busy who knows what they are doing who might want to repair it?



    Attached Files

    #2
    Re: ASUS Q302L won't boot

    Those are among the worst… This kind of issue can sometimes be caused by BIOS although if it started happening right after the drop it's probably not that. As for the second damage from the screw shorting something, the BIOS is nearby so, you never know… All the other parts are not populated.
    This laptop doesn't have a dedicated GPU, the green are is where it should be put.

    If it is really drop damage, RAM chips (most likely has soldered RAM on the motherboard) or CPU may have come loose.

    As for the standard troubleshooting steps first thing to check would be the voltage on CPU VCore. Can be check on the inductor near the CPU.
    Attached Files
    Last edited by piernov; 01-10-2019, 12:00 PM.
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    Comment


      #3
      Re: ASUS Q302L won't boot

      Who hoo! Thank you! Now I have a place to start...

      So I just want to ask.. I have a cheap multimeter from a hardware store. How do I go about testing this CPU Vcore inductor? Let's say I find a pin diagram for it or it's in boardview, will a regular multimeter do? Or do I need something like an oscilloscope?

      Do I hold one line of the multimeter to one side of the inductor, and the other to the fan screw in order to test each side of the CPU Vcore inductor? It seems there is a standard way to test these pins without worrying about creating a short?
      Last edited by shotthruthemb; 01-11-2019, 12:44 PM. Reason: I meant inductor not chip

      Comment


        #4
        Re: ASUS Q302L won't boot

        You only need to measure voltage so any multimeter will do (as long as it has decent probes to make contact with the inductor's lead). It has to be set in voltage mode. If it is a non-autoranging multimeter, you have to set it to the 20V or 2V range.
        You need to put the red probe on the inductor lead's that face the CPU (toward the right on the picture).
        And the black probe on a ground point such as the USB port shield. The fan screw should be a ground point as well.

        The laptop needs to be turned on for this measurement.


        I'm attaching the boardview as well.
        Attached Files
        OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

        Comment


          #5
          Re: ASUS Q302L won't boot

          Alright! Sorry for the delay... But I got something... I couldn't find the inductor/CPUVcore on the boardview file, but when measured with a multimeter with red on the inductor and black on ground as you said, I got 1.79v at my 20v setting for the inductor near the CPU. I only measured one side... I guess I should have done both. But this was the side closest to the CPU. I retested it also with the power off and then pressed on, and got .25v for just a split second before heading to a stable 1.79v. I'm assuming this is a good working voltage for the inductor... These tests were done with only the battery as the power source, no external charger plugged in.

          Hate to be a such a lemming(tho an excited one), but what do I do next? You know your stuff man, thanks! This is exciting to be helped by someone so knowledgeable in a topic I know so little about, hope there is still hope for this mobo to start working again.

          Comment

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