Dell 5160 laptop won't POST

By Ruu
Apr 3, 2008
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  1. Hi all,

    The 5160 is about 4 years old (says the owner, who is not me). Owner complained of slow boot times, system hanging at shutdown, and general unresponsiveness. The system is running XP Home and just had a memory upgrade (to 1 GB). The system was stable after the memory upgrade but still sluggish---there was nothing running in the background, either, and about three things showing in the system tray.

    Owner handed the laptop over to me because it was starting to suddenly shut down in the middle of non-intensive tasks---email, word processing---and would refuse to boot again. I noticed that the fan spun constantly and loudly and offered to take the laptop apart to do some cleaning. There were gobs of nasty black dust bunnies choking up the heatsink. I stripped the whole thing apart down to the motherboard, cleaned up everything, and put it all back together.

    The problem now is that the laptop refuses to POST. The power LED lights up when the power button is pressed (but not the harddrive LED right next to it), the fan spins up, the harddrive spins up, and then everything shuts down after about 2 seconds of a black screen. No flicker to indicate that electrical current even got to the screen. The first four or five times it happened, I watched the NUM/CAPS/SCROLL lights, and the caps light blinked steadily until the laptop shut down again---so I figured it was a motherboard problem (per Dell laptops' error blink codes). Took the whole thing apart again, checked to make sure everything was seated, checked to make sure nothing was jammed into a space it shouldn't be jammed into, and put it all back together again. Now the laptop does the same thing, only NONE of the NUM/CAPS/SCROLL lights come on. Not quite sure what that means.

    Any thoughts? I thought to pop out the CMOS battery but can't find it and can't find anything that even looks like it could be a battery---is it soldered to the mobo in this model? Have I perhaps fatally shorted something in the mobo? Owner also mentioned that the laptop was at the point where it couldn't run on battery alone---the laptop had to be plugged in---and since the laptop had been in pieces on the floor for about four days, I'm wondering if I should let it sit and charge before trying to boot it again? The battery charge light is blinking, so I know that SOMETHING in there is working.

    My suspicion is that it's a hardware problem, and that it's an electrical hardware problem (something is getting too much voltage, something has shorted, something isn't getting power) as opposed to a mechanical hardware problem (some component is broken, some component is unseated). I say this because it worked fine before I took it apart, and now it doesn't even boot. If so, I'm wondering how to confirm my diagnosis.

    Bit anxious about the whole situation, really. Any input would be really appreciated. Thanks in advance!

    ~ Ruu
  2. Matthew

    Matthew TechSpot Staff Posts: 6,043   +84 Staff Member

    Is it possible that something has been damaged via ESD? Maybe something is grounding the motherboard?
  3. woody1191

    woody1191 Newcomer, in training Posts: 638

    By you saying that I'm assuming that your HDD may have spun for the last time (Dead). Check the HDD is connected properly otherwise looks like you need a new HDD

    Also the battery problem you mention you would have to re-calibrate your battery through the BIOS.
  4. Ruu

    Ruu Newcomer, in training Topic Starter Posts: 25

    Zenosincks - Hello again! Yes, it's very possible that something might have been fried because of ESD, and that's what I'm trying to confirm (or rule out). However, I have no idea how to go about it. I haven't got a multimeter or any special equipment, and I don't even know if special equipment would help in diagnosing the problem. Is there any such list of "common" mobo shorts and problems? It's also very possible that the mobo is somehow grounded, but again---I'm not sure how to determine this. Advice?

    woody1191 - Thanks for the reply. As far as I can tell, the hard drive spins up when power is first introduced to the system---correct me if I'm wrong, but it's been my experience that during the first few moments that is system is turned on, the CPU fans, PSU fans, GPU fans, and hard drive(s) all spin up rapidly but briefly (say, a second or two). Then when the computer goes into POST, all the fans and the hard drive(s) spin down again. So I know that the laptop harddrive is mechanically functional because I can hear it spin up when it's first powered. The drive is definitely connected and not loose, and while it's possible that the drive is faulty, I suspect that it's not the primary problem (mainly because it was working fine before disassembly, and I haven't dropped it or damaged it in any way since).

    As far as recalibrating the battery goes, I can't get into my BIOS because the system can't power up that far. By listening to the fan and harddrive sounds, my very uneducated guess would be that power isn't even getting to the BIOS chip. :(

    I found a thread on here about deliberately shorting the EEPROM to reset things---sounds like a bad idea, but I'm willing to try it (provided I can even find the chip). However, my first suspicion---that there is a short somewhere---still holds. Sigh. What do others think?
  5. Matthew

    Matthew TechSpot Staff Posts: 6,043   +84 Staff Member

    ESD is essentially a silent killer unless you feel the jolt between yourself and the component. It's rare, but it happens and it wouldn't be surprising if it did with the laptop disassembled on a floor for 4 days :). I'm not sure how to go about testing for ESD apart from replacing a component, which, isn't a realistic situation with a laptop considering the fact that virtually everything is integrated.

    As far as something grounding your motherboard goes, it could be as obvious as a loose screw wedged between your motherboard and the case/tray, and it might be a well hidden piece of metal barely even touching your motherboard. Not really sure how you can "test" for this per-say, really, all you can do is eliminate the possibility that it's occurring.

    :) Not saying that I'm positive either of them are definite candidates, but, they're possible.

    Oh, and hello Ruu :D!
  6. Ruu

    Ruu Newcomer, in training Topic Starter Posts: 25

    Just took the whole thing apart again---nope, no loose screws, and no hanging metal bits. Everything tucks into where it's supposed to, and very neatly, too. Hmm. So now I'm just looking at a static short, which is... quite unfortunate. And yeah, probably shouldn't leave sensitive electrical hardware on the floor, but at least it wasn't carpeted floor. :eek:

    Had a thought, though, and wanted some feedback---will a system with an unseated processor chip still POST? The reason I ask is that the CPU heatsink for this Dell is firmly, firmly, FIRMLY stuck to the chip itself, pretty much cemented. The thermal paste has become a solid mass, and when I took the heatsink off to clean it, the chip popped right out of the socket. I ended up sticking the chip back into the socket with the heatsink attached, and now I'm wondering if I've seated it correctly. Could this be causing the lack of a POST sequence? How sensitive are CPUs to alignment and jostling? How can I be sure I've seated the chip properly?
  7. Matthew

    Matthew TechSpot Staff Posts: 6,043   +84 Staff Member

    That, Ruu, is probably a significantly more likely cause than ESD. No, your system will not POST without the CPU being seated and fully operational.
  8. lamo

    lamo Newcomer, in training Posts: 570

    Ruu, you'll have no luck with this model, because this compal board has too many development errors(cpu socket located too near to northbridge, too hot system of mosfets of CPU current, constant problems with KBC controller and southbridge). sometimes, you can just put out the CPU for thermal interface renewing pull it back and laptop won't turn on, due to corruption of soldering of CPU socket.
  9. sangy

    sangy Newcomer, in training

    Resolved !!

    I also faced same Issue .. See how it can be resolved

    1. Disable Speedstep & Hyperthreading in BIOS ( It's CPU setting on 5th or 6th page of BIOS Setup.

    2 If you can't enter into BIOS then HOLD the Power cord firmly and push it harder when you hit Power button.. you should be able to enter into BIOS Setup..

    I am not sure how much CPU performance would be impacted but at least you will not face this nasty issue..

    Cheers
    Sangy
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