Can bad eDP cable cause boot issues ? (N857HK1)

Discussion in 'Sager and Clevo' started by ugurkrl, Oct 20, 2021.

  1. ugurkrl

    ugurkrl Newbie

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    hello. I have Clevo N857HK1 (reseller name is Monster)
    I had some issues with display (random vertical lines when i change angle of lid). Somehow i fixed it with loosening cable from hinge a little.
    But now i have different issue. When i use notebook, there is no issue (even when using in intensive gaming, intensive loads, no bsod etc.). But when i power off or put it to sleep and trying to wake after 5 or 6 hours it fails to boot or cant wake from sleep. But if i try to wake or power on immediately after put to sleep it can boot.
    When i press on power button , fans working normally, kb light working normally and FN+1 works too(so i guess EC is ok?) but no HDD led and display does not come (no LCD backlight either). Sometimes fans go maximum and power led blinks and shuts. After 5-6 mins of continious trying i can manage to boot. Then there is no issue after boot. Sometimes it starts to boot and hangs on bios logo.

    Things i tried :
    downgrading bios
    disabling dgpu and intel turbo (used amibcp to mod bios)
    checking rams
    tried to boot without battery ( suspected of bad SMBUS lines ?)
    tried to boot without disks
    tried different keyboard
    reseated fan cables
    tried different intel MEI versions
    changed CMOS battery ( i thought maybe low battery corrupts nvram and it messes boot process but i was wrong)

    Also there is no burn or any damage marks on motherboard. Since its working after boot, i think there is no gpu or cpu solder issues. And i never play heavy games and temps barely exceeded 70C' in its lifetime so it cant be solder joint issue.
    For last few days that issue is gone but screen issues came back. So is it possible to broken eDP cable interrupts boot process ? Should i try to change cable it or just get rid of the PC ? Also there was TURBO issue on last version of bios. When turbo was enabled, system was hanging when there was no load but downgrading bios fixed that issue . Current bios version is 1.05.13
    I cant send pc to reseller because our resellers technical service reputation is extremely bad. (eg. sending pc for cleaning and it returns with broken keyboard or broken screen etc.) I'm Electronical Engineer so if i can figure out where is problem i can solve.
    Thanks.
     
  2. Tech Junky

    Tech Junky Notebook Deity

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    DCH drivers seem to cause the black screen issue. Try different version and see if it's resolved.

    For the multiple boot attempts it might be a RAM stick that went bad.

    EDP cable swap is a $15 change you can try in as little as 15 minutes. Conceivably could cause a boot issue if it's shorting out on POST and causing a shutdown.
     
  3. Meaker@Sager

    Meaker@Sager Company Representative

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    I agree I am suspicious of ram, try each stick in each slot.
     
  4. ugurkrl

    ugurkrl Newbie

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    I already tried different rams, different combinations. No luck.
    Hardest part is issue only happens after long time when i shut down computer. Repair process goes like : "oh i fixed it this time i can go to bed" then it does not boot next morning.
    My first suspicion was bad solder joints but everything works flawless when i do stress test. Even with physicial stress test (slightly shaking or slightly bending housing) it does not fail.
    Sometimes i managed to boot while opening or closing lid so my main suspicion is eDP cable but it could be coincidence too. I repaired so many laptops of my friends and family but this is weirdest issue i saw so far.

    I noticed that when it does not boot sometimes power led blinks 30-40 times orange and fans run at maximum speed then it shut downs. What does that led sequence means ?

    Also eDP cable might be cheap but i have to make sure cable is the problem. First thing is economics in our country is pretty bad and cable is around 35USD in our country (hourly wage is 1.5USD so i have to work 24Hours for a stupid but important cable). Our reseller refuses to sell spare parts. Parts in china/taobao is cheap but i have to wait 1.5 months
     
    Last edited: Oct 20, 2021
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