Announcement

Collapse
No announcement yet.

Hp Elitebook 820 g3 do not turn on /Please help/

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Hp Elitebook 820 g3 do not turn on /Please help/

    Hello Forum Members!

    I have a Hp Elitebook 820 g3 ( mb: 6050a2892301-mb-a01).

    The seller forgot to tell me it has a bios admin password set. LAter he could not remember... I found this forum and i planned i will do it myself with a ch341ai just purchased. Unfortunatelly laptop has a wson8 chip (no legs), a winbond 25q128fvpq bios chip.


    Because i had no hot gun to take out wson8 chip, i used my cheap soldering iron and tried to solder wires around the bios chip, because it has copper/gold pads around the bios chip to use (these pads to replace wson8 to sop8 if you want, i think). So when i was almost ready i realized that a small resistor (if true it is 3.3k 5% thick film resistor) what was very close to bios chip somehow i made it dissapear with my extra hot soldering iron. Also three of the factory installed copper/gold pads peeled off/came off by my extra hot soldeing iron and of course my noob hands... ( At this point i stopped everything and gave up. OF course laptop not turn on anymore.

    Symptom: As soon as i plug the charger in, or i attach the battery, at the same time immediately the power button's white led above the keyboard start lightening and slowly blinking (cca every 3 seconds one blink), and the other two leds (white color and orange yellow color) on the front edge of laptop start keep rapidly blinking (the yellow colored led fast blinking) and the other white led next to it is keep continuosly Lighting.

    I found a local guy, who is pro, he installed a 3.3k resistor from an other laptop, he also patched my broke copper/gold pads, he used very thin copper wire to bridge the paths, he already desoldered and resoldered bios chip many times, we used three different bios dump and uploaded it (many thanks it to Peste) but no luck, not tunr on, no change in behavior.

    Before it was good, only bios password i wanted to remove.

    What is interesting the laptop do the same sympthom, doesen't matter if bios chip is soldered back into its place or out of laptop, i mean as soon as i put charger or battery the leds starting lighting/blinking as i write above, doesen't matter if bios chip in its place or outside of laptop! The bios chip can be detected / read / write / erase/ verify anytime by programmers (asprog,nero,ch341), always same content. So we think bios chip is good, but not sure...

    We checked voltages, what is looks bad is that at leg PIN 1 of bios chip, the voltages keep dropping between 2.95 - 3.33 volts. ?!

    Also if no charger or battery (main) attached to laptop, we can measure only 0 volt (zero volt) on bios chip's any leg... :o But the 3 volts RTC cell battery we think should feed it with 3 volts alone, right?

    Do you have guys any idea what went wrong? What to check?

    Thank you so much.

    Regards,
    Tomcsa

    #2
    Re: Hp Elitebook 820 g3 do not turn on /Please help/

    Additional info:

    At power button switch only 2.1 volts measured (maybe 3.3 volts should be here?)

    At EC bios pin 1 there is big continuos voltage drops too (from 0.5 - 3.3 volts), like at main bios pin 1 (2.85 - 3.33 volt), as i think those values at pin 1 should be 3.3 fix, right?

    Any idea please?
    Last edited by Tomcsa; 01-04-2021, 04:32 PM.

    Comment


      #3
      Re: Hp Elitebook 820 g3 do not turn on /Please help/

      Seems problem in 3.3v ic

      Power button should have 3.3 voltage before pressing

      Remove power button and check at connector

      Comment


        #4
        Re: Hp Elitebook 820 g3 do not turn on /Please help/

        Originally posted by stingerchamp View Post
        Seems problem in 3.3v ic

        Power button should have 3.3 voltage before pressing

        Remove power button and check at connector
        Hello,

        thanks for the info. right now it is 2.3 volt, if i press it it goes down to 0. I will remove power button and see connector.

        Also what you think why is my both bios (ec+main) has at pin 1 those voltage drops continuosly ? At pin 8 it is stabile 3,3 volts.

        Does those small thick film resistors around bios chip can make problem like this voltage drops?

        Thanks

        Comment


          #5
          Re: Hp Elitebook 820 g3 do not turn on /Please help/

          Bios ic pins 1,2,5,6
          These are signals, frequency signals

          Voltage will not be stable or need oscilloscope to check frequency or data signals


          Remember To operate any synchronization ic we need three things in general

          Power supply
          Clock
          Signal en

          Comment

          Working...
          X