lenovos t440s ACID vs reality

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  • reassor
    Senior Member
    • Apr 2021
    • 176
    • Poland

    #1

    lenovos t440s ACID vs reality

    So i have this bullcrap lenovo t440s it had "blocked it self" so we disconected secondary bat + bios bat and it arose

    problem was 2 weeks later it was back with dead SMSC MEC

    we bought used working board gave it assembled back.

    2 weeks later they come back that its not working right.

    DESCRIPTION OF THE PROBLEM:
    i7 t440s should charge of 45w charger (got them in buckets )
    what it does is power button starts to blink and until you close the lid (only after first run) it catches on.

    Service PSU with 0.5k (90W) cable works just plug in 3 blinks - charging.
    You take that same cable to a charger - lets say lenovo but asus like plug and switch cables - NOPE it will just keep blinking like its negotiating peace treaty.

    After measuring voltages on like a dozens of chargers between ACID and gnd - used multimeter with capture max - it was all ok and within specs.
    Im like wtf - lets see the current tried with a 300w brick we have wich works w/o amp meter in line. but with it it just stucks at 0.85amps

    Can some 1 explain to me what happens after the initial pulse for ACID? is it probed for current?

    Or is that SMSC MEC just sillly too?

    I actually gave this cliean genuine 90w charger just to get rid of him.
    But its not a sollution.

    COul not measure deep into the board it self since its all covoered with this black foil thing and when we bought it we got 1y warranty which we will use before it runs out- was just curious if any of you are familiar with how this shit rerally works?

    or is it just simple data line corruption and strong charger like 90w can push thru? then why cannoy silly charger with 90w cable do the same?

    it was bugging me whole week ;p

    though i will ask;p is there some behind the scenes talking going on with amps or probing?

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