hello,
i need some advise before plug this crapy thing on AC
it is a all in one lenovo laptop, ideacentre with a la-d831p motherboard.
this one come with no power , no led, dead state.
open it and see that 12V power rail that goes to CPU power supply was totaly fried, and the two coils on it was blown. so remove this coils, but some solder mask on the rail and replace for test by 2 0ohm resistor (can't find the reference of PL smd)
with this problem, one mosfet going to cpu was shorted : sm4377 on PQ1001 location. without this one no other short between pre and post mosfets.
cpu seems to be fried too, so i had changed with another one. after press power button, the fan is spinning but no image on screen. just switch off
the 2 0ohm resistors are blown and the mosfet i had replaced blown too (as the first time)
remove this fet, replace and now no short mosfets.
i replace àohm resistor by 22ohm resistor.
now, when i mesure in diode mode, got 500 on the 12V side of the fet, and only 450 on cpu side without cpu
when i put cpu, got only 0.9 and this raise nearby 3.
if i push power button without cpu, span is spinning and got 12V on 12V side of all fets going to cpu.
but i will not try with cpu without your advice.
what do you think about this ?
thank you
i need some advise before plug this crapy thing on AC
it is a all in one lenovo laptop, ideacentre with a la-d831p motherboard.
this one come with no power , no led, dead state.
open it and see that 12V power rail that goes to CPU power supply was totaly fried, and the two coils on it was blown. so remove this coils, but some solder mask on the rail and replace for test by 2 0ohm resistor (can't find the reference of PL smd)
with this problem, one mosfet going to cpu was shorted : sm4377 on PQ1001 location. without this one no other short between pre and post mosfets.
cpu seems to be fried too, so i had changed with another one. after press power button, the fan is spinning but no image on screen. just switch off
the 2 0ohm resistors are blown and the mosfet i had replaced blown too (as the first time)
remove this fet, replace and now no short mosfets.
i replace àohm resistor by 22ohm resistor.
now, when i mesure in diode mode, got 500 on the 12V side of the fet, and only 450 on cpu side without cpu
when i put cpu, got only 0.9 and this raise nearby 3.
if i push power button without cpu, span is spinning and got 12V on 12V side of all fets going to cpu.
but i will not try with cpu without your advice.
what do you think about this ?
thank you
