Hello,
I try to learn laptop repair myself. I have some basic experience.
Laptop is Dell E5550 LA-A911P R.1 ZAM80.
Laptop switch on just for a 1-2 seconds and switch off. No self-restarts.
I can switch on agin, but situation repeat.
PL101 3.3V
PL102 5V
PL700 19.08V
PL701 13.60V
On rest coils 0V jumping up just for a while when i push power button.
I found near pin 4 of PQ200 something like side-melted housing. I found that there is a short between pin 4 and 5 of this chip.
My plan for tomorrow is to unsolder PQ200 and check also PQ201, because now it also show low resistance.
How to check if PU200 also need replace and maybe it is no-brainer when PQ200 is faulty, then PU200 also?
Maybe replace some small resistors/capacitors in it's area also, as i see there is PWR_SRC, so 20V on this line and can go straight on leg PU200?
Plan for tomorrow also:
I found some hint to check Measure voltages on pin 2, 4, 7, 8, 11, 12, 13, 18 of PU200 but don't know what values will be proper one?
2- shall be 0,67V?
4- VDDR ref. As DDR is 1,35V, so there shall be that voltage?
7- 0,675V_DDR_VTT - but DDR is 1,35V, so what i shall get here?
8- _1.35V marked on line
11-5V
12- 5V
13- 1,35V
18 -1,35V
Thank you for hints.
I try to learn laptop repair myself. I have some basic experience.
Laptop is Dell E5550 LA-A911P R.1 ZAM80.
Laptop switch on just for a 1-2 seconds and switch off. No self-restarts.
I can switch on agin, but situation repeat.
PL101 3.3V
PL102 5V
PL700 19.08V
PL701 13.60V
On rest coils 0V jumping up just for a while when i push power button.
I found near pin 4 of PQ200 something like side-melted housing. I found that there is a short between pin 4 and 5 of this chip.
My plan for tomorrow is to unsolder PQ200 and check also PQ201, because now it also show low resistance.
How to check if PU200 also need replace and maybe it is no-brainer when PQ200 is faulty, then PU200 also?
Maybe replace some small resistors/capacitors in it's area also, as i see there is PWR_SRC, so 20V on this line and can go straight on leg PU200?
Plan for tomorrow also:

I found some hint to check Measure voltages on pin 2, 4, 7, 8, 11, 12, 13, 18 of PU200 but don't know what values will be proper one?
2- shall be 0,67V?
4- VDDR ref. As DDR is 1,35V, so there shall be that voltage?
7- 0,675V_DDR_VTT - but DDR is 1,35V, so what i shall get here?
8- _1.35V marked on line
11-5V
12- 5V
13- 1,35V
18 -1,35V
Thank you for hints.
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