Asus x55a no power or bootup

[brew99]

Re: Asus x55a no power or bootup

OK, so you are not getting any 5 or 3V SMPS, but are getting the 5VLDO. You have the Vin and EN1 logic high for the 5V o/p. Have you measured the 4 FETs (upper/lower) for shorts? Have you tried supplying power using a benchtop power supply to see any shorts on the B+ rail? Otherwise, I would possibly change the chip.

Hopefully someone else will jump in and give you a better analyses as I'm kinda still "green" in this whole thing.

[on/off]

Re: Asus x55a no power or bootup

As piernov said on post#10 no worry about B+ (on Asus platform called AC_BAT_SYS).

Seem SMPS on PU8100 present after pressing power button, make sure 3VA_EC should present. if not then, Ensure you should have no shorted to ground on 3VAO - 3VA - 3VA_EC - 5VO -3VO rails.

Also need to check LDO IC that provide supply for EC, it should be PU8101

Read datasheet to know where the input voltage, Chip enable voltage and Output voltage.

[garrymc123]

Re: Asus x55a no power or bootup

Cheers guys for this information but i can't find on any of those chips with 3VA_EC pin i can find 3VA_EN on PU8101 but not EC .So when i do find it i've to check if the 3v appears after i press the power button is this correct

[on/off]

Re: Asus x55a no power or bootup

Cheers guys for this information but i can't find on any of those chips with 3VA_EC pin i can find 3VA_EN on PU8101 but not EC .So when i do find it i've to check if the 3v appears after i press the power button is this correct

Measure Voltage on PU8101

[garrymc123]

Re: Asus x55a no power or bootup

Hi On/Off The voltage for PU8101 is

pin 1 P_+3VA_EN_10 4.954v
pin 2 gnd
pin 3 +5VA 4.999v
pin 4 +3VAO 0.793v
pin 5 P_+3VA_FB_10 3.297v

Thanks

[on/off]

Re: Asus x55a no power or bootup

How many resistance on PSL8112?

[garrymc123]

Re: Asus x55a no power or bootup

its 28.82 multimeter in ohms black probe on ground next to it

[on/off]

Re: Asus x55a no power or bootup

I would prefer classic way by clean JP3001 with solder wick or braids, when the gap was clear, measure again on PSL8112, hope resistance going high. therefore we know probably EC/KBC chips that was causing low resistance. There big chance EC/KBC was the culprit.

[Kiop]

Re: Asus x55a no power or bootup

What is EC / KBC :

https://support.toshiba.com/support/...ntentId=321020

Is it still correct 16 years after ?

[on/off]

Re: Asus x55a no power or bootup

Yes. On post#28 I mention the EC/KBC chips itself, Not Firmware. Sometimes other techs said SIO chips (Super I/O)

[garrymc123]

Re: Asus x55a no power or bootup

its 32.34 with JP3001 open

[Kiop]

Re: Asus x55a no power or bootup

Yes. On post#28 I mention the EC/KBC chips itself, Not Firmware. Sometimes other techs said SIO chips (Super I/O)

Like ITE chip or other like Ene ?

[on/off]

Re: Asus x55a no power or bootup

its 32.34 with JP3001 open

Hmm, It's out my expectation. Maybe the resistance was opposite what i was thinking. on those line (+3VA_EC, +3VA, +3VAO should be range kilo ohm value or voltage drop when diode mode (0.4V). JP3001 already open, could be +3VA_EC have high resistance, but on +3VA/+3VAO low resistance. If like that probably PU8101_EM1101J (equivalent UP7714BMA5) was bad.

Like ITE chip or other like Ene ?

In this case it's definitely IT8517E/HX chip.

[garrymc123]

Re: Asus x55a no power or bootup

ok so how do i go about changing the super io chip

[risting]

Re: Asus x55a no power or bootup

i replace mosfet A5 GNC 100M01 with M0930M
and laptop again working but automatic go to bios no booting windows restart i will try to format and install new windows or motherboard again have some problem on board one mosfet CDJ0961 near to processor give me short to ground i don't know it is this correct inductor and smd capcitors on multimeter give me shorted i need help is this correct motherboard to be shorted on this point ? can i replace cdj0961 with m0930m mosfet too ?

Datasheet:
Drain-Source VoltageVDS 30
Gate-Source VoltageVGS ±20






video here ; https://www.youtube.com/watch?v=UeEzg2hw8ZM

[risting]

Re: Asus x55a no power or bootup

i fixed this laptop dead mosfet A5 GNC 100M01 and dead hdd drive after replace mosfet and new hdd laptop working well