asus k54c board dead no power on but it power on with out cmos

[skbasir]

case--- asus k54c not power on when press power switch

but power on without rtc batty

[hidden]board ----- k54c main board
diagnosis
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checked with other cmos battery same issue

checked in switch have 3.3v

when remove cmos laptop power on when put adapter

but when power on if press switch long time laptop goes shutdown but again press no power on

this model have no schematics so it is difficult to find the solution

this board have sio ITE IT8572E SO ITS PIN 122 IS FOR DNBSWON SWITCH

CHECK THIS PIN ALSO 3.3V WHEN PRESS SWITCH ALSO CHECK VOLTAGE DOWN TO ZERO

AFTER LONG SEARCH FOUND 10K OHM RESISTER VALUE DOWN TO 9K OHM

IN PANEL SWITCH HAVE NO ALL 3.3V SHOWN N PICTURE EXCPET POWER SWITCH VOLTAGE

ALL VOLTAGE SHOWN IN SWITCH PANEL PICTURE SHOULD BE THERE BEFORE POWER SWITCH EXCEPT 5V



RESOLUTION

JUST REPLACE THIS RESISTOR WITH 10K OHM AS IN PICTURE AND LAPTOP POWER ON WITH SWITCH

AFTER REPLACE RESISTOR ALL VOLTAGE 3.3 FOUND IN SWITCH PANEL IN IDEAL CONDITION MEANS BEFORE PRESS POWER SWITCH

THIS JOB DONE WITHOUT SCHEMATICS SO THAT CANT MENTION OTHER THING ABOUT THIS RESISTORS[/hidden]

[javed]

very very nice sir

[karmina]

good job sir thanks for sharing

[PINTUSINGH]

THANKS for shairing

[anandvsalunke]

Hi,

Sometimes you need to work without schematics. Let's understand your case.

The RTC battery provides power to RTC (real time clock) area either in EC or in chipset. It also supplies reset to the respective area. If there are such issues, I normally check for unusal drain on RTC battery. It's a small lithium ion battery that does like even few milliamp load and if it drains too quickly in 10 mins or so, the fault is likely with short/leaky ceramic cap in RTC supply or reset line.

Pl check RTC battery abnormal drain before sending machine back to customer.
All the best. keep learning..

[ Post made via Android ]

[skbasir]

Hi,

Sometimes you need to work without schematics. Let's understand your case.

The RTC battery provides power to RTC (real time clock) area either in EC or in chipset. It also supplies reset to the respective area. If there are such issues, I normally check for unusal drain on RTC battery. It's a small lithium ion battery that does like even few milliamp load and if it drains too quickly in 10 mins or so, the fault is likely with short/leaky ceramic cap in RTC supply or reset line.

Pl check RTC battery abnormal drain before sending machine back to customer.
All the best. keep learning..

[ Post made via Android ]

yes sir i am alradey checked cmos ok

but after long discussion in whatsapp group as per rajeev dhiman sir it is issue in lid_sw issue

so once again i checked it lid_sw issue found

but here i am not update .....


thank you sir

[anandvsalunke]

Thanks for updating. I had similar issue with Lenovo once. The board doesnt boot up thinking that the lid switch is activated.