Asus K54LY rev 2.1 - no post

[sicilianul]

Hello

I have this laptop, which came with dc jack broken, and after repair it didn't post anything.
So there it goes - searched schematic and power seq. Untill now what I discovered is PIN 29 from ITE8572E that hasn't any signal or voltage. Rest of them are ok, 3.3v, attached a photo for better understanding.

Do you think is ITE damaged ? Or ME region has problems ?

Tried 2 cpu's, memory, bioses, all voltages are present on the board.

Any ideas ?

[caspian]

Re: Asus K54LY rev 2.1 - no post

the 29 written beside PM_SYSPWROK is not pin number in the photo. it is just a sequence number. you can find the pin number if you find the boardview or the repair-guide of this laptop.

[kiraro]

Re: Asus K54LY rev 2.1 - no post

try to trace PM_SYSPWROK via RN2206 (10k). here is a boardview.

[sicilianul]

Re: Asus K54LY rev 2.1 - no post

theoretically PIN29 from IO should go directly to RN2206.

But no, reading your boardview - Pin85 goes to RN2206. And this heapens in reality with my motherboard.

So my schematic is wrong or what ?

[kiraro]

Re: Asus K54LY rev 2.1 - no post

29 it's the order number in power sequence (like we say step n°29) of the PDF repair guide, not pin number of the kbc , the boardview is correct, so if no voltage trace step 28 before "CORE_PWRGD"....

[sicilianul]

Re: Asus K54LY rev 2.1 - no post

I reviewed all traces from power seq, and thanks Kiraro and caspian for observation.

Now i've discovered that first 12 steps are ok. I don't understand why is 13 step with red.
It's missing from boardview and step 14 PM_SUSC# is present for a second and then is zero. And it's doing this every 4 seconds. Is this normal?

[sicilianul]

Re: Asus K54LY rev 2.1 - no post

Anyone any help ? Any ideas ? I declare it garbage ?!

[piernov]

Re: Asus K54LY rev 2.1 - no post

If you have an issue starting from SUSC# you cannot have all voltages present. Check again voltage on all inductors to see which ones have steady voltage, which ones pulse and which ones have no voltage at all.

I assume you are testing the motherboard our of the chassis with known good AC adapter with correct power rating, power button board to turn on the board, CPU, RAM, and nothing else.
You can also try without CPU or RAM or power button board (shorting pin to ground for the power button on the connector on the motherboard instead) to exclude any of these component being shorted for some reason.