Hi everybody
My ASUS PD551LA (REV 2.0), after a week powered off with power adapter disconnected, is not booting anymore.
If I plug the adapter, the battery is charging, the power led lights but after pressing the power button there is no sign of life.
I've found the Boardview file of the motherboard and the schematic of PU551JA (that looks 99% compatible).
I've disconnected the battery and all devices except screen (I removed also the RTC battery, hope it's not a problem at this stage...) and checked all signals and power rails involved in the power on sequence:
All signals up to PM_SYSPWROK and BUF_PLT_RST# seems good (they rise to 3.3V when I plug the adapter in or after I press the power button), but the display doesn't light and there are no beeps. The cooling fan sometimes starts (for a while) and sometimes not…
Since the boot process arrives at this step, I suppose EC and PCH are good, am I right?
Do you have any suggestion on what should I check next? Don't tell me the CPU has gone…
Should I expect to see sign of life on the bios flash chip after the BUF_PLT_RST# has gone high?
What clock is usually used to read it (just to know if my low cost oscilloscope should be able to see it)?
Thanks for your help
My ASUS PD551LA (REV 2.0), after a week powered off with power adapter disconnected, is not booting anymore.
If I plug the adapter, the battery is charging, the power led lights but after pressing the power button there is no sign of life.
I've found the Boardview file of the motherboard and the schematic of PU551JA (that looks 99% compatible).
I've disconnected the battery and all devices except screen (I removed also the RTC battery, hope it's not a problem at this stage...) and checked all signals and power rails involved in the power on sequence:
All signals up to PM_SYSPWROK and BUF_PLT_RST# seems good (they rise to 3.3V when I plug the adapter in or after I press the power button), but the display doesn't light and there are no beeps. The cooling fan sometimes starts (for a while) and sometimes not…
Since the boot process arrives at this step, I suppose EC and PCH are good, am I right?
Do you have any suggestion on what should I check next? Don't tell me the CPU has gone…
Should I expect to see sign of life on the bios flash chip after the BUF_PLT_RST# has gone high?
What clock is usually used to read it (just to know if my low cost oscilloscope should be able to see it)?
Thanks for your help
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