Asus P552W, Manual, Page: 21 / 117

GTC
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Service Manual
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華
華
碩
碩
電
電
腦
腦
in the range of 0.9~1.4V.
If not, please examine if there is any defect on U901, U301 or the
passive components on this two power domains.
I. 26MHZ clock (26MHZ_SYS )
If 26MHz clock is not measured, please examine if there is any
defect on OSC1801,C1802, U1802 and the surrounding components.
Figure 1.1. nBATT_FAULT Circuit
If all the voltage measurement performed in procedure 1 are all
normal, but the device is still unable to power up, it is advise to use
the oscilloscope to measure R433(OneNAND_nCS) and observe if
there is any high-low transition; If not, it is likely there is a defect on
U601 or U301; If high-low transition on R433 can be observed,
please measured TP610(SD0) and verify if it also have high-low
transition. If not, it is likely that there is a defect on U605.
2.2.2 RTC can’t power on issue
Please check the following point, if it is all matched ,it’s defined
as a can’t-power-on issue
A. Measure the system current with power supply, it must be around
0mA.
B. Short push power button, system current is still not up.
C. Long push power button, system current is still not up.
D. HW reset(push the power button and reset key at the same