Asus P552W Manual page 20

B. VCC_BBAT= 2.9V
If VCC_BBAT is < 2.9V, please examine chip U901 and the
resistors/capacitors around it. Observe if there is any defect.
C. nBATT_FAULT(R321) = 2.9V
If incorrect voltage is observed, please examine any possible
defect on U303, U304, U305, U306 and the surrounding components.
D. 32KHz clock (TXTAL_IN)
If 32KHz clock signal is not measured, please examine any
possible defect on X301 and the surrounding components.
E. SYS_EN(U406.1) = 2.9V
SYS_EN is the signal that sends from the CPU to the PMU to
indicate power on sequence is running correctly up to this point, and
can continue to turn on certain power domains.
If SYS_EN voltage level is incorrect, it is likely there is a defect on
the CPU (U301)
F. VCC_MVT(R515)=1.8V；VBUCK3(C943.1)=2.1V；
VCC_MVT_PLL_CORE(R525)=1.8V；
VCC_MVT_CLK(R528)=1.8V；LDO2(R927)=1.8V；
LDO3(R931)=2.8V
If incorrect voltage is measured on the above power domains,
please check if there is any defect on U901, L903,
U301,U41 ,L8 ,L9 ,L10 and the surrounding components.
G. PWR_EN (U304.2)= 2.9V
PWR_EN is a signal that sends from the CPU to the PMU to
indicate that power on sequence is running correctly upon this point,
and the PMU can proceed to turn on the remaining power domain
required for the CPU. If all the power domains measured in
procedure 1-E are correct, but PWR_EN is measured at an incorrect
level, then it is most likely that there is a defect on U901 or U301.
H. Verify if V_COMM(R966) and V_APPS(R967) voltage level are
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GTC ■ Service Manual
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