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華
碩
電
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華
碩
電
腦
GTC ■ Service Manual
b. Execute GPSinformation_en debug tool and press "Start GPS"
showed on the debug tool. The usage of debug tool and its related
parameters are prescribed in the appendix.
c. Use an oscilloscope to measure frequencies oscillated by TCXO
(OSC2001) and RTC (X2001). The frequencies may not be
measured precisely due to measurement error, but should
approximate typical values in the following table. TCXO
(OSC2001) or RTC (X2001) need to be replaced if no proper
clock is measured on corresponding test point.
d. Use a multimeter to check output voltage level from LDO
(U2010), power switch (U2008), and four voltage regulators of
U2001. LDO (U2010), power switch (U2008) or U2001 need to
be replaced if no proper voltage level is measured on
corresponding test points. The following table shows component's
location number, DC test point, and typical voltage level.
e. Use an oscilloscope to probe R2021 for checking GPS on/off
trigger mechanism. A pulse signal is triggered from GPS chip
(U2001) as pressing "Start GPS" and "Close GPS" repeatedly in
the debug tool. In addition, voltage level on R2023 changes when
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Troubleshooting
