FLY E185
Service Manual
CKT Confidential
Page 33 of 47
Figure 3.4.11-2 G sensor
Chapter 4: Failure Analysis
Actually, the handset’s main failure cases are:
z
Power on problem (No power on, Auto-Power on/off, Phone totally dead, Restart
automatically)
z
Display problem (No display, LCD backlight malfunction, Segments missing, Black display,
and Contrast malfunction)
z
Signal problem (No signal, Weak signal, No signal intermittent)
z
Charging problem (No charging)
z
Keypad problem (Keypad fault, Keypad disorder)
z
Call problem (Drop calls, No incoming audio, No outgoing audio, Can not receive call, Can
not dial out, Bad voice quality, and Low receiving volume)
z
Other Function problem (Can not Config, No ringing tone, No vibration, Vibrator abnormity,
Clock fault, Can not read SIM /T-F card, Phone password locked, Can not upgrade software,
Show "high temperature", FM Radio fault)
In the mobile circuit system, all the electrical connecting trace can be divided into three types,
such as power supply trace, controlling trace and signal trace. When analyzing the RF failure case,
for the active circuit we should first check the power supply, then control circuit followed by the
signal flow path to remove the failure step by step. When debugging the RF malfunction, we
