FLY FS501, Руководство по обслуживанию, Страница: 15 / 29

FLY SERVICE SUPPORT
WIFI BT share RF access, signal is entered by antenna, through U808 2.4GHZ filter, filter sideband unwanted
signal. The clock uses 26M clock provided separately. Data transfer interface and audio interface are directly
connected to the CPU. Interface has SDIO is used for the WIFI signal transmission; PCM is used for the BT signal
transmission.
WIFI main problems
：
1. SR2351C chip has been calibrated before out of factory, production line directly do FT test. The probability that it
appears problems by WiFi test is very low, the FT failure problems, please power off and restart the phone, first
retest.
2. Wifi power test fail, please re-test, failed again to check whether the devices U808 on the launch access has
solder skips, and channel RC device.
3. WIFI test EVM fail. This major and power, as well as the freq error, if the power is too high or the freq too big
EVM may also lead to excessive, please re-test.
4. WIFI RX fail, main receiving sensitivity fails to pass, check whether U803 has solder skips. Generally, production
line testing has not shielded box, RX vulnerable to external signal interference, If come across such problems, can
change the channel to do the test.
Bluetooth main problem
：
Bluetooth does not need calibration, only need to check the function, if unable to search the device or Bluetooth
can not be opened, check whether the U801 is welding bad or body bad.
GPS main problem
：
GPS signal first enters the GPS saw U805 and U806, after saw, input to SR2351 chip within, demodulate signal .
The GPS fails to search satellite or the search- satellite GPS_REG_ON value is high, focus on checking the U805 and
U806 filters paste partial or Weld, then check the tcxo power supply of VDDRF0, four voltage normal check whether
the UART single working. If the power supply and may UART no working ,please check the MCP SR2351.