Blu LIFE 8, Service Manual, Page: 17 / 29

3.3.2 RF Part examine and Repair
3.3.2.1 Necessary condition
First we need to define the failure kinds according to the failed item then we begin the
analysis in details.
Receiver key parameters include: RX Level, RX Quality, BER, FER etc.
a. Confirm the analyzer station has been set up.
b. Configure Agilent 8960 or CMU200 set channel and band, set the TCH level(-60dbm)
power big enough, if no, it’s difficult to measure the signal by spectrum analyze(for
example, GSM:CH=62 or Freq=902.4MHz, TCH Level=-60dbm.DCS: CH=700 or
Freq=1747.4MHz,TCHLevel=-60dbm ).
c. The phone connecting to computer, power on and use the tool(META) control the phone,
set up the channel and band same to 8960 or CMU200(for example, GSM:CH=62 or
Freq=902.4MHz,TCH Level=-60dbm.DCS: CH=700 or Freq=1747.4MHz, TCH Level=-
60dbm), control the phone to receiving state, then check the result.
3.3.2.2 Troubleshooting to receiver circuit
Note: test on a good radio to get reference signal when you don’t know if the signal is right.
You can depend on your experience to repair, unlucky, if you not enough experience, you’d
better follow this document.
Step 1: Measure the received signal according to RX signal series.
Measure the signal with spectrum analyzer on RF connector pin1 to check if the
input signal is right. If wrong signal was detected it maybe RF connector cold solder or
defect. If the signal is right then measure if the signal of PA is right, if the signal is wrong
then check the circuit which between RF connector and PA.
Analog audio signal to Receiver