Nokia NPE-4 Service Manual page 11

Customer Care Europe & Africa
SCCE Training Group
No Service → → → → no RSSI
Set the RF generator to GSM 942.4 MHz at channel 37, RF level –55 dBm and also the phone to same frequency and channel.
Check RX I/Q signals at C721, C722 (See picture below)
Always measure in burst mode (with an oscilloscope in DC mode).
Oscilloscope settings:
Ampl: 200mV
Time/Div: 1ms/Div
AC/DC/GND: DC
If not ok, check 67.71 kHz at C714 (DtoS and Biquad filter).
Measurement points at C714 count from N600 Hagar side:
All measurements made in Burst Mode (with an oscilloscope in DC mode).
Oscilloscope settings:
Ampl: 500mV
Time/Div: 200µs/Div
AC/DC/GND: DC
If the signal is not ok, check in GSM the RX signal 942.4 MHz at channel 37, RF level –55 dBm at L626.
If the signal is not ok, check in PCN the RX signal 1842.4 MHz at channel 700, RF level –55 dBm at L616
If both RX signals not ok, check RX lines from N600 Hagar to X802 antenna connector for shorts or
disconnections.
If the RX signals are ok, check System Clk = 26 MHz at C752 (See picture at chapter "Electrical faults"/ Totally dead)
If also the System Clk is ok, check following voltages:
Check VR3 = 2.8 VDC at C602.
Check VR4 = 2.8 VDC at C601
Check VR5 = 2.8 VDC at C604
Check VR6 (VBB) = 2.8 VDC at C605
Check VR1A (VCP) = 4.7 VDC (supply for control voltage VC for SHF oscillator) at C600
Check VR7 = 2.8 VDC at C299 (supply voltage VCC for SHF oscillator)
Check VREF01 and VREF02 = 1.35 VDC at R726
If one of the upper described voltages is not ok, check UEM D200.
If all voltages are ok, change N600 Hagar.
© NMP 2002
CONFIDENTIAL
NPE-4 6310/NPL-1 6310i
Date 15.08.2002
At first pins (3/4)= DtoS I/Q;
and then pins (1/2)= Biquad (CM_F and CP_F I/Q).
DtoS
Checked by:
SCCE Training Group
11 (25)
Repairhints
Version 1.0 Approved
Biquad
Approved by:
SCCE