Rx Signal Paths; Antenna Switch (Rx/Tx Switch); Fig 17 Receiver Fault Chart 8; Fig 18 Receiver Fault Chart 9 - Nokia NPL-4 Series Troubleshooting Instructions

Nokia Customer Care
Phoenix:
Phone: local mode
RF Controls:
Active Unit: Rx
Op. Mode: Continuous
Rx/Tx channel: default (mid)
AGC: 12
Signal Generator:
Level: –55dBm
Frequency: calculated from Phoenix
(no offset)
Spectrum Analyzer:
Center Freq: calculated from Phoenix
RBW 20kHz
Check Rx SAW filter of selected band:
GSM850/900 Z808
output both lines > -80dBm
GSM1800 Z807
output both lines > -80dBm
GSM1900 Z806
single output > -74dBm
Yes
If selected band = GSM1900
No
Spectrum Analyzer:
Check external LNA V802:
Output signal pin 3 > - 56dBm
Spectrum Analyzer:
Check balun T801:
Both output signals at pin 3+4 > - 62dBm
RF ASIC N500 seems to be
defective. Exchange N500.

Rx signal paths

Antenna switch (RX/TX switch)

RF signal is fed directly from the antenna-pad (J908) to the antenna switch (Z809).
This switch has the function of a diplexer, which consists of two combined paths (low
pass/high pass filter combination), a GSM850/900 and a GSM1800/1900 path. The GSM
850/900 input signals pass the switch to the Rx1 output. Via a switch the GSM 1800
input signals pass to Rx2 output and GSM 1900 to Rx3 output, depending on the control
Copyright © 2005 Nokia Corporation. All rights reserved.
Issue 2 05/05
Company confidential
Figure 17: Receiver Fault Chart 8
1)
No
Figure 18: Receiver Fault Chart 9
Yes
Oscilloscope:
1)
Check voltages for V802:
No
Yes
1)
Yes
No
Change V802
Troubleshooting Instructions
Change Rx SAW
(Z806, Z807, Z808)
depending on selected band
Note! 1) RF levels are dependent on RF probe
1)
Note :
RF levels are dependent on RF probe and have to be validated
and have to validated with a known good sample.
with a known good sample.
Voltage at C827 = 2.6V
Voltage at C801 = 0V
Yes
No
Note! 1) RF levels are dependent on RF probe
1)
Note :
RF levels are dependent on RF probe and have to be validated and have to validated with a known good sample.
with a known good sample.
NPL-4/5/
Receiver
Fault Chart 8.
Receiver
Fault Chart 9.
Check supply
filter components
No
around V802 and
RF ASIC N500
Change T801
Page 25