Troubleshooting Diagram For Wcdma Receiver - Nokia NHM-1 Series Troubleshooting Instructions

NHM-1
Troubleshooting instructions

Troubleshooting diagram for WCDMA receiver::

y p g
Apply –50 dBm level continous
wave RF signal @2141MHz into
antenna connector.
Measure J800 ...J803 testpoints
with a oscilloscope. Is there ca. 0.5
Vpp swing sinewave at 1 MHz and
DC-level 0.7 V in all testpoints ??
YES
WVCDMA RX path is OK, TIKU
RXIQ-input can be faulty.
Press "RF Stop", from RX Control
UI.
Activate:
/Testing/Self Test " IQ loopback
test"
PASS ??
YES
WCDMA RX
RF-path is
functional.
Enable RX Control with pressing
"Update".
Check Vref2 output DC-voltage
from the pad for R843 ( not assembled
component), is it ca. 0.75 Vdc ??
Check REX ( N810 ) solderings,
especially for Vre1..Vref3?
YES
WCDMA RX RF-path is
functional.
Check BB (TIKU,D400)
Replace REX (N810)
Page 30
p
Press "RF Stop" and record current
consumption, press "Update" – did
current increase by ca. 100 mA ??
NO
Use spectrum analyzer with a high
impedance RF probe (compensate
loss * ) to measure signal levels on the
RF-route from antenna.
Measure at 2141MHz in duplexer input
( antenna port ) and RX output.
Are signal levels close to –50 dBm
( RX output about –1.5...2 dB
compared to antenna port) ???
NO
Measure signal levels from C890 and
C892.
Signal levels ca. –58 dBm in both
ones ( should be the same)
Measure signal levels from both ends
of R807.
Signal levels should be ca. –61 dBm.
Measure RX VCO output from G800.
Signal at 4280 MHz > -10 dBm ??
NO
Measure RX I-signal from C830&C831
and RX Q-signal from C832&C833.
0.5 Vpp 1 MHz sinewave should be
seen in all capacitor terminals.
Figure 20: WCDMA RX troubleshooting
Nokia Corporation.
CCS Technical Documentation
YES
YES
YES
YES
YES
YES
Check PWB connection
from C830&C831 and
C832&C833 to J800...J803
Check ref.-voltage
NO
across R816 and
R834 (1.35 V).
Check supply
VR4=2.8V (C800)
and
VR5=2.8V(C850).
If OK replace N810
Check X962 and
NO
duplexer Z960
Check T800,
NO
L810&L812,
C890&C892
Check Z800,
NO
L801,C810,C811
and C842,C844.
WCDMA RX
NO
synthesizer
troubleshooting.
Check REX (N810).
NO
' NOTE:
In this case HP10020A passive
20:1 ( 1kOhm) probe was used -->
This divider causes at least 26 dB
level offset.
Issue 1 11/03