Wcdma Rx-Synthesizer Troubleshooting Diagram - Nokia NHM-1 Series Troubleshooting Instructions

NHM-1
Troubleshooting instructions

WCDMA RX-synthesizer troubleshooting diagram

Activate RX synthesizer by setting
Ch. 10700 and pressing "Update"
Iin Rx Control ( WCDMA) window.
Measure the DC-voltage in G800
control voltage input, or in C820.
I Is it between 2.0 ... 2.5 V ??
NO
Check VCO output at 1 GHz span,
when center in 4280MHz
Iis the signal on incorrect frequency
NO SIGNAL
If there is no output signal,
Check the supply voltage for VCO,
measure from C813, L804.
Do you see VR6 regulator output at
ca. 2.8 V ??
YES
Check balun T802 ( not
shorted ).
OK ?? NO
YES
Replace G800 VCO
module
Page 34
Is VCO output frequency 4280 MHz
YES
and output level > -10 dBm ??
Measure with high impedance
probe.
Check loop filter components
YES
(joints) C816,C818, C820 and
R800, R802 and balun T802.
Check DC-voltage for VR1A from
C802 , is it ca. 4.7 V.
Check reference from VCTCXO
(19.2MHz) in C872.
OK ?
NO
Fix T802.
Figure 21: WCDMA Rx synthesizer troubleshooting
Nokia Corporation.
CCS Technical Documentation
NO
NO
I - if VR1A is e.g. 0 Vthen UEM
and connection into it must be fixed.
- Otherwise components around
G800 needs to be fixed.
- if this doesn't help change N810
(REX)
Check UEM and load
for VR1A (note: VR1A
is used by GSM
synthesizer).
YES
Synthesizer OK,
Selftest fail for other
reason
YES
Replace G800 VCO
module
Issue 1 11/03