NSW-5
Disassembly and Troubleshooting Instructions
PAMS Technical Documentation
Page 50
Issue 1 10/00
Nokia Mobile Phones Ltd.
TDMA1900 UHF Synthesizers
2 Ghz UHF synthesizer generates desired injection frequencies for TX
and RX chain. The output frequency of the VCO depends on the control
voltage of the PLL–circuit
2 GHz UHF Synth Troubleshooting
Is the fequency
locked ?
N
What is VCO output
level ?, G860
P:>–10 dBm
Check local input
level of frontend
(N721, pin 1)
P:>–10 dBm
Change G860
Check R863
Check feedback
input level of
N880
P=–10–0 dBm
Note!
Check all solderings, missing components
and supply voltage
N
Y
N
Y
N
N
Check N880
pin 11 (SCLK):2.8V
pin 12 (SDATA):2.8V
pin 13 (SENA2):2.8V
SENA is 0 during SCLK
and SDATA
Check C891
N
Start BB
troubleshooting
Note!
The Oscillator is locked, when the
frequency and Vcnt are stable.
Frequency=2046.27…..2106.15MHz
Vcnt=1….4V,C861
NOTE!
Check N880 supply voltages
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