Tdma1900 Uhf Synthesizer - Nokia NSW-6 Series Disassembly & Troubleshooting Instructions

NSW-6
Disassembly & Troubleshooting

TDMA1900 UHF SYNTHESIZER

2GHz 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.
Is the fequency
locked ?
N
What is VCO output
levet ?, G881
P=–10–0 dBm
Y
Check local input
level of frontend
(N721, pin 1)
P=–10–0 dBm
N
Y
Check feedback
input level of
N870
P=–10–0 dBm
Check N870
pin 11 (SCLK):2.8V
pin 12 (SDATA):2.8V
pin 13 (SENA1):2.8V
SENA is 0 during SCLK
and SDATA
Page 46
N
Change G881
Check C889 &
N
C882
N
Check C888 &
L880
Start BB
N
troubleshooting
E Nokia Mobile Phones Ltd.
PAMS Technical Documentation
Note!
Frequency = 985.23...1010.2
Vcnt = 1.3...3.5 V , C887
Note!
Check all soldering & missing components
Issue 1 12/99