Tdma1900 Uhf Synthesizer 2 Ghz (Dualbander); Ghz Uhf Synthesizer Troubleshooting - Nokia NSC/W–1/3 Series Disassembly & Troubleshooting Instructions

PAMS
Technical Documentation
TDMA1900 UHF Synthesizer 2 GHz (ONLY DUALBANDER)
The 2GHz UHF synthesizer generates the needed injection frequencies for
TX and RX chain. The output frequency of the VCO depends on the control
voltage supplied by the PLL circuit.

2 GHz UHF synthesizer troubleshooting

Is Frequency
locked ?
What is VCO output
level? G860
P:~0 dBm
Check local input
level of frontend
(N721, pin 1)
P:~0 dBm
Check feedback
input level of
N880, pin 6)
P:~–10 dBm
Check N880
pin 11 (SCLK):2.8V
pin 12 (SDATA):2.8V
pin 13 (SENA2):2.8V
SENA is 0 during SCLK
and SDATA
Original 11/99
Disassembly & Troubleshooting Instructions
N
N
Change G860
Y
N
Check R867
N
Y
N
Check R886
Y
N
Start BB
troubleshooting
NSC/W–1/3
Note!
Frequency = 985.23...1010.2
Vcnt = 1.2...3.6 V , C861
Note!
Check all soldering & missing components
and supply voltage.
Note!
Check N880
supply voltages
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