Amps & Tdma800 Uhf Synthesizers; Ghz Uhf Synth Troubleshooting - Nokia NSW-5 Series Service Manual

PAMS Technical Documentation
AMPS & TDMA800 UHF Synthesizers
1 GHz UHF VCO (G880) generates the first injection for RX (869...897
MHz) and the final injection for TX (824...849 MHz). The output frequency
of the module depends on the DC–control voltage supplied by the ERO-
TUS in line PD2.

1 GHz UHF Synth Troubleshooting

Is the frequency
locked?
What is VCO output
level ?, G820
P:>–5 dBm
Check local input
level of frontend
(N701, pin 1)
P:>–5 dBm
Check feedback
input level of
EROTUS
(at C821)
P:>–5 dBm
Check EROTUS (N750)
(SCLK):2.8V
pin 44 (SDATA):2.8V
(SENA1):2.8V
SENA is 0 during SCLK
and SDATA
Issue 1 10/00
Disassembly and Troubleshooting Instructions
N
N
Change G820
Y
N
Check C822
N
Y
N
Check C821
and
Y
Start BB
troubleshooting
N
E Nokia Mobile Phones Ltd.
Note!
The Oscillator is locked, when the
frequency and Vcnt are stable.
Frequency=985.23 ..1010.16MHz
Vcnt=1 .4V,C831
Note!
Check all solderings,missing components
and supply voltage.
NOTE!
Check EROTUS supply voltages
NSW-5
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