PAMS
Technical Documentation
NSC/W–1/3
Disassembly & Troubleshooting Instructions
Page 35
Original 11/99
19.44 MHz oscillator and 3–multiplier troubleshooting
VCTCXO
OUTPUT :
19.44 MHz
P:>0.8Vpp
Change G850
N
Check
AFC–signal from
C850
V: 1.1V
Note!
Check all soldering and supply voltages
for VCTCXO and RFC–buffer.
Check also coil L850 & capacitor C858.
Check resistor
R850
Check 2G PLL
(N880) pin 15
V:>0.3 Vpp
Change capacitor
C851
Check
RFC–buffer
output C857
Change capacitor
C853
Note !
Check all solderings and components of buffer.
Check 3X output
V: >150 mVpp
Change capacitor
C854
Note!
Check all soldering and components of multiplier.
Check also Vce, should be 1 V if not change V840
N
Y
Start COBBA_D
troubleshooting
G850
Check PLUSSA
supply voltages
Change PLUSSA
Y
Y
Start BB
troubleshooting
N
Y
Y
Y
Y
N
N
N
V:>0.3 Vpp