PAMS
Technical Documentation
NSC/W–1/3
Disassembly & Troubleshooting Instructions
Page 37
Original 11/99
VHF VCO troubleshooting
Is oscillator
locked ?
N
Check PLUSSA (N401)
pin 54 (SCLK):2.8V
pin 55 (SDATA):2.8V
pin 56 (SENA1):2.8V
SENA is 0 during SCLK
and SDATA
Check oscillator
output level
P:~–20 dBm
Check V800 Vce
pin2
V:~2.0–2.5V
Note!
Check BAND–signal status
”1” = TDMA800&S
”0” = TDMA1900
Note!
SENA1 = PLUSSA PLL
SENA2 = 2G PLL (N880, pin 13)
Y
N
Check V800 Vce
pin5
Y
Y
N
Change V800
Note!
Check all solderings and
missing components
Check D801
V: opposite of
BAND
Change D801
Note!
Check all components and soldering
Start BB
troubleshooting
PLUSSA pin 8
V:~2.0–2.5V
N
pin 4
Check PLUSSA
supply voltage
Change PLUSSA
Start BB
troubleshooting
N
Y
Y