NSW-5
Disassembly and Troubleshooting Instructions
PAMS Technical Documentation
Page 48
Issue 1 10/00
Nokia Mobile Phones Ltd.
VHF VCO Troubleshooting
Is oscillator
locked ?
N
Check EROTUS (N750)
(SCLK):2.8V
(SDATA):2.8V
(SENA1):2.8V
SENA is 0 during SCLK
and SDATA
Check oscillator
output level and
frequency at
C744
Check N770
Note!
Note!
SENA1 = EROTUS PLL
Y
N
Check PD1 at
C790
V=1–2 (LB)
=2.8–3.8 V (HB)
Y
N
N
Change N770
Note!
Check all solderings,missing
components and supply voltage
VR3.
Check
EROTUS
supply voltages
Note!
Check all components and soldering
The Oscillator is locked, when
the frequency and Vcnt are
stable.
Frequency=322.38/392.46MHz
Vcnt=1
…
.3.8V,C790
Y
Change V723
Note!
Check all solderings and
missing components
Start BB
troubleshooting
N
Check
EROTUS
supply voltages
Check
EROTUS
supply voltages
Start BB trouble
shooting
Change
EROTUS
N
Y