Nokia NPD-4 Series Technical Documentation Manual page 36

NPD-4
Troubleshooting — RF
Probing
Probing point location on
board
Alfred (N750) 36, Figure 6
mixer out= AMPS
RX IF saw (Z752)
in
AMPS RX IF filter 37, Figure 6
(Z752) out= Bat-
man (N701) in
Batman (N701) 40, Figure 6
out= UEM (D200)
in
VHF LO at 256.2 39, Figure 6
MHz
Item to check Setting
RX IF AGC See Table 6 for
PDM settings
BAND_SEL High=PCS
Low=Cell
GAIN_CTL High=LNA high
gain, Low=LNA
low gain (both
Cell & PCS)
IF_SEL High=
AMPS, Low=
CDMA
VREFRF01 fixed
Page 36
Table 8: RF probing for AMPS back end receiver
Probed absolute
power (dBm) or gain/
loss (dB)
This point not 50
ohms. Will
measure approx
-28 dBm for -52 dBm
input and RX AGC
PDM=225.
This point not 50
ohms. Will
measure approx
-46 dBm for -52 dBm
input and RX AGC
PDM=225.
See Table 6, RSSI most
useful.
Table 9: DC probing for receiver
DC probing
location on
board
60, Figure 6
54, Figure 7
55, Figure 7
56, Figure 7
57, Figure 6
Nokia Corporation
CCS Technical Documentation
What to check if RF power not
correct (soldering, shorts, DC
power applied if active, correct
voltage of DC signals, otherwise
replace)
N750 (Also ensure BAND_SEL low
as in Table 9. Also IF_SEL low for
CDMA and high for AMPS, as in
table 3d.), R765, C750, L771, R768,
C756, L770, L757, C758, L755,
C769, R750, L753, C759, C766,
C784, L764, C781, Z752
Z752, L765, C777, L766, C778,
L768, L767, C779, N701 (VR5, VR7,
VIO)
N701 (VR5, VR7, VIO, ensure 1.35v
on VREFRF01 as in Table 9, also
check RX_IF_AGC as in Table 9),
R706, C704, R705, R704, V701,
C716, L701, C702, C715, R702,
C714, R703, C701,
N701, C701, C714, R703, R702,
C715, R704, V701, C716, L701,
C702, R705, C706
Items to check if voltage
DC voltage
incorrect
See Table 6 for D400, R435, C428, C435, N701
typical voltages
High=2.4vmin, N701, N750, R768, C756, G502
Low=0.3v max
High=2.4vmin, N701, N750, R764, C753
Low=0.3v max
High=2.4vmin, N701, N750, R765, C750
Low=0.3v max
1.35 v D200, C706, N701
Confidential Issue 1 02/2003