NPD-1
Troubleshooting — RF
CCS Technical Documentation
Page 38
Nokia Corporation Confidential
Issue 1 11/2002
UHF LO at 2088.1
MHz for PCS
channel 600
10D, Figure 7.
Can probe on
top of plastic
to check for
presence of LO,
but won’t read
accurate
power
Approx –3 dBm
Check to see if LO is present. If no
LO is present, check R515, C511,
C501, C532. Make sure there is
2.7V at TP 10B. If voltage is less
than 2.6V, then refer to baseband
regulator troubleshooting. If volt-
age is 2.7V, check G502 at TP 10A
with a FET probe. Check that the
19.2MHz clock is present at TP
10C. If LO is present but unlocked,
check C518, C508, R508, R503,
C509, R550, and C550. Pay partic-
ular attention to C508, as it is eas-
ily damaged. If LO is present and
locked, but doesn’t appear at TP
10D, then check R505, R507, L771.
Table 11: RF probing for Cell CDMA and PCS back end receiver
Probing point
Probing
location on
board
Probed absolute
power (dBm) or gain/
loss (dB)
Where to start checking if RF
power not correct (soldering,
shorts, DC power applied if
active, correct voltage of DC
signals, otherwise replace)
Alfred (N750)
mixer out= CDMA
RX IF saw (Z753)
in
46, Figure 6
This point not 50
ohms. Will
measure approx -14
dBm for -52 dBm
input and RX AGC
PDM=225.
N750 and supporting components
(Also ensure BAND_SEL low for
Cell CDMA and high for PCS as in
Table 9. Also IF_SEL low for CDMA
as in Table 9), L754, C782, C767,
C761, C786, Z753
CDMA RX IF saw
(Z753) out= Bat-
man (N701) in
47, Figure 6
This point not 50
ohms. Will
measure approx
-47 dBm for -52 dBm
input and RX AGC
PDM=225
Z753, N750 and supporting com-
ponents (including check for proper
voltages on Alfred signaling as in
Table 8), L754, C782, C767, L759,
C770, C771, C772, L760, L761,
N701
Batman (N701)
out= UEM (D200)
in
40, Figure 6
Easiest to use RSSI,
see Table 6.
N701 (VR5, VR7, VIO, ensure 1.35v
on VREFRF01 as in Table 9, also
check RX_IF_AGC as in Table 9),
R705, C704, R706, C706, C701,
C714, R703, R702, C715, R704,
V701, C716, L701, C702
Table 10: RF probing for PCS front end receiver
Probing point
Probing
location on
board
Probed absolute
power (dBm) or gain/
loss (dB)
Where to start checking if RF
power not correct (soldering,
shorts, DC power applied if
active, correct voltage of DC
signals, otherwise replace)