NPD-1
Troubleshooting — RF
CCS Technical Documentation
Page 30
Nokia Corporation Confidential
Issue 1 11/2002
Table 2: RF/Analog Probing for Cell/AMPS Transmitter
Probing Point
Probing
location on
board
Probed absolute power (dBm) or
gain/loss (dB), or voltage (v)
Where to start checking if RF
power not correct (soldering,
shorts, DC power applied if
active, correct voltage of DC
signals, otherwise replace)
Robin (N601) out
= Balun (T604) in
2a and 2b,
Figure 5
easiest to probe on balun output as
per Table 1. Nominal loss through
balun=1dB, but will appear as
3-4 dB gain due to impedance dif-
ference. On Robin output, you may
see amplitude imbalance between
two sides of probing point 2 due to
impedance differences (less in cell).
N601 (ensure VREFRF02 is 1.35v as
in Table 2. Check AGC voltages/
PDMs as in Table 2), T604, L604,
L603, C640, C642, C907, N603
(including check for 3.6v on pin5),
D400 (including AGC voltage check
in Table 2)
Balun (T604) out =
Tomcat (N603) in
3, Figure 5
See Table 1
T604, C640, C642, L603, L604,
N601, C907, N603 (including check
for 3.6v (Vbat) on pin 5 and 2.6v on
pin 4)
Tomcat (N603) out
= TX SAW filter
(Z604) in
4, Figure 5
Gain = 12-16 dB through Tomcat
N603 (also ensure 3.6v on pin 5
and PD_CELL high as in Table 2),
N601, C649, C639, Z604, N801
(Vbat)
TX SAW filter
(Z604) out = cell
PA (N801) in
5, Figure 5
Loss = 2-3 dB through SAW
Z604, N603, N801 (Vbat)
Cell PA (N801) out
= cell isolator
(Z802) in
6, Figure 5.
Probing here
not recom-
mended unless
necessary; best
to measure on
RF connector
PA has variable gain, see Table 1.
Best to measure on RF connector.
N801 (including: check 3.6v on
Vbat), Z802, R805, R801, L801),
D400 (including AGC voltage check
in Table 1), N601 (since Iref, also
check PA_AGC as in Table 1)
Cell isolator
(Z802) out = cell
duplexer (Z803) in
7, Figure 5.
Probing here
not recom-
mended unless
necessary; best
to measure on
RF connector
Loss = 0.6 dB through isolator. Best
to measure on RF connector as in
Table 1.
Z802, N801 (Vbat), R805, R801,
Z803
Cell duplexer
(Z803) out =
diplexer (Z805) in
(In singlemode
phones, a resistor
replaces the
unused duplexer:
R810 for PCS only,
R811 for Cell only)
8, Figure 5.
Probing here
not recom-
mended unless
necessary; best
to measure on
RF connector
Loss = 1-3 dB through duplexer
Z803, Z805, Z804, L750, N750,
X814. If no cable connected to
X814, then additionally: X811.