Nokia NPD-4 Series Technical Documentation Manual page 30

NPD-4
Troubleshooting — RF
Probing
Probing Point location on
board
Robin (N601) out 2a and 2b,
= Balun (T604) in Figure 5
Balun (T604) out = 3, Figure 5
Tomcat (N603) in
Tomcat (N603) out 4, Figure 5
= TX SAW filter
(Z604) in
TX SAW filter 5, Figure 5
(Z604) out = cell
PA (N801) in
Cell PA (N801) out 6, Figure 5.
= cell isolator Probing here
(Z802) in not recom-
mended unless
necessary; best
to measure on
RF connector
Cell isolator 7, Figure 5.
(Z802) out = cell Probing here
duplexer (Z803) in not recom-
mended unless
necessary; best
to measure on
RF connector
Cell duplexer 8, Figure 5.
(Z803) out = Probing here
diplexer (Z805) in not recom-
(In singlemode mended unless
phones, a resistor necessary; best
replaces the to measure on
unused duplexer: RF connector
R810 for PCS only,
R811 for Cell only)
Page 30
Table 2: RF/Analog Probing for Cell/AMPS Transmitter
Probed absolute power (dBm) or
gain/loss (dB), or voltage (v)
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).
See Table 1
Gain = 12-16 dB through Tomcat
Loss = 2-3 dB through SAW
PA has variable gain, see Table 1.
Best to measure on RF connector.
Loss = 0.6 dB through isolator. Best
to measure on RF connector as in
Table 1.
Loss = 1-3 dB through duplexer
Nokia Corporation
CCS Technical Documentation
Where to start checking if RF
power not correct (soldering,
shorts, DC power applied if
active, correct voltage of DC
signals, otherwise replace)
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)
T604, C640, C642, L603, L604,
N601, C907, N603 (including check
for 3.6v (Vbat) on pin 5 and 2.6v on
pin 4)
N603 (also ensure 3.6v on pin 5
and PD_CELL high as in Table 2),
N601, C649, C639, Z604, N801
(Vbat)
Z604, N603, N801 (Vbat)
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)
Z802, N801 (Vbat), R805, R801,
Z803
Z803, Z805, Z804, L750, N750,
X814. If no cable connected to
X814, then additionally: X811.
Confidential Issue 1 02/2003