Nokia NPD-4 Series Technical Documentation Manual page 33

CCS Technical Documentation
Probing
Probing point location on
board
PCS PA (N802) out 21, Figure 5.
= PCS isolator Probing here
(Z801) in not recom-
men-ded
unless neces-
sary. Best to
measure on RF
connector.
PCS isolator 22, Figure 5
(Z801) out= PCS
duplexer (Z804) in
PCS duplexer 23, Figure 7
(Z804) out =
diplexer (Z805) in.
In singlemode
phones, a resistor
replaces the
unused duplexer:
R810 for PCS only,
R811 for Cell only.)
Diplexer (Z805) 9, Figure 7
out= RF connector
(X814) in.
UHF LO at 10E, Figure 5.
2088.1 MHz for Can probe on
PCS on channel top of plastic
600 to check for
presence of LO,
but won't read
accurate
power
VHF LO at 11a, Figure 5
416.2 MHz for
PCS, any channel
Issue 1 02/2003
Table 4: RF/Analog Probing for PCS transmitter
Measured power (dBm) using RF
probe, or gain/loss (dB)
See Table 1. Best to measure on RF
connector.
Loss=0.6 dB through isolator
Loss=3 dB through PCS duplexer,
TX to ANT port
Loss=0.5 dB through diplexer
Approx –3 dBm
Nokia Corporation
Troubleshooting — RF
What to check if RF power not
correct (soldering, shorts, DC
power applied if active, correct
voltage of DC signals, otherwise
replace)
N802 (3.6v on Vbat), Z801, R802,
L801, L802, D400, N601 (since Iref,
also check PA_AGC as in Table 5)
Z801, Z804
Z801, N802 (Vbat), R802, Z804,
Z801, Z805, L750, N750, X811
X814
Z803, Z804, L750, N750, C801,
L812, X814. If no cable connected
to X814, then additionally: X811
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
19.2 MHz 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
10E, then check R519, R509, C506,
N502, L501, C514, and C519.
N601, C612, C613, R607, R605,
C632, R606, C618, R609, C629,
V602, C637, V601, C630, C631,
L611, C638, R604, R601, R602
Confidential
NPD-4
Page 33