CCS Technical Documentation
Troubleshooting — RF
NPD-1
Issue 1 11/2002
Nokia Corporation Confidential
Page 31
UHF LO at 1009.62
MHz for channel
384
10E, Figure 5.
Can probe on
top of plastic
to check for
presence of LO,
but won’t read
accurate
power.
Power approximately -3 dBm
Check to see if LO is present. If no
LO present, check R515, C511,
C501, C532. Make sure there is
2.7v at TP 10B. If voltage is less
than 2.6v, refer to Baseband regu-
lator troubleshooting. If voltage is
2.7v, check G502 at TP 10A with a
FET probe to see if UHF LO is
present. Check that 19.2MHz clock
is present at TP 10C. If LO is
present but unlocked, check C518,
C508, R508, R503, C509, R550,
and C550. Pay attention to C508,
as it is easily damaged. If LO is
present and locked, but doesn’t
appear at TP 10E, check R519,
R509, C506, N502, L501, C514, and
C519.
VHF LO at 346.2
MHz for cell band,
any channel
11a, Figure 5
(you can touch
top of plastic
to verify pres-
ence of LO, but
this won’t
measure
amplitude
accurately)
N601, C612, C613, R607, R605,
C632, R606, C618, R609, C629,
V602, C637, V601, C630, C631,
L611, C638, R604, R601, R602,
R613
Table 3: DC probing for Cell/AMPS transmitter
Item to
check
Setting
DC probing
location on
board
DC Voltage
Items to check if voltage
incorrect
TX RF AGC
See Table 1
12, Figure 8
See Table 1
D400 (UPP), R433, C426, R434,
C427, C429, V420, N601
TX IF AGC
See Table 1
13, Figure 8
See Table 1
D400 (UPP), R427, C422, R428,
C423, C430, V421, N601
PA AGC
See Table 1
14, Figure 8
See Table 1
D400 (UPP), R430, C424, R431,
C425, C431, V422, N601
PD_CELL
High for TX on,
Low for TX off
49, Figure 5
High=2.6v
Low=0v
N601, C649, N603 (pin 4)
VREFRF02
fixed
50, Figure 5
1.35v
D200, C606, N601
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)