User Guide

CCS Technical Documentation Troubleshooting — RF
RH-17
Issue 1 04/2003 Nokia Corporation Confidential Page 45
NOTE: Troubleshooting CDMA transmitter is same as Analog, differences are in PDM set-
tings. See Table 1 for PDM settings.
Table 3: DC probing for Cell/AMPS Transmitter
UHF LO at 1009.62 MHz for chan-
nel 384
At N601 Robin
TP20 Power
approx.5 dBm.
Measured with
RF probe
Check to see if LO is present. If no
LO is present, check N601, C666,
C519, C514, L501 and N502. Check
regulator voltages VR2 and VR6 are
at 2.78 Vdc. Proceed to Table 5 for
further UHF LO troubleshooting.
VHF LO at 346.2 MHz for cell band,
any channel
TP27
You can take RF
probe and ver-
ify presence of
LO at R613, but
this won’t
measure ampli-
tude accurately)
Should measure
power at ~
-6 to -12 dBm.
Measured with
RF probe
Check that control voltage at TP28
is at 1.45 Vdc. Check loop filter
components C612, C613, R607,
R605, C632, R606. Check Resonant
components C629, V602, C637,
V601, C630, C631, L611, C638 and
R613. Check VCO_BAND compo-
nents R609 and C618, make sure
voltage VR3 is present at 2.78 Vdc.
Power Detector TP33
TP34
Measure accord-
ing to Table 4
Check N806, L801, R805, R801,
C807 and N601.
Item to check setting
DC probing
location on board
DC Voltage
Items to check if voltage
incorrect
TX RF AGC See Table 1 TP10 See Table 1 D400 (UPP), R433, C426, R434,
C427, C429, V420, N601, R604
TX IF AGC See Table 1 TP11 See Table 1 D400 (UPP), R427, C422, R428,
C423, C430, V421, N601, R611,
C607, R601,
Voltage VIO at 1.8 Vdc
PA AGC See Table 1 TP12 See Table 1 D400 (UPP), R430, C424, R431,
C425, C431, V422, N601, R621
PD_CELL High for TX
on, Low for
TX off
TP16 High=2.6v
Low=0v
N601, C649, N603 (pin 4)
VREFRF02 fixed TP17 1.35v D200, C606, N601
IREF_CEL variable TP19 2.95v PA_AGC, C811, N801, N601,
R630, R621.