RH-10
Troubleshooting
CCS Technical Documentation
Page 26
Nokia Corporation Confidential
Issue 1 09/2002
7 RSSI should be /- 2 dB of actual RX signal above -104 dBm and +2/-4dB
below -104 dBm
8 In AMPS, ensure 230 mV on I,Q traces of Batman out, probing point 38 of
Figure 3.
9 Use CW signal for AMPS, use CDMA signal for CELL. Call box can generate both
AMPS ch 384 HighGain
127
215
173
1.19
-65 dBm
CELL ch 384 LowGain
-1
106
60
0.99
-65 dBm
CELL ch 384 HighGain
-119
-3
-64
0.78
-95 dBm
Table 5: RF Probing for Cell CDMA and AMPS Front-end Receiver
Probing point
Probing
location on
the board
Probed Absolute Power (dBm) or
gain/loss (dB)
What to check if RF power not
correct (soldering, shorts, DC
power applied if active, correct
voltage of DC signals, otherwise
replace)
Cell duplexer
(Z803) out =
Alfred (N750) in
32, Figure 1
Loss = 2-4 dB through duplexer
Z803, L750, N750 (VRX)
Alfred (N750) LNA
out = cell RX saw
(Z751) in
33, Figure 2
Gain = 12-14 dB for high gain
mode (GAIN_CTL=high. Use RF
AGC status window to monitor
state)
Loss = -3 to -5dB for low gain
N750. Also, IF_SEL low for CDMA
and high for AMPS. Ensure
GAIN_CTL high if RX power is
below the LNA switch point. Z751,
C755, L752, C757, R721, C753,
R723, C756
Cell RX saw (Z751)
out = Alfred
(N750) mixer in
34, Figure 2
Loss = -1-3 dB through SAW filter
Z751, N750, R722, C750, R723,
C756, L757, C758
UHF LO at
1009.62 MHz in
Cell CDMA/AMPS
for channel 384
10, Figure 1
Can probe on
top of plastic
to check for
presence of LO,
but won’t read
accurate
power
Approx -3 dBm
If LO is present but off freq (could
be off by hundreds of MHz), then
VCO G502 is at least putting out a
signal. If LO not present, check
G502, L509, R505, R515 first. Else,
check C511, C501, C532, C550,
R550, C509, R503, C508, R508,
C518, N501, R506, C516, C515,
C521, R513, C504. Lastly, check
R523, R519, R509
Table 4: Receiver Probing (PDM and voltage)
PDM
lower limit
PDM
upper limit
PDM mean Voltage for
PDM mean
RX power in
