Nokia RH-17 Series Troubleshooting - Rf page 49

CCS Technical Documentation
Cell RX saw (Z751) out=Alfred
(N750) mixer in
UHF LO at 1009.62 MHz in Cell
CDMA/AMPS for channel 384
Alfred (N750) Mix_Out= at 128.1
MHz Alfred (N750) IFA_In=
Alfred (N750) IFA_In=
Alfred (N750) AMPS out=
Alfred (N750) AMPS out=
Amps RX IF filter(Z752)
in=
AMPS RX IF filter (Z752)
in=
AMPS RX IF filter (Z752)
out=
AMPS RX IF filter (Z752)
out=
Batman (N701) in=
Issue 1 04/2003
TP37
TP38
TP39
Table 10: RF Probing for AMPS Back End Receiver
TP40 This point not 50
ohms. Will
measure approx
+ 3 dB gain from
IFA Amplifier.
Using results
fromTP39 as ref-
erence.
TP41 Same results as
above if match-
ing components
are correct
TP42 This point not 50
ohms. Will
measure Loss of
=2-4 dB through
Crystal filter
TP43 You will meas-
TP44 ure usually –10
dBm less than
previous test
point.
Nokia Corporation
Troubleshooting — RF
Loss=1-3 dB Z751, N750, L757 and
through SAW C758.
filter
Approx. Check to see if LO is
-3 dBm present. If no LO is
present, check L771, R505
and L520. Refer to Table 5
for additional UHF LO
troubleshooting.
Check LP filter compo-
st
Rx 1 IF at
nents L753, C759, C766
128.1 MHz is
and L770.
usually
-5.0 to –7.0
dBm less than
original Rx
input ampli-
tude setting at
RF Test Set.
Ensure IF_SEL low for CDMA and high for
AMPS, as in Table 11), N750, R765, C750,
L757 and also reference next step(TP41) to
ensure that impedance matching compo-
nents from N750 to Z752 are correct.
Check Z752, C784, L764, C781, L762, C783,
C786, C761, L754, C782 and C767 also
ensure dc voltage Vrx is present at L762.
Z752, L765, C777, L766, C778, L768, L767,
C779, N701 (VR5, VR7, VIO)
Z752, L765, C777, L766, C778, L768, L767,
C779, N701 (VR5, VR7, VIO)
Confidential
RH-17
Page 49