Motorola APX 1000 Detailed Service Manual page 142

5-44
RX RF Failure – Page 11
14
Remove shield, SH16. Measure RF levels at
the SAW filter, FL401, and compute filter
loss.
output side of C413 and input side of C451
Loss < 2 dB?
Measure RF levels at LNA and compute the
LNA gain.
input side of C423 and output side of R406
Gain about 8.5dB?
Measure RF levels at the SAW filter, FL402
and compute the filter loss.
Input side of C453 and output side of C455
Loss < 2 dB?
Measure RF levels at LNA and compute LNA
gain.
Input side of C430 and output side of R412
Gain about 8.5dB?
5
Note: RF Test frequency used:
VHF: 154.275MHz
UHF1: 424.975MHz
UHF2: 485.075MHz
700: 769.0625MHz
800: 860.0625MHz
900: 938.0625MHz
Measured with a High Frequency Probe for relative comparisons and
troubleshooting only.
Actual S21 gain or loss may differ if the test point is not 50 ohms.
Replace FL401
6
Replace FL402
7
Troubleshooting Charts: RX RF Failure