Motorola APX 2000 Detailed Service Manual

Troubleshooting Charts: RX RF Failure 5-37
RX RF Failure – Page 4
3
Remove shield, SH16.
Measure RF levels at the
RF switch, U402, and
compute switch loss.
700: output side of C402 &
input side of R451.
Loss < 1 dB?
No
Measure RF levels at the SAW filter,
FL401, and compute filter loss.
700: Output side of R451 and output
side of C413.
Loss < 3 dB?
No
Replace
FL401
Measure RF levels at the RF
switch, U404, and compute switch
loss.
700: output side of C413 & output
side of C487.
Loss < 1 dB?
No
Yes
Measure RF levels at LNA
and compute LNA gain.
700: input side of C423 and
output side of R406.
Gain about
10 dB?
Yes
Yes
Yes
Measure RF levels at the
RF switch, U403, and
compute switch loss.
700: output side of R406 &
input side of R453.
Loss < 1 dB?
No
Measure RF levels at the SAW filter,
FL402, and compute filter loss.
700: Output side of R453 and input
side of R455.
Loss < 5 dB?
No
Measure RF levels at the RF
switch, U405, and compute switch
loss.
700: output side of R455 & input
side of C430.
Loss < 1 dB?
No
Yes
Measure RF levels at LNA
and compute LNA gain.
700: input side of C430 and
output side of R412.
Gain about
10 dB?
Yes
No
Yes
Replace
FL402
5
7
No
6
Check digital logic
to the RF switch
and replace U403 if
needed.
Check digital logic
to the RF switch
and replace U405 if
needed.
Check digital logic
to the RF switch
and replace U402 if
needed.
Check digital logic
to the RF switch
and replace U404 if
needed.
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.

Motorola APX 2000 Specifications

General

IP Rating	IP67
Operating Temperature	-30°C to +60°C
GPS	Optional
Bluetooth	No
Frequency Range	700/800 MHz
Power Output	1-5 W (VHF), 1-3 W (700/800 MHz)
Channels	Up to 1, 000
Battery Life	Up to 10 hours (digital)
Digital Protocol	APCO P25
Frequency	VHF: 136-174 MHz, UHF: 380-470 MHz, 700/800 MHz: 764-870 MHz
Power	1-3W (700/800 MHz), 1-5W (VHF)