Motorola APX 2000 Detailed Service Manual

Troubleshooting Charts: RX RF Failure 5-39
RX RF Failure – Page 6
Check LNA:
Check DC bias voltages for U406 at
the base (pin 1) & collector (pin 3).
Is base voltage =
0.778 V? and
collector voltage =
1.554 V?
Check DC bias voltages of Q402 at
the base (pin 2 or 5) , collector (pin
6) & emitter (pin 1).
Is base voltage = 1.024
V? Collector voltage =
0.777 V? Emitter
voltage = 1.554 V?
Check DC input line voltages
and visually inspect and
replace defective
components if needed.
No
Yes
No
Yes
Replace
U406
Replace
Q402
Check LNA:
Check DC bias voltages for U407 at
the base (pin 1) & collector (pin 3).
Is base voltage =
0.778 V? and
collector voltage =
1.552 V?
Check DC bias voltages of Q403 at
the base (pin 2 or 5), collector (pin
3) & emitter (pin 4).
Is base voltage = 1.025
V? Collector voltage =
0.778 V? Emitter voltage
= 1.552 V?
Check DC input line voltages
and visually inspect and
replace defective
components if needed.
No
Yes
No
Yes
Replace
U407
Replace
Q403
6
7
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)