Motorola APX 6000 Service Manual

5-40 Troubleshooting Charts: RX RF Failure
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: 485.075 MHz
700: 769.0625MHz
800: 860.0625MHz
Measured with a high impedance probe for relative comparisons
and troubleshooting only. Actual S21 gain or loss may differ if
the test point is not 50 ohms.

Motorola APX 6000 Specifications

General

Frequency Range	700/800 MHz, VHF, UHF Range 1, UHF Range 2
IP Rating	IP67
P25 Phase 1 & 2	Yes
GPS	Yes
Encryption	AES, DES
Power Output	1-3 Watts (700/800 MHz)
Operating Temperature	-30°C to +60°C
Intrinsically Safe	Yes
Bluetooth	Yes (Bluetooth 4.0)