Motorola APX 2000 Detailed Service Manual

Troubleshooting Charts: RX RF Failure 5-41
RX RF Failure – Page 8
9
Clock
Synthesizer
Measure tuning
voltage (Vt) at
R608
CLK_SSI_RX
Vt = 3 Vdc?
10
Vt = 0 Vdc?
10
Remove SH2, inspect
clock oscillator circuit
at U601-19,20
Visual
examination
Replace Varactor
VR601
Repair
Defects
No No
No
Yes
Yes
Yes
No
10
Remove SH2,
inspect
components
Visual
examination
OK?
Check level shifters, U603 and U604 by
checking signal amplitudes using an
oscilloscope at R616, R617, R618. R616
and R617 belong to U603 and R618 belongs
to U604. Note: These resistors are not
placed. You will be probing the pads.
Repair
defects
No
Yes
Yes
Is the input side
pad of R616, R617
& R618 = 3 V?
Is the output side
pad of R616, R617
& R618 = 1.875 V?
Replace
Abacus,
U601
Replace level
shifters, either
U603, U604 or both.
Replace
Abacus,
U601
No
Yes
No
Yes
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)