10-25
Chart 38 . VHF/UHF Transmitter RF
No/Low Power
TX Current
> 500 mA?
RF at RF
Connector,J2
Pin 2?
Replace U105
NO
YES
RF at
Cathode of
CR108?
RF Present
at Anode
of CR108?
RF Present
at Pin 5 of
U104?
Replace U104
Check Antenna
Switch Biasing
Circuits, L122,
L105, U101
Check Components
Between C147
and L128
Check antenna
switch
YES
YES
YES
YES
NO
NO
NO
Is T5 On
at C153?
B+ at
U105, Pin 5
(VHF)
5,6 (UHF)?
Replace U105
7.5V at
U105
Pin 2.4?
Voltage
at U105
Pin 3?
RF Voltage
at U105,
Pin 1?
Check Components
Between U105
and U201. If No
Fault Found,
Go To FGU
Troubleshooting
Chart C.31
YES
YES
YES
YES
YES
NO
Go to DC Switch
Routine Chart C.36
Check B+, E1 & E101
(VHF), E1, E2, E3 &
E101, E104 (UHF) and
Power Supply
7.5V at
U105
Pin 2,4?
Voltage
at U105
Pin 3?
RF Voltage
at U105,
Pin 1?
7V at
Collector
of Q101?
5V at
U101,
Pin 16?
7.5V at
Emitter of
Q101?
Check L102, L103 (UHF)
L102, L130 (VHF)
Voltage at
Q101 Base
is B+ Less
0.7V?
Go to FGU No Lo
Injection/TX Not
Lock Routine
Chart #4A
Check Power
Supply
Replace Q101
Replace U101
Voltage at U101
Pin 14 > 1V?
Replace U102
Check Detector
Circuit, CR102, (VHF),
CR101 (UHF), CR103,
R110, R111, U102
YES
NO
Replace U101
U101,
Pin 2,7
About 2.5V
to 4V?
U101
Pin 3
About 3.5V
Pin 6
About 1.5V?
NO
YES
NO
NO
NO
NO
NO
YES
NO
YES
YES
NO
NO
YES
YES
NO
NO
MAEPF-24393-O
Summary of Contents for ASTRO Digital Saber
Page 1: ... Digital SABER and R Portable Radios Detailed Service Manual ...
Page 19: ...1 14 Notes ...
Page 31: ...4 6 Notes ...
Page 37: ...5 6 Notes ...
Page 43: ...6 6 Notes ...
Page 81: ...12 4 Notes ...
Page 82: ... 6881076C10 68P81076C10 A Motorola 8000 West Sunrise Boulevard Fort Lauderdale Florida 33322 ...
Page 109: ...13 1 Block Diagrams Schematics Electrical Parts Lists and Circuit Board Details 13 ...
Page 111: ...13 3 NLD8892R VHF Transceiver Board Schematic Diagram 63B81094C71 O ...
Page 120: ...13 12 NUF6411K 800 MHz Transceiver Board Schematic Diagram 63B81094C75 O ...