Chart 36. Vhf/Uhf Transmitter Rf - Motorola ASTRO XTS 3000 Service Manual

No/Low Power
NO
TX Current
> 500 mA?
YES
YES RF at RF
Check antenna
Connector,J2
switch
Pin 2?
NO
Check Components RF at
YES
Between C147
Cathode of
and L128 CR108?
NO
Check Antenna
RF Present
YES
Switch Biasing
at Anode
Circuits, L122,
of CR108?
L105, U101
NO
Check Components
Between U105
and U201. If No
YES RF Present
Replace U104
at Pin 5 of Fault Found,
U104? Go To FGU
Troubleshooting
Chart C.31
NO
Replace U105
NO
About 3.5V
Replace U101
About 1.5V?
NO
Go to DC Switch
Is T5 On
Routine Chart C.36
at C153?
YES
B+ at Check B+, E1 & E101
U105, Pin 5 (VHF), E1, E2, E3 &
NO
(VHF)
E101, E104 (UHF) and
5,6 (UHF)?
Power Supply
YES
7V at
7.5V at 7.5V at NO
Collector
U105 U105
of Q101?
Pin 2,4? Pin 2.4?
YES NO
Voltage Voltage 5V at
NO
at U105 at U105 U101,
Pin 3? Pin 3? Pin B4?
YES YES
NO
RF Voltage RF Voltage 7.5V at
at U105, at U105, Emitter of
Pin 1? Pin 1? Q101?
YES
YES
Replace U105
Voltage at
Q101 Base
is B+ Less
0.7V?
U101
Pin E2
U101, NO
YES
Pin E3, C1
Pin C3
About 2.5V
to 4V?
Voltage at
U101 Pin A4
NO
> 1V?
YES
NO
Check Detector
Circuit, CR102, (VHF),
CR101 (UHF), CR103,
R110, R111, U102
Replace U102

Chart 36. VHF/UHF Transmitter RF

YES
Check L102, L103 (UHF)
L102, L130 (VHF)
Go to FGU No Lo
NO
Injection/TX Not
Lock Routine
Chart #4A
NO
Check Power
Supply
YES
Replace Q101
YES
Replace U101
MAEPF-26046-O
10-35