Hytera MD78X Service Manual page 473

UHF3 (350-400MHz 45W) Information
Transmitter Circuit
Yes
Check PA,
antenna switch
and low-pass
circuits.
Yes
No
Current is
normal? [1]
No
Check Q801.
No
Check Q805.
No
Check Q804.
No
Check Q802 and
Q803.
No Power Output
Power supply
works normally?
Control voltage
is low or high?
[2]
High
TX VCO works
normally? [3]
Yes
Q801 works with
normal power? [4]
Yes
Q805 works with
normal power? [5]
Yes
Q804 works with
normal power? [6]
Yes
Q802/Q803
work with normal
power? [7]
Yes
Completed
460
Service Manual
No
Check the power
circuit.
Low
Check U801.
No
Refer to FGU flow.