Hytera MD78X Service Manual page 622

Service Manual
Transmitter Circuit
Yes
Check PA,
antenna switch,
and low-pass
circuits.
Yes
No
Current is
normal? [1]
No
Check Q805.
No
Check Q804.
No
Check Q802 and
Q803.
VHF (136-174MHz 50W) Information
No Power Output
Power supply
works normally?
Control voltage is
low or high?[2]
High
TX VCO works
normally? 3]
Yes
Q805 works with
normal power? [4]
Yes
Q804 works with
normal power? [5]
Yes
Q802/Q803 work
with normal power?
[6]
Yes
Completed
609
No
Check the power
circuit.
Low
Check U801.
No
Refer to FGU flow.