Troubleshooting Flow Chart - Hytera MD78X Service Manual

UHF2 (450-520MHz 45W) Information
11.8

Troubleshooting Flow Chart

Receiver Circuit
No receive
Q920 (9V3A)
outputs normally?
Yes
Q902 (9V1A)
outputs normally?
No
Check Q902 and
Q903.
No
Check the power-
on circuit.
Yes
Normal signal
output from front pan-
el? [1]
Yes
IF signal (73.35MHz)
is normal? [2]
Yes
TP6101 outputs
normally? [4]
Yes
RF signal at TP6104
is normal? [6]
Yes
RF signal at TP6103
is normal? [7]
Yes
Check L809, L813
and M801.
No
Replace the front
panel.
No
The second LO is
normal? [3]
TP707 receives
18MHz signal?
Yes
No
TP6106 outputs
normally? [5]
Check D6106, T6100 and
T6101.
No
Check Q6102, D6103 and
D6104.
No
Check D6100, D6101 and
D6102.
312
Service Manual
No
Check Q701.
Yes
No
Check D702.
Check RX
No
VCO and LO
amplifier.
Yes