Troubleshooting Flow Chart - Hytera MD78X Service Manual

Service Manual
5.4

Troubleshooting Flow Chart

Replace U901.
No
U901 outputs 3.3V
normally?
Yes
Check UART.
Check R368 and
R370.
Start
The radio can position
normally?
No
The PC-based
No
software (e.g.SiRF
Demo) shows GPS
communication?
Replace the
normally?
Peripheral
components work
normally?
Yes
RX signal is
`
Yes
Connector works
normally?
Active antenna is
damaged?
Replace the active
21
GPS Circuit
GPS
module.
Yes
Antenna
No
Replace the
works
antenna.
Yes
No
components.
Yes
weak?
No
Yes
Yes
antenna.
Replace
defective
Replace
connector
W321.