Specifications

MT-550 53
10.3 Troubleshooting
Troubleshooting Chart
Symptom Probable Cause Corrective Action
Transceiver won’t turn On. No dc voltage, blown fuse,
faulty wiring.
Rotate VOL knob CW, check
buss voltage, and replace
fuse (6.3 Amp), check power
cable and connections.
Buzzing sound from
speaker with engine
running.
Ignition or charging system
noise.
Reroute dc power cable,
install noise filter on
alternator and dc power
cable, use resistive spark
plug wires.
Squelch control set too high,
volume control set too low.
Set SQ control full CCW, set
VOL CW.
Channel blocked by stuck
mic button.
Select a different channel.
Look for TX annunciator in
display.
No sound from speaker.
Faulty external speaker or
cable.
Unplug external speaker
cable.
Antenna. Have a technician test
transmitter output power
and antenna VSWR.
Reports of weak transmit
signals even when using HI
power settings.
Coaxial cable faulty. Inspect antenna cable
carefully for nicks. Wet coax
absorbs transmitter power.
Lat/Lon position display not
turned On.
Use Menu – Data Set – LL
Position, to turn On.
GPS cable faulty or
disconnected.
Check cable and
connections.
Latitude and longitude
coordinates are not
displayed.
GPS not operating or
position is invalid.
Make sure GPS is functioning
and output format is NMEA
0183 with GLL/GGA/RMC/
GNS sentence selected.