Troubleshooting - Furuno FM-4850 Operator's Manual

MAINTENANCE AND TROUBLE
SHOOTING

14.2 Troubleshooting

When the FM-4850 does not work properly, you can follow the following
troubleshooting procedures to fix it.
Problem
The radio cannot
be turned on.
The radio blows
the fuse when
connected to the
power supply.
The speaker
makes popping or
whining noise
while the engine
of the ship runs.
The sound is not
emitted from the
speaker of the
handset.
Possible Cause
No DC voltage to
the radio, or blown
fuse
Reversed polarity
of power wires
Engine noise
Accessory cable
FM-4850 Operator's Manual
Solution
Check the 10.8 to 15.6
Step 1
VDC battery
connections and the
fuse.
Long press the On/Off
Step 2
key to turn on the
handset.
Make sure the red wire
Step 1
is connected to the
positive (+) battery
post, and the black wire
is connected to the
negative (-) battery
post.
Step 2 Check the power cable
for DC voltage and
replace the fuse (8A
250V).
Step 1 Reroute the DC power
cable of the radio away
from the engine.
Add a noise suppressor
Step 2
on the power cable.
Change to resistive
Step 3
spark plug wires and/or
add an alternator whine
filter.
Check that the handset
Step 1
is physically connected.
Step 2 Check whether the
handset is broken or
short-circuited.
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