Furuno FM-4800, Operator'S Manual

Page: 88 / 135

FM-4800 Operator’s Manual
MAINTENANCE AND TROUBLES
HOOTING
79
14.2 Troubleshooting
When the FM-4800 does not work properly, you can follow the following
troubleshooting procedures to fix it.
Phenomena Probable Cause Solution
The radio cannot
be turned on. No DC voltage to the
radio, or blown fuse
Step 1 Check the 10.8 to 15.6
VDC battery connections
and the fuse.
Step 2 Long press the On/Off
key to turn on the radio.
The radio blows
the fuse when
connected to the
power supply.
Reversed polarity of
power wires
Step 1 Make sure the red wire 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).
The speaker
makes popping
or whining noise
while the engine
of the ship runs.
Engine noise
Step 1
Reroute the DC power
cable of the radio away
from the engine.
Step 2
Add a noise suppressor
on the power cable.
Step 3
Change to resistive
spark plug wires and/or
add an alternator whine
filter.
The sound is not
emitted from the
internal or
external speaker.
Accessory cable
Step 1
Check that the external
speaker cable (Purple &
Gray) is physically
connected.
Step 2
Check whether the
external speaker cable is
broken or short-circuited.
The sound is not
emitted from the
speaker.
Accessory cable
Step 1 Check that the cable
(Red & Black) is
physically connected.
Step 2 Check whether the