Furuno 841, 821 manual Troubleshooting table

4.4 Troubleshooting

Table 4-2 contains simple troubleshooting procedures which you can follow to try to restore normal operation. If you cannot re- store normal operation, do not attempt to check inside any unit of the radar system. Any repair work is best left to a qualified technician.

Table 4-2 Troubleshooting table

If...	But...	Then...
you pressed the	the control panel does	• try adjusting the control panel back-
[POWER] key to turn	not light	lighting on the Brilliance/Backlighting
on the radar		menu.
		• battery may have discharged.
		• check fuse in power cable.
	nothing appears on	• try adjusting the tone.
	the display or display	(Extreme ambient temperature may
	contrast is poor	affect display tone.)
	characters are	• request service.
	distorted
the radar has	the antenna does not	• the problem may be in antenna unit.
warmed up and you	rotate	Request service.
pressed the
	characters and	• have a qualified technician check the
[ST-BYTX] key to
transmit	indications are	set.
	abnormal
you have adjusted	neither noise nor	• check signal cable for damage.
the gain with FTC	targets appear
and STC off	(indications and
	markers do)
	neither indications nor	• check signal cable for damage.
	markers appear (noise
	and targets do)
	the sweep (radial line	• the problem may be in the antenna
	sweeping around the	unit. Request service.
	display) is not
	synchronized with
	antenna rotation
	there is no change in	• request service.
	sensitivity.
a key is pressed	nothing happens	• key may be faulty. Request service.

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