Furuno FR-2805 Series - Manual (Page 21)

1-6
1.4 CRT Brilliance
Operate the BRILL control on the control
panel of the display unit to adjust the en-
tire screen brightness. Note that the opti-
mum point of adjustment varies with
ambient light conditions, especially be-
tween daytime and nighttime.
BRILL A/C RAIN GAIN A/C SEA
Brilliance
control
Note: The CRT brilliance should be ad-
justed before adjusting relative brilliance
levels on the BRILLIANCE menu to be
explained later.
1.5 Tuning the Receiver
Auto tune
The radar receiver is tuned automatically
each time the power is turned on, thus
there is no front panel control for tuning
purpose. The tuning indicator and the la-
bel AUTO TUNE at the top right corner of
the display unit show the tuning circuit is
working. If the label AUTO TUNE is not
displayed, check that the TUNE selector
in tuning compartment is in the AUTO
position.
Manual tune
If you are not satisfied with the current
auto tune setting, follow these steps to
fine-tune the receiver:
1. Set the TUNE selector in the tuning
compartment to MAN for manual tun-
ing.
ORIGIN MARK VECTOR TRUE/ REL VECTOR TIME
TUNE control
TUNE selector
2. Push the tune control so that it pops
up.
3. While observing the picture on the 48
mile scale, slowly adjust TUNE control
and find the best tuning point.
4. So the TUNE selector to AUTO and
wait for about 10 seconds or four scan-
ner rotations.
5. Make sure that the radar has been set
to the best tuning point. This condition
is where the tuning indicator lights to
about 80% of its total length.
6. Push the TUNE control into the re-
tracted position.
This LED lights if video lockup is associated
with fundamental malfunction of CPU.
ST-BY switch for
quick start
Video Lockup Recovery
Video lockup, or picture freeze, can occur unex-
pectedly on digital rasterscan radars. This is
mainly caused by heavy spike noise in the power
line and can be noticed by carefully watching the
nearly invisible sweep line. If you suspect that the
picture is not updated every scan of the antenna
or no key entry is accepted notwithstanding the
apparently normal picture, do Quick Start to
restore normal operation:
1. Turn of the power switch and turn it on again
within five seconds.
2. Push the ST-BY switch in the tuning compart-
ment.
3. Push the Transmit switch labeled ST-BY/TX
for Transmit status.