Furuno FAR-2218-BB Operator's Manual page 210

6. MAINTENANCE, TROUBLESHOOTING
Problem
Marks, indications and
noise appear but no
echo (transmission
leak representing own
ship position is absent)
Picture not updated or
picture freeze-up
Incorrect orientation of
picture
Cannot operate radar
from on-screen boxes
Radar is properly tuned
but poor sensitivity
Range changed but ra-
dar picture not chang-
ing
Interference rejector is
inoperative (interfer-
ence rejection level not
displayed)
Echo stretch is ineffec-
tive (neither ES1, ES2
nor ES3 is displayed)
Range rings are not
displayed
6-6
Possible cause
1) TX high voltage protec-
tion circuit has activated.
2) Magnetron
3) MD board inside the an-
tenna.
4) SPU board inside the an-
tenna.
1) Rotary Encoder inside
the antenna unit.
2) SPU board inside the an-
tenna.
3) Video freeze-up
1) Rotary Encoder inside
the antenna unit
2) SPU board inside the an-
tenna unit.
3) MTR-DRV board inside
the antenna unit.
MAIN board - inside the Pro-
cessor unit.
1) Deteriorated magnetron
2) Detuned MIC
3) Dirt on radiator face
4) Water ingress to the
waveguide or other feed-
er line
5) Second trace echo rejec-
tion is ON
1) Defective range key
2) SPU board inside the an-
tenna.
3) Video freeze up
SPU board inside the anten-
na.
SPU board inside the anten-
na.
1) Adjust the brilliance of
range rings on the BRILL
menu to see if intensity is
increased
2) MAIN board
Remedy
1) Reset power to restore normal opera-
tion.
2) Check magnetron current.
Replace magnetron.
3) Replace MD board.
4) Replace SPU board.
1) Check the connection of signal cables.
2) Replace SPU board.
3) Turn the radar off, then on.
If the message "NO HEADLINE SIGNAL"
appears in orange letters inside the alert
box, the heading signal is lost or interrupt-
ed. Check the heading line signal cable
and board connections. If there is no prob-
lem with cables or connections, replace
the faulty board.
Replace MAIN board.
1) With the radar transmitting on 48 nm
range, check magnetron current. If
current is below normal, magnetron
may be defective. Replace it.
2) Check MIC detecting current. If it is be-
low normal value, MIC may have be-
come detuned. MIC must be tuned.
3) Clean the radiator surface.
4) Remove water from the feeder line.
5) Disable the second-trace echo rejector
referring to section 1.29.
1) Adjust the range with the control unit,
or the [RANGE] box several times. If
unsuccessful, replacement of keypad
may be required.
2) Replace SPU board.
3) Turn off and on radar.
Replace SPU board.
Replace SPU board.
1) Replace associated circuit board if un-
successful.
2) Replace MAIN board.