Furuno FR-1500 MARK-3 Series - Manual (Page 92)

-6.4-
Problem Probable causes or check
points Remedy
TUNE control adjusted but poor
sensitivity. 1 Deteriorated magnetron
1 Detuned MIC
3 Dirt on radiator face
4 Water ingress to the
waveguide or other
feeder line
5 Second trace rejection is
ON
1 With 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
below normal value, MIC may have
become detuned. MIC must be tuned.
3 Clean the radiator surface.
4 Remove water from the feeder line.
5 Disable the second-trace rejector
referring to section 1.31.
Range changed but radar
picture not changing. 1 Defective range key
2 SPU board
3 Mother board
4 Video freeze-up
1 Try to hit [+] and [-] range keys several
times. If unsuccessful, replacement of
keypad may be required.
2 Replace SPU board.
3 Replace mother board.
4 Turn off and on radar.
Interference rejector inoperable
(interference rejection level not
displayed) 1 Bad contact of key
2 SPU board
3 Mother board
1 Repair contact of key.
2 Replace SPU board.
3 Replace mother board.
Echo stretch ineffective (Neither
ES1 nor ES2 is displayed) 1 SPU board 1 Replace SPU board.
Only 2 parallel index lines when
6 lines are wanted. 1 Incorrect setting of index
line intervals
1 Set index line interval adequately
Range rings are not displayed. 1 Adjust the brilliance of
range rings at the BRILL
menu to see if intensity
is increased.
2 SPU board
1 Replace associated circuit board if
unsuccessful.
2 Replace SPU board.
(Continued on next page)