Troubleshooting - Furuno FS-1503 Service Manual

5.3 Troubleshooting

Symptom
No power being
1
supplied
Power is shut
2
down.
3 LCD blinks.
Nothing on LCD
4
display
LCD display is
5 freezed, or
abnormal.
6 No key response
7 TUNE error
Table 5-1 Troubleshooting Guide List
Possible Cause/Test
1 Brown in-line fuse (30A).
2 Overvoltage protector (17 V) activated.
Defective power switch. Disconnect power
connector, check between J1 #1 and #2 on
3
PA/FIL board for continuity.
Defective SW REG board (optional).
Measure voltage between J2 #1 and #3 for
4
12 V (input), and between J3 #1 and #3 for
12 V (output).
When getting into TX mode. Defective
1 relay K1. Breaker F2 on PA/FIL board
trips.
2 Defective PA Transistor.
3 When connecting BK line.
UNLOCK signal is detected; defective
1
PLL.
If 12 V is supplied to PA, F1 (4A) on
1
PA/FIL board trips.
Loose connection on PCB. Defective flat
1
cable on CPU board.
Specific key does not work. (Carry out
1
self-test.)
All keys do not work. CR1 on CPU board
2
does not blink.
1 Carry out self-test.
If TUNE error appears immediately after
2
TX, no RF signal is input to antenna cou-
pler.
If antenna coupler does not start tuning,
3
control circuit is defective.
If TUNE error occurs on specific band,
4
antenna and/or grounding is abnormal.
If tuning is unstable on specific band, an-
tenna and/or grounding is abnormal, or
5
matching relay in antenna coupler is de-
fective.
If frequency range in which TUNE error
6 occurs is the same as that of a TX filter,
TX FIL circuit is defective.
5-6
Remedy
Replace fuse.
Check power supply for
13.6 V ± 15 %.
Replace switch.
If no input, replace PA/FIL
board. If no output, replace
SW REG board.
Replace PA/FIL board.
Replace PA Transistor, or
PA/FIL board.
Check BK lines for correct
wiring.
Replace TX/RX board.
Check J2 (12 V line) on
PA/FIL board for overload.
Check connections. Replace
CPU board.
Replace CPU board.
If cannot, replace COUP
board.
⋅ Check coaxial cable between
main unit and antenna cou-
pler for discontinuity.
⋅ Check transmitter circuit in
main unit.
⋅ Check TUNE power data for
40 (standard).
⋅ Check system setting 9920.
⋅ Check control signal lines
connected between main unit
and antenna coupler
Check antenna and ground
wire connection. If OK, try to
change antenna length.
⋅ Check antenna and ground
wire connection. If OK, try
to change antenna length.
⋅ Replace COUP board.
Replace PA/FIL board.