Furuno FR-8125 ユーザーズマニュアル

6.  MAINTENANCE, TROUBLESHOOTING

This section describes how to cure hardware and software troubles which only quali-
fied service persons must do.

Power cannot be turned on. 1) Mains voltage/polarity

2) Power supply board

1) Correct the wiring and input 

voltage.

2) Replace the power board.

Brilliance adjusted but no 
picture.

1) SPU Board

1) Replace SPU Board.

Antenna not rotating.

1) Antenna drive mechanism

1) Replace the antenna drive 

mechanism.

Data and marks not dis-
played in transmit.

1) SPU board

1) Replace SPU board.

Set GAIN to the maximum 
with A/C SEA set at mini-
mum. Marks and indications 
appear but no noise or echo.

1) Signal between antenna and 

display unit

2) IF amplifier
3) Video amplifier board

1) Check continuity and isola-

tion of coaxial cable.

2) Replace IF amplifier.
3) Check coax line for fasten 

connection. If the connection 
is good, replace SPU board.

Marks, indications and noise 
appear but no echo. (Trans-
mission leak show your ship 
position is not present.)

1) Magnetron
2) Modulator board
3) SPU board

1) Check magnetron current.
2) Replace modulator board.
3) Replace the SPU board.

Picture not updated or pic-
ture freeze-up.

1) Bearing signal generator

2) SPU board
3) Video freeze-up

1) Make sure that the signal ca-

bles are fastened.

2) Replace the SPU board.
3) Turn the radar off, then on.

Radar is correctly tuned but 
sensitivity is weak.

1) [2nd Echo Rejector] is [ON]

2) Dirt on radiator face
3) Deteriorated magnetron

4) Detuned MIC

1) Turn off the [2nd Echo Rejec-

tor] from the [Echo] menu.

2) Clean the radiator.
3) Check the magnetron current 

with the radar transmitting on 
48 nm range. If the current is 
below normal, magnetron 
may be defective. Replace 
the magnetron.

4) Check the MIC detecting cur-

rent. If MIC detecting current 
is below normal value, the 
MIC may be detuned.

Range changed but picture 
does not change.

1) RANGE key has defaults

2) SPU board
3) Video freeze-up

1) Try to operate the RANGE 

key. If you can not operate 
the RANGE key, replace the 
keypad.

2) Replace the SPU board.
3) Turn the radar off, then on.

Range rings are not dis-
played.

1) Adjust their brilliance on the 

[Brill/Color] menu.

2) SPU board

1) Replace the associated cir-

cuit board if unsuccessful.

2) Replace the SPU board.