Furuno FR-7041R-MARK-2 Operator's Manual page 57

Problem
STBY TX pressed to transmit but...
• On the Installation Setup 1
antenna does not
rotate
• Antenna drive gears.
• Antenna motor power circuit.
• Antenna motor B801.
Sensitivity adjusted with A/C RAIN and A/C SEA off but...
• IF AMP board.
neither noise nor
targets appear
• Antenna cable.
(indications do)
• SPU board.
• SPU board.
neither
indications nor
• Short in trigger line of signal
markers appear
(noise and
• Measure magnetron heater
targets do)
• Modulator circuit.
• Bearing pulse generator circuit
sweep is not
synchronized
with antenna
• SPU board.
rotation
• Measure magnetron voltage as
sensitivity is poor
• MIC may have detuned.
Key is pressed but...
• Keyboard may be faulty.
no response
• SPU board.
Table 3-3 Advanced troubleshooting (con't.)
Check point
menu, confirm that "Ant on Tx"
is set to "Rotate."
cable.
voltage.
in antenna unit.
prescribed above.
3. MAINTENANCE, TROUBLESHOOTING
Remedy
How to measure magnetron heater
voltage:
1. Turn on the radar and leave it in
stand-by.
2. Open the antenna cover.
3. Unfasten screws to remove the RTB
cover.
4. Connect a multimeter, set to 10 VDC
range, between test point J825#4
and J825#6 (GND) on the RTB Board
(03P9249).
5. Confirm the meter reads 7.6 V
±0.1V.
6. Close the RTB cover.
7. Close the antenna cover and tighten
the cover fixing screws.
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