Furuno CH-270 Service Manual page 48

4) Transceiver Check
Unplug J5 on TRX board and connect the dummy
load (100 ohm, 30W) between TP6 and TP8.
Measure TX output signal between
TP6 and TP8 on TRX board.
Yes
OK?
No
Measure the TX output again.
OK?
No
(TX is faulty.)
Check the transmitter control
signals : TXO, TXI, TXV, and VTX.
OK?
Yes
Transmitter circuit on TRX
board is faulty.
Check the output signal from the
receiver at TP3 on TRX board.
OK?
No
Receiver circuit is faulty.
Yes
Slip-ring or Transducer
is faulty.
No
DSP board is faulty.
Yes
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