Furuno CH-270, Service Manual

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41
Operate the sonar in self-check mode where the
display unit alternately drives the tilt/train circuits.
Which is faulty, tilt or train?
Tilt problem
Train problem
Check tilt motor drive pulse on DRV board
06P0154.
01 : Q5 (C)
02 : Q3 (C)
03 : Q4 (C)
04 : Q2 (C)
Common is (-) of
ship’s supply.
+8ms
V
0V
Note that train and tilt circuits
are driven alternately.
Check result is OK?
No (Driver circuit has problem.)
Check TI CLK and TI DN/UP input signal on
DRV board 06P0154.
TI CLK : U7 #12 J1 #20 (com)
TI DN/UP : U7 #6
J1 #20 (com)
TI CLK
TI U/D
UP : 0V
DN : t4.5V
+4.5V
0V
2ms
Check wiring between the transceiver unit
and the hull unit.
U3 or Q2/Q3/Q4/Q5 is faulty.
Drive circuit is OK.
(Tilt Motor or Feedback Circuit is faulty.)
Check result is OK?
Yes
No
Yes