Countermeasures Against Failures; Power Can Not Be Turned On - Furuno DSC-60 Service Manual

2. Countermeasures against Failures

2.1 Power can not be turned on.

Refer to Page 2-11.
- Check the polarity of the power supply.
- Check to be sure that the power supply voltage is the rated value: 21V to 31V. (The over-
voltage protection circuit works at 35V, and the power can not be turned on.)
NO
Adjust input voltage check
note)
Abnormal current flows on 24V line and
polyswitch of FL1, 2 of LINE FIL board work.
Exchange SW REG board.
*Exchange SW REG board.
Over-voltage detection circuit of Q4 to Q6, VR3,
and VR4 is in failure.
*Exchange PANEL board.
Power switch circuit of Q1 and S21 is in failure.
Note) Polyswitch Note) Polyswitch
Note) Polyswitch Note) Polyswitch Note) Polyswitch
For example, if Q1 on SW REG board is in failure and an abnormal current of more than 4 A flows on
24V line, the temperatures of polyswitches F1 and F2 on LINE FIL (05P0707) of the rise and the 24V
line is cut off. To reset the polyswitch, its temperature must be lowered. It takes a few minutes before the
temperature is lowered.
Power can not be
turned on.
Power is supplied to the main unit?
(Rated voltage: 21 to 31V)
Note) If the voltage is over 35V, the protection
circuit works and power can not be turned on.
NO 24V are supplied to
SW REG board?
(J1-#1: 24V, J1-#2: 24V)
POWER ON signal (24V) outputs from
NO
between J2-#3 and J2-#7, #8 on SW REG
board when power is turned on?
Specify the faulty board by pulling out each
connector one by one.
*AF board: J5
2. Countermeasures against Various Failures
Power plug
#2.24V-
YES
NO
SW REG outputs +15V ?
YES
No display appears.
Check the connection between
CONTROL/MODE and PANEL boards.
Is the over-current protection circuit operating?
1. Pull out SW REG output pins: J2-#5, #6 (+15V).
2. Check that 15V outputs between
J2-#5, -#6 (15V) and J2-#7, #8 (GND).
15V: Yes
*Both RX boards: J2
7-7
#1.24V+
YES
YES
15V: No
Exchange
SW REG board.