Block Description Of Dc Power Board (03P9338) - Furuno FAR-2107 Series Service Manual

1. Turning on the antenna
ANT ON signals inputted from the SPU board control the switching power supply
IC of U161 via the "ANT Soft Start" circuit comprised of Q153 and C157.
2. Maintaining the antenna speed constant
To maintain the antenna speed constant, there is a feed-back circuit provided. In
this circuit, the number of revolutions (F) of B.P signals from the antenna is
converted into voltage (V) at U162. These signals control U161 and change the
switching power supply output voltage to maintain the antenna speed constant.

4. Block description of DC power board (03P9338)

The DC power board has no circuit corresponding to the input part of the AC power
supply. Other features of the switching power supply circuit are the same as for the AC
power supply. The HIC of U11 incorporates IC (MB3771PF) for monitoring power
supply. If the input is out of the range between the input over voltage 35 VDC and input
low voltage 15 VDC, the power supply is not turned on by controlling "DT Cont., Soft
Start" circuit for the switching power supply of +24 VDC, +12 VDC, -14 VDC and +32
VDC.
5. Power-on of monitor unit (MU-201CR, MU-231CR)
The signal for starting the power supply to the monitor unit is the signal of #14 pin (+5
V POWER) of DVI connector.
The figure below shows the schematic diagram of this line.
PWR board
Fig. 7.3.26 Schematic diagram of monitor unit power supply control
SPU board
J104-
#4/5/6(+5V)
J201-
#4/5/6(+5V)
7-68
DVI-D
DVI-D
Vcc
J204-#14(+5V)
DVI-D
J205-#14(+5V)
7.3 Processor Unit: RPU-013
MONITOR
(MU-201CR)
(MU-231CR)
Ship's Main
(AC or DC)