Functions Of Each Board - Furuno FELCOM 12 Service Manual

3.3 Functions of Each Board

Unit PCB Name
Helical ant.
DIPLEXER
Antenna
Unit
(IC-112)
ANT
TX
RF CON
Communi-
cation Unit
(IC-112)
CPU
REG
GPS
CPU CARD
VGA CARD
FDD
Terminal
Unit T. BOAED
(IB-581)
POWER
LCD
FIL
Keyboard
Printer
Disterss
IB-302
Alert Unit
Received
IB-303
Call Unit
I/F BOX OP16-14
EGC
PP-505
Printer
AC/DC
PR-300
PWR Unit
PCB Type
Consists of two pairs of antenna elements different in length,
-
generating a right circular polarization wave.
An isolation circuit between transmitting and receiving
signals. Its Isolation is:
• TX → RX: more than 40 dB,
-
• RX → TX: more than 40 dB.
The loss in the pass band is less than 1.0 dB.
Comprises L-band amplifier circuits for signal transmission
(1626.5 - 1646.5 MHz) and reception (1530.0 - 1545.0 MHz).
The operational input voltage is +29 V for transmission and
16P0146
+18 V for reception. The amplifier gain is:
• -5 dBm (input) → +43 dBm (output) for transmission, and
• +33
to
38 dB for reception.
Consists of a switching circuit between transmitting and
receiving signals, and a transmitting amplifier circuit (L
band).
16P0157
• Transmitting gain: +28 dB
• Receiving gain: -2 dB
Comprises a reference oscillator: VCXO (15.6 MHz),
transmitting/receiving synthesizer circuits, BPSK modulator,
and amplifier and frequency converter circuits for receiving
signals.
16P0147
• Receiving IF signal: 50 kHz, supplied to CPU board.
• Transmitting modulation signal: S-DATA is fed from CPU
board.
Consists of BPSK demodulation circuit, control circuit,
16P0148 transmitting/receiving signal processing circuits (by CPU),
and input/output interfaces.
Includes a switching regulator power supply circuit with a 24-
V input which supplies +5 V, +12 V, and a power switching
circuit; between +29 V in TX and +18 V in RX. ANT VOL
16P0149
detection circuit to detect short-circuits in ANT coaxial cable
and ANT CUR detection circuit to detect transmitting power
are also included.
GN-74 GPS receiver circuit
AR-B1374 Controls printer, keyboard, main unit, and memory.
AR-B1041 Controls LCD.
FD-235HF-
Controls floppy disk drive.
7529
Power supply circuit for VGA CARD - LCD relay and LCD
16P0141
illumination.
ACE-870C- Generates ±12 and ±5 V by a switching power circuit from
B1 +24-V input.
LCD
16P0144 A power line filter
BTC-5100C
A keyboard
PS/2
PP-510 Centronics specifications
Consists of a button-ON detector of distress alert unit, a lamp,
16P0150
and a buzzer.
Consists of a reception buzzer, a buzzer-OFF detector, and an
16P0150
indicator lamp.
A circuit for converting RS-232C to current loop for the
purpose of extending PP-505 cable
A printer exclusively used for EGC
An AC/DC automatic switching power supply
3-4
Function Remarks
Do not
adjust any
screws.
EE-PROM
(U11)
Having
FID/RID
Fan is on
during TX.
Optional
Optional
Two units
supplied
Optional
Optional
Optional