Furuno FS-1570, Service Manual

Page: 120 / 322

5.1 Configuration
5-3
5.1.2 Boards in Transceiver unit
Table 5.1.1 lists the function of each board in the transceiver unit.
Table 5.1.1 Boards in Transceiver unit
Board Type Function Remarks
T-CPU 05P0732
1) Consisting of Main CPU, SUB CPU-1 (I/F), SUB
CPU-2 (I/F) and associated circuits.
The DIP switches on this board are set depending on
system configuration.
DSP
(For DSC)
05P0751
1) Consisting of DSP, Modem and Flash ROM.
2) DSC program is stored in Flash ROM.
3) The serial communication is made between the
DSC DSP and Main CPU.
DSP
(For NBDP)
05P0751
1) Consisting of DSP, Modem and Flash ROM
2) NBDP program is stored in Flash ROM.
3) NBDP DSP communicates with Main CPU in
parallel.
TX/RX 05P0733
1) Consisting of modulator and demodulator for
DSC, NBDP and VOICE signals, and local
oscillators.
AF input/output signal: 600
Ω
/ -10 dBm
Output power: 0.5 W
The board outputs S, RXAF, TXAF and TXOUT (RF)
signals to T-CPU board for checking.
PRESEL 05P0746
1) Consisting of 5 filters.
2) 1.45 to 4.99 MHz filter consists of tuning circuits.
An adequate capacitor is selected by a relay for
the selected frequency. Other four filters is a band
pass filter.
REF OSC 05P0747
1) This board is a 18 MHz reference oscillator.
2) The output is sent to T/R, W/R1 and W/R2
boards. When the transceiver unit is supplied 24V,
+12 V (oven voltage) is supplied to the oven.
TEMP signal is output to T-CPU board. If the TEMP
signal is lower than the designed value, the
transceiver does not transmit.
W/R1 05P0734
1) This board is a DSC distress safety receiver,
consisting of RF amplifier, a demodulator, an AF
amplifier and local oscillators.
2) The board uses 18 MHz reference signal from
REF OSC board. For self test, 18 MHz signal is
applied to the antenna circuit (RF connection).
3) The T-CPU identifies W/R board with INST signal.
W/R1 board is identical to W/R2 board.
FS-1570T/
2570T
PA 05P0739
1) Two stage push-pull amplifier outputs 150 W
signal. power gain: 27 dB
2) Check signal output to T-CPU: TEMP, VC and IC
FS-1570T