Furuno FR-2155, Service Manual

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2-4
2.3 Function of Each Board (Display Unit)
Board Name Function
SPU Board
03P9253
1) Contains a video amplitier circuit.
(a) Applies GAIN, STC, FTC and IR to video signal and outputs to the A/D converter.
(b) Adjusts video signal input level (adjusted by pot. VR140).
(c) Changes STC curve according to the antenna height set on the Radar menu.
(d) Echo Stretching 1.
2) Performs A/D conversion of video signal.
3) Echo averaging (EAV 1/2/3)
4) Constructs radar picture from HD, BP, TRIG, and VIDEO signals.
5) Controls
keyboard.
6) Mixes data being fed from ARP and RP boards to display them on the screen.
7) Displays navigation data being fed from a navigator.
8) Reads and displays trackball, EBL, and VRM data.
9) Controls tuning circuit.
10) Outputs “degauss” signal to the DEGAUSS Board.
11) Outputs Tx trigger and pulselength signals to the antenna unit.
12) Backs up menu settings, radar map, tune voltage, tune Ind. voltage, and waypoint
with the EEPROM (U10).
13) Echo Stretching 2/3.
14) Generates menus and radar maps.
15) Echo trailling.
16) Checks for the presence of ARP and RP boards at power-up.
ARP Board
18P9002
1) Compatible with latest ARP-23 hardware.
2) Converts GAIN-, STC-, FTC-, and I/R-processed video signal to quantized video
(QV) and sends back to the SPU Board.
3) Performs automatic and manual target acquisition and tracking.
4) Detects HD, BP, TRIG, VIDEO, LOG and GYRO signal errors.
5) Calculates CPA and TCPA.
6) Detects land echo.
7) Outputs ARPA data to the SPU Board : Target No., R/B, CPA, TCPA, etc.
8) Processes
trial maneuver.
RP Board
14P0298
1) Generates data (grid, own ship mark, mark, and ship's tracks, etc.) for the plotter
display.
2) Backs up data such as ship's tracks and marks.
3) Reads and displays digitized charts.
4) Outputs plotter display data to the SPU Board.
5) Inputs/outputs data (track, marks etc.) from/to the RAM card.
CARD I/F Board
14P0299
1) Receptacles of ROM and RAM cards.
2) Used to stores and retrieves data to/from ROM and RAM card.
INT Board
03P9252
1) Outputs HD, BP, TRIG and VIDEO signals to a radar slave display.
(J442/443, two output ports)
2) Receives HD, BP, TRIG and VIDEO signals from other radar. (J458)
3) Inputs/outputs RJ-7 signal. (J458/457)
4) Outputs ARPA data to the external equipment. (IEC-61162-2 , J454)
5) Outputs external buzzer signal. (J452)
6) Outputs V-SYNC, H-SYNC, R, G, B for a PC monitor or hard copier. A buffer circuit
required.
7) Inputs speed log signal, contact-closure. (J448)
8) Outputs alarm signals, Buffer board required.