Circuit Description - Sony RM-B150 Maintenance Manual

2-3. Circuit Description

CPU-266 board
The CPU-266 board is a main control board, and consists of the following circuits.
. IC2 (Main CPU):
Main control
LED character display interface
Buzzer control
. IC18 (Sub CPU): Panel interface control
. X2:
Clock
. IC4: Program ROM
. IC5:
SRAM
. IC12:
EEPROM (storing the setting values)
. IC13: NVRAM (storing the special setting values)
. IC15:
Rotary encoder controller
. IC11: Command interface
The sub CPU controls input signals from the switches and adjustment controls on the control panel and
menu panel. It also controls output signals to the LEDs on the control panel. The I/O port that is needed
to control the LED character display and buzzer circuit is controlled by the PIO port in the main CPU.
SW-962 board
The SW-962 board is equipped with the switches and LEDs on the control panel, and consists of the
switch scanning decoders and LED drivers. They are controlled by the sub CPU (IC18) on the CPU-266
board.
VA-186 board
The VA-186 board consists of the cable compensation circuit for the video signals and power circuits.
The cable compensation circuit can compensate for the three different kinds of cables in length 10 m,
50 m and 100 m. Cable compensation length can be selected using the menu.
The power circuits consists of the switching regulator and series regulators. They generates the following
voltages from the DC input of 10.5-30 volts externally supplied.
. +5 V for logic circuit
. +5 V for analog-to-digital conversion circuit (for adjustment controls on the control panel)
. +5 V for video (cable compensation) circuit
. +5.5 V for LED drivers
First, +5.5 V is generated by the switching regulator and then is supplied to the LED drivers. On the other
hand, three kinds of +5 V is generated from this +5.5 V by the series regulators and are
supplied to the logic, analog-to-digital conversion and video circuits respectively.
SW-963 board
The SW-963 board is equipped with the switches and rotary encoder (MENU SELECT knob) on the
menu panel. They are controlled by the sub CPU (IC18) on the CPU-266 board via the VA-186 board.
LED-317 board
The LED-317 board is equipped with the LED character display, that is controlled by the main CPU
(IC2) on the CPU-266 board.
CN-1651 board
The CN-1651 board is equipped with the REMOTE connector and BNC connector for monitoring.
RM-B150
2-3. Circuit Description
2-3(E)