Service manual

EPSON Stylus Photo R280/R285/R290 Revision B
Chapter 2 Operating Principles 2.2 Electrical Circuit Operating Principles 24
2.2 Electrical Circuit Operating Principles
The electric circuits of the Stylus Photo R280/R285/R290 consist of the following
boards.
2.2.1 Main Features
The circuits support multi-common printing method that achieves high-speed printing
reducing the number of carriage movements.
! Features of C691Main Board
An EEPROM and a reset circuit are mounted individually to reduce the cost.
This is achieved by removing a complex RTC circuit that is mounted on the
previous model (R260/R265/R270/R360/R380/R390). Stylus Photo R280/
R285/R290 do not need the complex RTC circuit because a backup timer is
not required for them.
! Operations to reduce power consumption
The printer carries out the following operations to go into sleep mode.
Decreases the power voltage.
Shuts off photoelectric current of photo interrupter sensors.
Stops the motor drive circuit.
Stops some part of the clock in the ASIC.
De-energizes the motors.
Makes the head drive circuit go into standby state.
2.2.2 Components of Control Boards
Table 2-4. Main Boards & Model Numbers
Board Name R280/R285/R290
Main Board
C691MAIN
Power Supply Board
C691PSB
Panel Board
C691PNL
Table 2-5. Components of Control Boards
Board Name Incorporated Components
Main
Board
System
! Logic circuit
(SOC incorporated in the CPU core, Flash ROM (4 Mbit) x 1, SDRAM x 1,
Local SDRAM controller, Local SDRAM (64 Mbit)
! SSCG circuit
! Panel I/F
! Regulator
! Power saver
! Oscillator circuit
! Power control circuit (PSC/ESAVE)
! Reset circuit
! USB interface
! EEPROM
Printer
! Motor drive circuit (PF, CR)
! Printhead drive circuit
! CSIC/IF
! Sensor circuits
Panel Board
! Power switch read-in circuit
! LED driving circuit