C387Main Circuit Operating Principle - Epson 2200 - Stylus Photo Color Inkjet Printer Service Manual

EPSON Stylus PHOTO 2100/2200

2.3.2 C387MAIN Circuit Operating Principle

The C387MAIN board consists of the logic circuits (CPU, ASIC, PROM, SDRAM,
1394 controller, USB2.0 controller), various motor control/drive circuits (CR motor,
PF motor, ASF/Pump motor), head control/drive circuit, interfaces (1284, USB, 1394,
USB2.0), sensor circuits, combination circuits (RTC, reset, EEPROM) and electrical
double-layer capacitor.
There are the following two great differences between the control circuits of this
product and conventional model.
!
Adoption of 3.3V/2.5V drive logic circuit components
The 3.3V/2.5V voltage is generated by the Regulator ICs (IC15, IC31) installed on
the C387MAIN board that reduces +5VDC generated by the C387PSB/PSE board,
and is used to drive multiple components. This is done to save power of the logic
circuit.
The following table indicates the 3.3V/2.5V drive components and 5V drive
components.
Table 2-16. 3.3V/2.5V and 5V Drive Components
+5V
• Linear encoders (CR, PF)
• Ink cartridge sensor
• Interface circuit
• Panel LED
• PE sensor
• ASF sensor
• Nozzle selection circuit (above Printhead)
• Cutter HP sensors (left, right)
!
Installation of hybrid circuit (IC9)
The hybrid circuit (IC9) installed consists of three different circuits, EEPROM,
RTC and reset.
By adoption of the large-capacity capacitor for timer, the Power-off timer can be
backed up for about one week after power-off.
OPERATING PRINCIPLES
3.3V/2.5V
• CPU
• P-ROM (SOJ)
• SDRAM
• Sensors (other than ink cartridge sensor,
PE sensor and ASF sensor)
• Interface circuit
• USB2.0 controller ASIC
• RTC, reset, EEPROM combination circuit
Electrical Circuitry Operating Principles
The following is the block diagram of the C387MAIN control board.
PROM
IEEE-1394
IC7
IC5
CN5
Address
CPU
CN2
IC29
Date
Cutter
USB 2.0
unit
IC2
CN20
Hybrid IC
IC9
CD-R
CN18
sensor
PE sensor
CN4
Parallel I/F
IC8
CN6
PG sensor
CN13
CN1
Release sensor
C387 PSB/PSE board CN15
Figure 2-19. C387MAIN Control Board Block Diagram
Revision B
SDRAM
IC6
Motor driver
CN17
IC24
Motor driver
ASIC
CN16
IC25
IC30
ASF/Pump motor
Motor driver
CN8
IC17
C387 panel board
CN14
PF encoder sensor
CN19
ASF sensor
CN12
CN11
Q6, Q7
IC27
Q9, Q10
CN10
CR encoder sensor
CR motor
PF motor
Head
68