Epson 2200 Service Manual - Page 68

EPSON Stylus PHOTO 2100/2200 Revision B 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) 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 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. The following is the block diagram of the C387MAIN control board. IEEE-1394 CN5 IC7 CN2 Cutter unit CPU IC29 USB 2.0 CN20 Hybrid IC IC9 PE sensor CD-R sensor Parallel I/F CN6 PG sensor Release sensor PROM IC5 Address Date SDRAM IC6 Motor driver IC24 IC2 ASIC Motor driver IC30 IC25 CR motor CN17 PF motor CN16 ASF/Pump motor CN18 CN4 IC8 Motor driver IC17 CN8 CN14 CN19 C387 panel board PF encoder sensor ASF sensor CN13 CN1 CN12 IC27 Q6, Q7 Q9, Q10 CN11 CN10 CR encoder sensor Head C387 PSB/PSE board CN15 Figure 2-19. C387MAIN Control Board Block Diagram OPERATING PRINCIPLES Electrical Circuitry Operating Principles 68