Electrical Circuit Operating Principles; C408 Pse Board - Epson Stylus Photo 895 Service Manual

EPSON Stylus PHOTO 895/785EPX

2.2 Electrical Circuit Operating Principles

The electric circuit of the Stylus PHOTO 895/785EPX consists of the following
boards.
Main board: C408 MAIN
Power supply board: C408 PSE
Monochrome panel board: C408 PNL
Printer panel board: C408 PNL-B
This section provides operating principles of C408 MAIN Board and C408 PSE Board.
Refer to Figure 2-17. "Electric Circuit" for the major connection of the each boards
and their roles.
C408 MAIN Board
Printon section
Printer section
+3.3VDC +5VDC +42VDC

C408 PSE Board

Figure 2-17. Electric Circuit
Operating Principles
Monochrome panel board
Printer panel board
Printer Mechanism
CR motor
PF motor
ASF motor
Head Driver Board
HP/PE Sensor
Electrical Circuit Operating Principles
2.2.1 C408 PSE board
The power supply boards of Stylus PHOTO 895/785EPX use a RCC (Ringing Chalk
Converter) circuit, which generates +42VDC for drive line and +5VDC, +3.3VDC for
logic line to drive the printer. The application of the output voltage is described below.
Table 2-7. Application of the DC Voltages
Voltage
• Motors (CR Motor, PF Motor, ASF motor)
+42VDC • Printhead common voltage
• Printhead nozzle selector 42V drive voltage
• C408 MAIN control circuit logic
+5VDC
• Sensor
+3.3VDC • C408 MAIN control circuit logic
AC voltage input from AC inlet first goes through filter circuit that removes high
frequency components and is then converted to DC voltage via the rectifier circuit and
the smoothing circuit. DC voltage is then lead to the switching circuit and FET Q1
preforms the switching operation. By the switching operation of the primary circuit,
+42VDC is generated and stabilized at the secondary circuit. This +42VDC generated
by the secondary circuit is converted to +5VDC, +3.3VDC by the chopping regulator
IC of the secondary circuit.
Revision A
Application
43