EPSON FX-2180 Service Manual Chapter 2 Operating Principles
2-2
2.1.2 Power Supply Circuit
The printer can be powered by one of the following three power supply
boards: C166 PSB (120 V), C166 PSE (220 – 240 V), or C244 PSH
(120 V / 220 – 240 V). The boards function in the same way, except each
board has a different primary circuit. The table below lists the input
voltages and fuse ratings of the boards.
Table 2-1. Power Supply Board
Board Input Voltage Fuse F1 Rating
C166 PSB 103.5 – 132 V 3.15 A / 125 V
C166 PSE 198 – 264 V T 2.0 AH / 250 V
C244 PSH 85 – 138 V / 187 – 276 V 5HT4
2.1.2.1 Power Supply Circuit Operation
The power supply board has two DC power outputs: one for the control
circuit and one for the printer mechanism. The table below lists the
applications of the output voltages.
Table 2-2. Power Supply Output Applications
Output Voltage Applications
+5 VDC • Control circuit board logic
• Sensors
• Control panel LEDs
+35 VDC
• CR motor
• PF motor
• Print head
When AC power enters the printer from an external power source, the filter
circuit removes the noise. Then the AC voltage undergoes full-wave
rectification and is smoothed to produce direct voltage. In the C244 PSH
board, the AC voltages undergo voltage doubler rectification in the
automatic switching IC and are smoothed to produce direct voltage. The
voltage is fed to the gate port for switching FET Q1 through resistors R18
and R31. Then the switching circuit operates.
The secondary smoothing circuit produces a stepped down +35 VDC
voltage. The +5 VDC voltage is generated and stabilized by feeding the
+35 VDC voltage through the +5 VDC power supply circuit. The power
supply circuit includes a ZC-RCC (zero cross-ringing choke converter),
which contributes to the power supply circuit’s high stability, efficiency, and
portability.
The secondary circuit system of the power supply circuit includes the
Operate
(power) button. The
Operate
button is located on the printer’s
control panel and controls the power supply circuit.
A +35 V line constant voltage control circuit and over-current/over-voltage
protection circuits are provided to protect the printer and control circuits.
