Power Supply Circuit; Power Supply Overview - Epson fx-2180 Service Manual

FX-2180 Service Manual

2.1.2 Power Supply Circuit

This printer can be powered between three power supply boards: the
C166PSB(120V), C166PSE(220-240V) and C244PSH(120V/220-240V).
The function of these boards s the same, except for a different in a primary
circuit. The input voltages and fuse ratings for these boards are shown
below;
Table 2-1. Power Supply Board
Board Input Voltage
C166PSB 103.5 - 132V
C166PSE 198 - 264V
C244PSH 85 - 138V / 187 - 276V

2.1.2.1 Power Supply Overview

The power supply board has two DC power outputs for control circuit and
printer mechanism. These power outputs are listed on following table;
Table 2-2. Power Supply Outputs Applications
Output Voltage
• Control Circuit board Logic
+5VDC
• Detectors
• Operation Panel LEDs
• CR Motor
+35VDC
• PF Motor
• Printhead
The block diagram of power supply circuit is shown following figure. When
AC power enters the printer from external power source, the filter circuit
removes the noise. Then AC voltage undergoes full-wave rectification and
smoothed to produce direct voltage. But, in case of C244PSH board, the AC
voltages undergoes the voltage doubler rectification automatic switching IC
and smoothed to produce direct voltage. The voltage is fed to the gate port
for the switching FET (Q1)through resistors (R18 and R31), and then the
switching circuit operates.
The secondary smoothing circuit produces a stepped down +35VDC
voltage. The +5VDC is generated and stabled by feeding the +35VDC
voltage through the +5VDC power supply circuit IC. As this power supply
Rev. A
Fuse F1 Rating
3.15A / 125V
T2.0AH / 250V
5HT4
Applications
circuit composed of an ZC-RCC (zero cross ringing choke converter), it
realizes to the circuit high stability, efficiency and portability.
This circuit provides the power switch (operate switch) in the secondary
circuit system. The operate switch on the operation panel controls the power
supply circuit.
There is +35v line constant voltage control circuit and over current / voltage
circuits in order to protect the printer and control circuit.
Figure 2-2. Power Supply Circuit Block Diagram
Operating Principles
2-2