Epson MX-80 Technical Manual page 23

The AC 115. 220 or 240V from the power line first flows through fuse F1 (2A for 115V,
315 mA for 220/240V) and enters the double-throw power switch. Between this line and
ground, three noise suppressing capacitors 01. 02 and 03 are connected. The capaci
tors function to filter the line noise from the power source as well as the noise from the
printer to the power line, so that the digital circuits within Printer are not affected by
external noise and any noise from the Printer does not leak out to external lines.
(2) Power supply circuit
In this circuit, the AO 115. 220 or 240V from the primary side is lowered by the power
transformer to produce voltages required for the control circuit board, driver circuit
board and optional circuit board, respectively. Fig. 2.4 shows the windings and
input/output voltages of the power transformer
11 5V Brown
y 220V Yellow
'V. 240V Orange
(Primary)
OV O
V^nite
E o-
1 5 3V Blue
9V Gray
9 5V Red
23V Orange
Green/yel'o.v (fo' 11 5V only)
Fig. 2.4 Windings of Transformer
(Seconijary)
NOTE: The fourth pm (marked wiin
220/240V For 220V. insert tne
fifth pin (marked with •3")
•2") of the 5-pin connector on the primary side is used for selection of
yellow wire into tne fourth pm and the orange wire (240V) not used into the
The voltages lowered by the power transformer are converted into required voltages by
the rectifier and constant-voltage circuit. Fig. 2.5 shows the connection diagram of the
rectifier and constant-voltage circuit.
9 9 99 9
9 0
REV. A
-If -?
- ri —
HL
OMO* « ».• :
. .'— * ftj|» y
r i -
I
MO ^«
T«.
• 3-
ff
I
'z%Mcc.
o 1
— O /
J
.g
Fig. 2.5 Rectifier and Constant-Voltage Circuit
2-10
t j
11 \Ch4
ill