REV.-A
2.2 POWER SUPPLY OPERATION
The printer can be powered by either of two power supply boards: the 120 V CO60 PSB board or the
V CO60 PSE board. The only difference between these boards is in the primary circuitry. The
ways in which they supply power to the printer are identical. These power supply boards output the
DC current necessary to drive the printer control circuits and the printer drive mechanism. Table 2-3
shows the input voltages and fuse ratings for these boards.
Table 2-3. Power Supply Boards
Board
Input Voltage
Fuse
Rating
CO60
PSB
103.5
to 132
125 V
CO60
PSE
198 to 264
250 V
2.2.1 Power Supply Overview
The power supply board has two power output lines that supply power to the various control circuits
and drive mechanisms. Table 2-4 lists the parts of the printer that run off these two DC output supply
voltages.
Table 2-4. Power Supply Output Voltages and Applications
Output Supply Voltage (DC)
Applications
v
Carriage motor drive
Paper advance motor drive
Printhead drive
v
CO60
MAIN board logic circuitry
Various sensors
Control panel
Paper advance
motor hold
2.2.2 Supply Circuit Operation
Figure 2-l 6 shows the power supply circuitry in block diagram form. AC power feeds into the printer
from the external power source. A filter circuit removes the noise. The AC voltage then undergoes full
wave rectification and is smoothed to produce the direct current supply voltage. This voltage is fed
through a switching circuit and secondary smoothing circuit to produce the stepped down
VDC
supply. A
V line voltage detector circuit is connected to the switching circuit. This feedback control
arrangement ensures that the
VDC supply remains stable.
The
VDC supply is achieved by feeding the
VDC line through the
VDC power supply circuit.
This circuit further steps down the
VDC voltage and outputs a stabilized
VDC supply.
There are four circuits to protect the supply circuitry and avoid danger. The
VDC line contains a
current overload protection circuit and a voltage overload protection circuit. The current overload
protection circuit is part of the + 5 VDC supply circuit. It cuts the + 5 VDC line if the current is too great.
The + 5 V voltage overload protection circuit cuts the supply if the voltage reaches or e 7 VDC.
It stops switching circuit operation, which stops the output of the
VDC line.
2 - 1 2
Summary of Contents for LQ-1170
Page 1: ...LQ 1170 24 PIN DOT MATRIX PRINTERS TM LQ8 1170 ...
Page 2: ...L Q 8 7 0 1 1 7 0 SERVICE MANUAL EPSON T Printed on recycled paper ...
Page 101: ...10 9 91 Yes NO Replace pluggable chips on main board 5 6 ...
Page 110: ...Table 5 4 Repair of the Power Supply Board Continued 5 15 ...
Page 118: ......
Page 121: ...REV A Figure 6 2 LQ 870 Lubrication Points 6 3 ...
Page 122: ...REV A Figure 6 3 LQ 1170 Lubrication Points 6 4 ...
Page 134: ...1 I II ...
Page 135: ...REV A Q m u D w IL 0 1 xl Figure A 3 CO60 DRV Board Circuit Diagram A 11 ...
Page 136: ...Figure A 4 CO60 PSB Board Circuit Diagram A 12 ...
Page 138: ...LO SLOE002 OWO9 1Nd 0 9 0 3 5 f l P I 11 I 01 I 6 I 8 1 L 9 I 9 I B I I2 I 2 I 1 ...
Page 142: ...REV A Fl 24ov T3 IsA I I II II AL I CU rl Figure A 10 C060 PSE Board Component Layout A 1 8 ...
Page 143: ...LMS d10 IP IMS dla ...
Page 144: ...REV A A 4 EXPLODED DIAGRAM Figure A l 2 1 Exploded Diagram for LQ 870 A 2 0 ...
Page 145: ......
Page 146: ...REV A Figure A 13 1 Exploded Diagram for Model 5DlO A 22 ...
Page 147: ... 5 2 5 610 c 3 5 9 0 El ...
Page 149: ...REV A A 5 CASE OUTLINE DRAWING Figure A l 4 1 Case Outline Drawing for LQ 870 A 25 ...
Page 151: ...lllllll IllI l l IIIIII II0 IIll III1 I I I C O 6 1 M A I N B o a r d A 3 7 ...
Page 152: ... U nRonenl2 i i C O 6 0 HAIN B t _1 m r OL J IIA IS I 19 CNI 36 I I8 I 23 IS ...
Page 153: ...a i iJ 0 E fig tfti I z ...