2.2 POWER SUPPLY OPERATION
The printer can be powered by either of two power supply boards: the C165 PSB (120 V) or C165 PSE (230
V) power supply. These boards are the same for both the LQ-2170 and FX-2170. Additionally, the PSB and
PSE boards function the same, except for a difference in primary circuitry. The power supply board outputs
the DC current necessary to drive the printer control circuits and drive mechanism. Table 2-5 shows the
input voltages and fuse ratings for these boards.
Table 2-5. Power Supply Board
Board
Input Voltage
Fuse F1 Rating
C165 PSB
103.5 to 132 VAC
6.3 A / 125 V
C165 PSE
198 to 264 VAC
T3.15 AH / 250 V
2.2.1 Power Supply Overview
The power supply board has two power outputs for use by the various control circuits and drive mechanisms.
Table 2-6 lists the applications for the two DC output supply voltages.
Table 2-6 Power Supply Output Voltages and Applications
Output Voltage (DC)
Applications
+5 V
Main Board Logic Circuit
Sensors
Control Panel LEDs
+35 V
CR Motor
PF Motor
Printhead Drive
Figure 2-22 shows a block diagram of the power supply circuitry.
As shown in the figure above, when AC power enters the printer from an external power source, the filter
circuit removes the noise. The AC voltage then undergoes full-wave rectification and is smoothed to produce
direct voltage. The voltage is fed to the gate port for the switching FET (Q1: K1531 or K1692) through
resistors R18 and R31, and then the switching circuit operates. The secondary smoothing circuit produces a
stepped down +35 VDC voltage. The +5 VDC voltage is generated by feeding the +35 VDC voltage through
the +5 VDC power supply circuit, where the +35 VDC is stepped down to a 5 VDC from the 35 VDC
line.
Filter Circuit
F u ll W a v e
Rectification
Circuit
Smoothing
Circuit
Switching
Circuit
AC input
Smoothing
Circuit
+5V Switching
Regurator
+5V Over current
Protection Circuit
+35V DC
+5V DC
Photo-
Coupler
Photo-
Coupler
+35V Line
Over Voltage
Protection Circuit
+35V Line
Over Load
Detector Circuit
+35V Line
Over Current
Protection Circuit
Operation
SW
Primary Circuit
Secondary Circuit
CPU
Port 20
+35V Line
Constant Voltage
Control Circuit
+5V Line
Over Voltage
Protection Circuit
+5V Constant Voltage
Control Circuit
Figure 2- 22 Power Supply Circuit Block Diagram
LQ-2170 Service Manual
Operating Principles
Rev.A
2-17
Summary of Contents for LQ-2170
Page 1: ...EPSON TERMINAL PRINTER LQ 2170 SERVICE MANUAL EPSON 4005735 ...
Page 5: ...REVISION SHEET Revision Issued Date Revision Page Rev A December 5 1995 1st issued ...
Page 11: ...Figure 1 1 Exterior View of the LQ 2170 Product Description LQ 2170 Service Manual 1 2 Rev A ...
Page 80: ......
Page 127: ...1 Abnormal CR Operation LQ 2170 Service Manual Troubleshooting Rev A 5 5 ...
Page 141: ...LQ 2170 Service Manual Troubleshooting Rev A 5 19 ...
Page 156: ...Appendix LQ 2170 Service Manual A 10 Rev A ...
Page 158: ...Appendix LQ 2170 Service Manual A 12 Rev A ...
Page 159: ...Figure A 3 C165 PSB Board Assembly Circuit Diagram LQ 2170 Service Manual Appendix Rev A A 13 ...
Page 160: ...Appendix LQ 2170 Service Manual A 14 Rev A ...
Page 161: ...Figure A 4 C165 PSE Board Assembly Circuit Diagram LQ 2170 Service Manual Appendix Rev A A 15 ...
Page 162: ...Appendix LQ 2170 Service Manual A 16 Rev A ...
Page 167: ...Figure A 9 LQ 2170 Exploded Diagrams 2 LQ 2170 Service Manual Appendix Rev A A 21 ...
Page 168: ...Figure A 10 LQ 2170 Exploded Diagrams 3 Appendix LQ 2170 Service Manual A 22 Rev A ...
Page 169: ...Figure A 11 C S F Bin1 Exploded Diagrams 1 LQ 2170 Service Manual Appendix Rev A A 23 ...
Page 170: ...Figure A 12 C S F Bin1 Exploded Diagrams 2 Appendix LQ 2170 Service Manual A 24 Rev A ...
Page 171: ...Figure A 13 C S F Bin2 Exploded Diagrams LQ 2170 Service Manual Appendix Rev A A 25 ...
Page 172: ...Table A 15 Part No Reference Table Appendix LQ 2170 Service Manual A 26 Rev A ...
Page 173: ...Table A 15 Part No Reerence Table Continue LQ 2170 Service Manual Appendix Rev A A 27 ...
Page 174: ...Appendix LQ 2170 Service Manual A 28 Rev A ...
Page 175: ...EPSON Printed in Japan 95 12 05 S ...