3. +35 V Constant Voltage Control Circuit
The +35 V constant voltage control circuit is illustrated below.
The constant voltage control circuit operates to keep the 35 V line at 35 V
±
6 %. When the voltage between
ZD51 and ZD85 becomes 32.7 V
±
2.75 %, PC1 turns on, and then Q2 also turns on. Consequently, switching
FET Q1 shuts off. When the voltage between ZD51 and ZD85 becomes less than 32.7
±
2.75 V, PC1 turns
off, and then Q2 also turns off. Consequently, switching FET Q1 operates again. Repeating the above
operation keeps the +35 V line at 35 V
±
6%.
4. +35V Line Overload Detection Circuit
The +35 V line voltage drop protection circuit is shown in the figure below.
When the +35 V line is overloaded, it means that constant voltage control is not being maintained. In this
condition, the forward current of PC1 drops to 0 A. Consequently, voltage Vf between PC1 and D81 also
drops. On this circuit, when the Vf voltage drops below 1.3 V (+35 V line: 33.1 V), IC528 detects the
overload and outputs the PWDN signal (+5 V: HIGH active) to port 20 of the CPU. When the CPU receives
this PWDN signal, printing stops. When the +35 V line becomes normal again, the voltage between PC1 and
D81 also becomes normal. When the Vf voltage goes above 1.6 V (+35 V line: 33.4 V), the PWDN signal is
removed.
+35V Line
ZD81
ZD51
ZD82
ZD83
ZD84
ZD85
D81
R56
R57
GND Line
9+
10+
11
R11
C13
Q3
R14
C12
+
Q1
1
2
8
7
R20
R21
R19
C15
Q2
R13
R15
R16
IC1
Figure 2-25 +35 V Line Constant Voltage Control Circuit
+35V Line
ZD81
ZD51
ZD82
ZD83
ZD84
ZD85
D81
R56
R57
GND Line
1
2
8
7
PWDN
+5V Line
GND
R87
R86
R83
R84
+
-
7
8
4
6
5
PC1
Q31
R20
Figure 2-26 +35 V Line Overload Detection Circuit
FX-2170 Service Manual
Operating Principles
Rev.A
2-19
Содержание FX-2170 - Impact Printer
Страница 1: ...EPSON TERMINAL PRINTER FX 2170 SERVICE MANUAL EPSON 4005662 ...
Страница 5: ...REVISION SHEET Revision Issued Date Revision Page Rev A October 13 1995 1st issued ...
Страница 11: ...Figure 1 1 Exterior View of the FX 2170 Product Description FX 2170 Service Manual 1 2 Rev A ...
Страница 140: ...FX 2170 Service Manual Troubleshooting Rev A 5 19 ...
Страница 142: ......
Страница 156: ...Appendix FX 2170 Service Manual A 10 Rev A ...
Страница 157: ...A 4 CIRCUIT DIAGRAMS Figure A 2 C166 MAIN Board Assembly Circuit Diagram FX 2170 Service Manual Appendix Rev A A 11 ...
Страница 158: ...Appendix FX 2170 Service Manual A 12 Rev A ...
Страница 159: ...Figure A 3 C166 PSB Board Assembly Circuit Diagram FX 2170 Service Manual Appendix Rev A A 13 ...
Страница 160: ...Appendix FX 2170 Service Manual A 14 Rev A ...
Страница 161: ...Figure A 4 C166 PSE Board Assembly Circuit Diagram FX 2170 Service Manual Appendix Rev A A 15 ...
Страница 162: ...Appendix FX 2170 Service Manual A 16 Rev A ...
Страница 164: ...Figure A 6 C166 PSB Board Assembly Component Layout Appendix FX 2170 Service Manual A 18 Rev A ...
Страница 165: ...Figure A 7 C166 PSE Board Assembly Component Layout FX 2170 Service Manual Appendix Rev A A 19 ...
Страница 166: ...A 6 EXPLODED DIAGRAMS Figure A 8 FX 2170 Exploded Diagrams 1 Appendix FX 2170 Service Manual A 20 Rev A ...
Страница 167: ...Figure A 9 FX 2170 Exploded Diagrams 2 FX 2170 Service Manual Appendix Rev A A 21 ...
Страница 168: ...Figure A 10 FX 2170 Exploded Diagrams 3 Appendix FX 2170 Service Manual A 22 Rev A ...
Страница 169: ...Figure A 11 C S F Bin1 Exploded Diagrams 1 FX 2170 Service Manual Appendix Rev A A 23 ...
Страница 170: ...Figure A 12 C S F Bin1 Exploded Diagrams 2 Appendix FX 2170 Service Manual A 24 Rev A ...
Страница 171: ...Figure A 13 C S F Bin2 Exploded Diagrams FX 2170 Service Manual Appendix Rev A A 25 ...
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Страница 174: ...EPSON ...