7. +5 V Line Constant Voltage Control Circuit
The +5 V line constant voltage control circuit is shown below.
Port 16 of IC51 (TL494CN) monitors the + 5 V line, and the voltage is compared with the standard voltage,
which is input into port 15. When the voltage of port 16 goes below 4.81 V or above 5.17 V, the pulse width
of the PWM signal, which is output from port 8, changes and the +5 V line is kept between 4.81 V to 5.17 V.
+5v Line
G N D
R 5 3
R88
R64
R 6 5
+
IC51
TL494CN
D51
L51
8
R51
R61
Q51
-
16
15
+35V
R81
R59
R60
ZD55
GND
GND
Figure 2-29 +5 V Line Constant Voltage Control Circuit
LQ-2070 Service Manual
Operating Principles
Rev.A
2-21
Summary of Contents for 2070 - LQ B/W Dot-matrix Printer
Page 1: ...EPSON TERMINAL PRINTER LQ 2070 SERVICE MANUAL EPSON 4006244 ...
Page 5: ...REVISION SHEET Revision Issued Date Revision Page Rev A April 8 1996 1st issued ...
Page 11: ...Product Description LQ 2070 Service Manual Figure 1 1 Exterior View of the LQ 2070 1 2 Rev A ...
Page 55: ...LQ 2070 Service Manual Operating Principles Rev A 2 7 ...
Page 58: ...Operation Principles LQ 2070 Servcie Manual 2 10 Rev A ...
Page 63: ...Down LQ 2070 Service Manual Operating Principles Rev A 2 15 ...
Page 112: ...Disassembly and Assembly LQ 2070 Service Manual 3 34 Rev A ...
Page 146: ...Maintenance LQ 2070 Service Manual 6 4 Rev A ...
Page 165: ...EPSON ...