Epson 2080 - LQ B/W Dot-matrix Printer, Руководство по обслуживанию

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LQ-2080 Revision A
Operating Principles Control Circuit 25
2.3.1 System Reset Circuit
Control circuits IC3 and IC4 are initialized when a /RESET signal (LOW
level) is output from port 1 (VOUT) of IC2. IC2 monitors the +5 V line on
port 3, and resets under the following conditions:
1. When the power supply is turned on, a /RESET signal is output.
/RESET is canceled when the +5 V line goes up to 4.2 V, and then
100 ms passes.
2. When the +5 V line goes below +4.2 V, a /RESET signal is output.
/RESET is canceled when the +5 V line goes back up to 4.2 V and
then 100 ms passes.
Figure 2-3. Reset Circuit
Figure 2-4. Reset Signal Output Timing
V O U T
M R E S
V C C
G N D
+ 5 V
+ 5 V
R 6 3
1 K
I C 2
P S T 5 9 2 0
C 3 6
0 . 1 U
I C 4
I C 3 E 0 5 B 2 4 Y A
T P M 9 6 C 0 4 1 A F
2 3 R E S E T
7 4
R E S E T
1
2
3
4
1
2
3
4
5
V C C ( + 5 V l i n e ) V O U T ( R E S E T )
R E S E T
R E S E T
P o w e r O n
( v )
1 0 0 m s
1 0 0 m s