Epson DFX-8000 Service Manual page 81

2.3.2 Reset Circuit
Figure 2-16 shows a block diagram of the reset circuit.
The Vx circuit is the power-on reset circuit which generates the reset signal when the voltage becomes
unstable due to the printer power being turned on or off. The reset signal is input to the E05A1 6GA
gate array via the CPU, amplified, then supplied to the E05A38NA gate array and optional interface
to reset each IC.
The circuit monitors the + 12 V line using Zener diode ZD2, and the threshold voltage level is 4 V.
Transistor Q2 is turned on or off by ZD2.
+12 VDC Line Level
< 4
4 VDC <
Table 2-14. Power-On Reset Status
OFF
ON
FL 1
EMI
VX CIRCUIT
OPTION l/F
CN2
Figure 2-16. Reset Circuit Block Diagram
Vx output
GND (OV)
E05A16GA
RESET IN
~ -
RESET OUT
2-24
RESET signal
Low
High
CPU
I
RESET - T
p 3 4 4 - :
RESET