Figure; Reset Circuit - Epson LQ-860 Technical Manual

2.3.1 Reset Circuit

Figure 2-24 shows the reset circuit.
After being input to the E05AIOAA gate array (MMU :8B), the reset signal resets the gate array, then is sent
out to the other devices. Reset operation (hardware reset) is performed when:
The printer power is turned on or off.
A identity/font module is installed or removed with the power on.
2.3.1.1 Vx (Drive System Pull-up) Voltage Supply Circuit
Figure 2-25 shows the Vx voltage supply circ:uit.
The Vx voltage is used to pull up the bus for the control signals transmitted to the power on reset circuit
and drive circuits.
After the printer power is turned on, the -t35 V line reaches about 27.7 V, and then Q5 and Q48 are turned
on so that current iG flows from the +5 V line to the Vx line. Therefore, +5 V is applied to the Vx line.
If the +35 V line drops below 27.7 V, Q5 and Q48 are turned off so that the Vx line drops to O V. The IC
is threfore reset and the printer stops printing.

Figure 2-24.

+5
Figure 2-25. Vx Voltage Supply Circuit
2-29
Reset Circuit
t
GP
CPU (46)
JUNMM
BOARD
of E05A24GA
(116)
EXTERNAL
RESET
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