Reset Circuit; Detection Circuit - Epson SQ-1170 Service Manual

2.3.2 Reset Circuit

When the power in turned on, the reset IC(MB3771 ), which monitors the + 5 VDC line, keeps outputting
RESET signals until +5 VDC is stable. This controller can also reset itself by setting RSTRG signal(160
pin of E05A65 gate array) to LOW. The block diagram of this circuit is shown in Figure 2-39.

2.3.3 Detection Circuit

This printer is provided with 1 sensors, but only 7 sensors are described in this section. They are Ink
Cartridge Sensor, Ink End Sensor, Platen Gap Sensor, Friction/Tractor Select Sensor, Top Edge Sensor,
Paper End Sensor (Front), and Paper End Sensor (Rear). The signals from these sensors are directly
inputted to the CPU port.
For the other sensors, refer to each circuit as follows.
Ink temperature detector (Thermistor)
+ 35VDC under voltage detection circuit---EEPROM control circuit
Case open sensor (interlock switch)
Encoder
GA
A
160
Figure 2-39. Reset Circuit Block Diagram
---Head drive circuit
---Head drive circuit /Carriage
---Carriage motor drive circuit
IE2
GAP
EDGE
PE
PE(Rear)
Figure 3-40. Detection Circuit Block Diagram
MB3771
IC21
6 8
CPU
2-31
RESET
motor drive circuit
REV.-A