EPSON Stylus COLOR 880
Revision A
Operating Principles
Electrical Circuit Operating Principles
48
2.2.2.2 Reset Circuit
Reset circuits are attached on the C378MAIN board to monitor the two
voltages: +5V for the logic line and +42V for the drive line. When each circuit
detects abnormality on the corresponding line, it outputs a reset signal to reset
CPU and ASIC. This function is necessary to prevent the printer from operating
abnormally. IC5 RTC-9810SA, a reset circuit IC, is attached directly on the
main board. This IC monitors both the +5V and +45 lines but can reset them
independently. See Figure 2-18 for the block diagram for the reset circuits.
+5V line reset circuit
The VDD port of the IC5 reset IC monitors the +5V line. When the IC
detects an abnormal voltage level (4.3 V or lower), it outputs a reset signal
from the RST port to CPU and ASIC.
+42V line reset circuit
The VIN port of the IC5 reset IC monitors the +45V line. When the IC
detects an abnormal voltage level (35.5V or lower), it outputs a reset signal
from the VDT port to CPU and ASIC.
NOTE:
IC5, also serving as RIC (Real Time Clock), manages timer control when the
printer power is turned off. Power for this operation is supplied from the BAT1.
Figure 2-18. Reset Circuit Block Diagram
Summary of Contents for Stylus Color 880
Page 9: ...C H A P T E R 1 PRODUCTDESCRIPTION ...
Page 30: ...C H A P T E R 2 OPERATINGPRINCIPLES ...
Page 55: ...C H A P T E R 3 TROUBLESHOOTING ...
Page 76: ...C H A P T E R 4 DISASSEMBLYANDASSEMBLY ...
Page 116: ...C H A P T E R 5 ADJUSTMENT ...
Page 142: ...C H A P T E R 6 MAINTENANCE ...
Page 152: ...7 APPENDIX C H A P T E R ...
Page 177: ......
Page 178: ......
Page 179: ......