Service manual

Chapter 2
Principles of Operation
Overview
......................................................................................... 2-1
Connector Summary
..................................................................
2-1
-
Overview of Printer Mechanism Operation
..............................
2-3
Sensors
.................................................................................
2-4
Motors
..................................................................................
2-6
Printhead
.............................................................................
2-6
Circuit Overview
........................................................................
2-7
Firmware Overview
...................................................................
2-8
Principles of Operation
....................................................................
2-9
Power Supply
Circuit
.................................................................
2-9
Power supply circuit block diagram
....................................
2-9
Chopper-type switching regulator circuit
............................
2-11
Filter circuit
.........................................................................
2-13
Transformer
.........................................................................
2-14
Rectifier and smoothing circuit
...........................................
2-15
+5 VDC regulator circuit
....................................................
2-16
pulse width modulation circuit
...........................................
2-19
+24 VDC regulator circuit
..................................................
2-21
Vx voltage supply circuit
.....................................................
2-24
Reset Circuit
..............................................................................
2-25
Power on or off
.....................................................................
2-26
-INIT signal input from CN1
..............................................
2-26
ROM cartridge installation and removal
............................
2-27
Address Decoder and Bank Register
.........................................
2-29
Address decoder
....................................................................
2-29
Bank register
.......................................................................
2-29
Carriage Operation
...................................................................
2-30
Carriage
mechanism
...........................................................
2-30
Carriage motor drive circuit block diagram
.......................
2-31
Gate array E0lA05 in the carriage motor
drive circuit
....................................................................
2-32
Carriage motor drive circuit
................................................
2-33
Carriage motor software control
..........................................
2-38
Paper Feeding
...........................................................................
2-43
Paper feed mechanism
........................................................
2-43
Paper feed motor drive circuit
.............................................
2-45
Paper feed motor software control
.......................................
2-46
Printhead
...................................................................................
2-47
Printing...............................................................................
2-47
Printhead drive circuit block
diagram
.................................
2-48
Gate array E05A02 in the printhead
drive circuit....................................................................
2-49
Printhead drive
circuit
.........................................................
2-50
Printhead software control
..................................................
2-51
A/D Converter Circuit...............................................................
2-52
Host Interface............................................................................
2-55
Ribbon Feed Mechanism............................................................
2-56
LQ-200/AP3000
2-i