OKIDATA Pacemark 3410 Service Handbook page 8

SECTION TWO: PRINCIPLES OF OPERATION
2.1 ELECTRICAL OPERATION.......................................................................................... 2-1
2.1.01 General Information.......................................................................................... 2-1
2.1.02 Microprocessor (MPU) and Peripheral Circuits ............................................... 2-2
Microprocessor .......................................................................................................... 2-2
Program ROM for the MPU ...................................................................................... 2-2
DRAM........................................................................................................................ 2-2
EEPROM ................................................................................................................... 2-2
Interface/Motor Control LSI ...................................................................................... 2-3
Space Motor Enable / Speed Control................................................................... 2-3
Line Feed Motor Phasing Control........................................................................ 2-3
Bail Motor Phasing Control ................................................................................. 2-3
Dot ON Timing signal generation........................................................................ 2-3
Printhead / Bottom Tractor Feed Control LSI ........................................................... 2-3
Printhead Drive Control ....................................................................................... 2-3
2.1.03 Initialization ..................................................................................................... 2-4
Block Diagram ........................................................................................................... 2-5
2.1.04 Interface Control ............................................................................................... 2-6
Parallel Interface ........................................................................................................ 2-6
RS232-C Serial Interface ........................................................................................... 2-7
2.1.05 Printhead Drive Circuit ..................................................................................... 2-8
2.1.06 Spacing Drive Circuit ....................................................................................... 2-8
2.1.07 Line Feed Circuit .............................................................................................. 2-9
2.1.08 Alarm Circuits................................................................................................. 2-10
Fault Alarm Circuit (in Power Supply Unit)............................................................ 2-10
Printhead Overheat Alarm Circuit ........................................................................... 2-10
Cover Open Alarm Circuit....................................................................................... 2-10
2.1.09 Paper End Detection Circuit ........................................................................... 2-10
2.1.10 Power Supply .................................................................................................. 2-11
Voltage / Signal Table ............................................................................................. 2-11
2.2 MECHANICAL OPERATION ..................................................................................... 2-12
2.2.01 Printhead Mechanism...................................................................................... 2-12
Head Gap Adjusting................................................................................................. 2-12
2.2.02 Spacing Mechanism ........................................................................................ 2-14
Spacing Operation.................................................................................................... 2-14
2.2.03 Ribbon Drive Mechanism ............................................................................... 2-15
Ribbon Cartridge...................................................................................................... 2-15
Ribbon Feed Operation ............................................................................................ 2-15
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