Digital Equipment LA30 N Service Manual Download

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4.10

Diagnostics .............................................................................................................................................. 4-48

4.10.1

Self-test printing ................................................................................................................................ 4-48

(1)

Starting self-test printing ............................................................................................................ 4-48

(2)

Checking printer performance ................................................................................................... 4-49

(3)

Stopping self-test printing .......................................................................................................... 4-49

4.10.2

Hex dump .......................................................................................................................................... 4-50

(1)

Starting hex dump printing ........................................................................................................ 4-50

(2)

Stopping hex dump printing ....................................................................................................... 4-50

4.10.3

Control panel maintenance functions initiated when power goes on ................................................ 4-51

CHAPTER 5

PRINCIPLES OF OPERATION .......................................................................................... 5-1

5.1

Overview ................................................................................................................................................... 5-1

5.2

Mechanical Operation ............................................................................................................................... 5-2

5.2.1

Print head drive ................................................................................................................................... 5-2

5.2.2

Carriage drive ...................................................................................................................................... 5-3

5.2.3

Ribbon feed ......................................................................................................................................... 5-4

5.2.4

Paper feed ............................................................................................................................................ 5-5

(1)

Continuous forms feeding .......................................................................................................... 5-6

(2)

Cut-sheet feeding ....................................................................................................................... 5-8

(3)

Paper selection ........................................................................................................................... 5-9

(4)

Autoloading ................................................................................................................................ 5-10

(5)

Paper end detection .................................................................................................................... 5-11

5.2.5

Print head gap control (paper thickness adjustment) .......................................................................... 5-14

5.2.6

Color ribbon shift motor (option) ........................................................................................................ 5-15

5.2.7

Option detection mechanism ............................................................................................................... 5-16

5.3

Electrical Operation ................................................................................................................................... 5-17

5.3.1

System configuration .......................................................................................................................... 5-17

(1)

Printer control board (ROM board) ............................................................................................ 5-19

(2)

Power supply unit ...................................................................................................................... 5-19

(3)

Sensors ....................................................................................................................................... 5-19

(4)

Control panel .............................................................................................................................. 5-19

5.3.2

Main controller .................................................................................................................................... 5-23

5.3.3

Interface control .................................................................................................................................. 5-25

(1)

Centronics parallel interface ...................................................................................................... 5-25

(2)

RS-423 serial interface ............................................................................................................... 5-26

5.3.4

Carriage motor control ........................................................................................................................ 5-27

5.3.5

Print head control ................................................................................................................................ 5-31

5.3.6

Paper feed control ............................................................................................................................... 5-33