Craden Peripherals DP8 technical manual Theory of Operation, Maintenance

3.13.7	Erratic Document Feed, Mispositioning or Overprinting	20
3.13.8	Rollers Run at Power-Up or After Document Ejected	20
3.13.9	Erratic Character Spacing or Carriage Hitting End Stops	20
3.13.10	Interface Inoperative	20

4.0THEORY OF OPERATION

4.1	OVERVIEW		21
	4.1.1	Carriage Drive Assembly	21
	4.1.2	Document Drive Assembly	21
	4.1.3	Switching Power Supply	21
	4.1.4	Main Printed Circuit Board	22
	4.1.5	Keypad/Display Assembly	22

4.2ELECTRONICS IN DETAIL

4.2.1	Low Voltage Supplies	22
4.2.2	Microprocessor System	22
4.2.3	Stepper Motor Drivers	22
4.2.4	Printhead Drivers	25
4.2.5	Keypad and Display	25
4.2.6	Sensors	25
4.2.7	Character Printing	25

5.0MAINTENANCE

5.1 LUBRICATION AND CLEANING

	5.1.1	Lubrication	27
	5.1.2 Document Feed Roller Cleaning		27
	5.1.3	Sensor Cleaning	27
	5.1.4	Printhead Cleaning	28
	5.1.5 Document Print Area Cleaning		28
	5.1.6	Cabinet Exterior Cleaning	28
5.2	SERVICE PARAMETER SET-UP PROCEDURE		29
5.3	ELECTRICAL ADJUSTMENTS		29

5.4MECHANICAL ADJUSTMENTS

5.4.1	Printhead Gap	30
5.4.1.1	Ribbon Shield Removal/Replacement	31
5.4.1.1.1 Ribbon Shield Face Inspection		32
5.4.2	Carriage Drive Belt Tension	33
5.4.3	Document Drive Belt Tension	33
5.4.4	Carriage Shaft Cam and Shaft Rack	33
5.4.5	Rear Document Roller Spring Force	33
5.4.6	Auto Alignment Gate Ramp	34
5.4.7	Auto Alignment Gate Height	34
5.4.8	Front Document Roller Spring Force	35
5.4.9	Auto Alignment Skew Sensor Calibration	35

5.5REPLACEMENT PROCEDURES

5.5.1	Cabinet	35
5.5.2	Main PCB	35
5.5.3	Sensor PCB	36
5.5.4	Keypad	36
5.5.5	Display	36
5.5.6	Power Supply PCB	36
5.5.7	Carriage Motor	36
5.5.8	Document Motor	37
5.5.9	Printhead	37
5.5.10	Carriage Drive Belt	37
5.5.11	Document Drive Belt	37