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Lexmark 4227 Service Manual - Page 35

Service checks, Auto Gap service check, Theory of operation

UPC - 734646117104

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4227-300 Service checks Auto Gap service check Theory of operation The Auto Gap motor and Gap Home sensor automatically set the printhead gap for the thickness of paper being used by rotating the eccentric carrier shaft. The printer detects maximum gap with the Gap Home sensor, and minimum gap by driving the printhead against the platen. In addition to compensating for the thickness of the paper itself, the printer must increase the air gap for thicker papers. With Auto Gap On, the following occurs: • POST • Auto Gap resets. • The printer unloads paper, if it is loaded, to prepare to measure the travel span. • The Auto Gap motor drives the printhead against the platen to measure the total travel span. • Auto Gap resets again, to make room for paper to be loaded. • The paper feeds to the print line. • The Auto Gap motor drives the printhead against the paper to measure the total travel span minus the paper thickness. • Auto Gap resets again. • The printhead moves to the appropriate gap position for the installed paper. • The Ready LED comes on, the carrier centers, and the paper moves to the tearoff position. Diagnostic information 2-11

Section	Page
Table of contents	3
Safety information	7
Preface	12
1. General information	13
Description	13
Voltage, ground, and continuity readings	14
Voltage readings	14
Ground checks	14
Continuity readings	14
Maintenance approach	15
Options	15
Tools	15
Abbreviations	16
Using the operator panel	17
Using the function menus	18
Setting printer functions	19
Overview of function menus	20
Buttons	22
Lights	23
2. Diagnostic information	25
Start	25
Error indication table	25
Symptom tables	27
Abnormal Indications	28
Abnormal print operation problems	28
Auto Sheet Feeder problems	29
6XX Error indications	29
Paper feed problems	30
Operator panel problems	32
Power Problems	32
Print quality problems	33
Ribbon feed problems	34
Service checks	35
Auto Gap service check	35
Theory of operation	35
Auto Sheet Feeder (ASF) service check	37
Auto Sheet Feeder principles of operation	37
Carrier drive service check	39
Intermittent problem service check	40
No print or abnormal print service check	43
Operator panel service check	44
Paper feed service check	45
POST service check	48
Power failure service check	49
Print quality service check	51
Print wire drive failure service check	52
Ribbon drive service check	54
Tractor 2 service check	55
63D Tractor 2 HP error	55
Tractor 2 installed, but not shown in User Menu	57
Paper feed problems	58
3. Diagnostic aids	59
Power-On Self Test (POST)	59
Hex trace mode	60
Hex trace mode sample	60
Interface selection	61
Operation with the top cover removed	61
Service Menu	61
Button Test	62
Factory Setting	62
Printhead Bank	62
Jam/PSet Sensor Test	62
Impact force	62
Log clear	62
Print Test	63
Other print tests	63
Error log	63
4. Repair information	65
Handling ESD-sensitive parts	65
Adjustments	66
Printhead installation adjustment	66
Printhead-to-platen gap adjustment	66
Printhead-to-platen gap left and right	66
Printhead-to-platen gap electronic setting	67
Bidirectional print adjustment	67
Removals	69
Top cover removal	69
To Reinstall:	71
Auto Gap motor removal	72
Auto Sheet Feeder gears removal	73
Auto Sheet Feeder pick-up roller removal	74
Belt tension pulley plate assembly removal	75
Base assembly removal	75
Carrier removal	76
To reinstall:	78
Carrier motor assembly removal	79
To reinstall:	79
Carrier plate removal	80
Label jam removal	80
Lower feed roller removal	81
To reassemble:	84
Lower pinch roller removal	85
Main logic board removal	85
To reinstall:	85
Memory Module removal	86
Operator panel assembly removal	86
Paper Empty sensor/TOF sensor removal	86
To replace the TOF Sensor Flag:	88
Paper feed motor removal	89
To reinstall	89
Paper guide removal	89
Paper guide/platen assembly removal	89
Paper Select lever removal	89
Paper Select sensor removal	90
Paper separator removal	91
Power supply removal	93
Power supply fan removal	93
Print unit removal	93
To Reinstall	95
Printhead removal	96
To reinstall	96
Printhead cables removal	97
To reinstall	97
Ribbon drive motor assembly removal	98
Right side frame removal	99
To reassemble	101
Sub logic board removal	101
To reinstall	101
Upper feed roller removal	102
5. Preventive maintenance	103
Lubrication	103
Specified lubricants	103
Lubrication points	104
Oil	104
Grease	104
6. Locations and connectors	105
4227-300	105
Main Logic Board Connectors	106
Operator panel connectors	107
Component locations	108
Component location illustrations	109
Component location illustrations (Continued)	110
Signal connections	111
Main Logic Board<-->Paper Empty & TOF Sensors	113
Main Logic Board<-->Carrier Motor Cable #1	113
Main Logic Board<-->Paper Feed Motor	113
Main Logic Board<-->Tractor 2 DIN	114
Main Logic Board<-->Carrier Motor Cooling Fan	114
Main Logic Board<-->5 V dc Power	114
Main Logic Board<-->Operator Panel	115
Main Logic Board<-->Tractor PSet & Jam Sensors	115
Main Logic Board<-->Ribbon Motor	116
Main Logic Board<-->Auto Gap Motor	116
Main Logic Board<-->Serial Board	116
Serial Board<-->Serial Cable	117
Sub Logic Board<-->Printhead	118
Operator Panel Board<-->Ribbon Cover Sensor	118
Tractor 2 cable connectors	119
Connector block diagram	120
7. Parts catalog	123
How to use this parts catalog	123
Assembly 1: Covers and operator panel	124
Assembly 2: Paper feed	126
Assembly 3: Carrier	128
Assembly 4: Base and electronics	130
Assembly 5: ASF side frame/covers	132
Assembly 6: ASF roller/support	134
Assembly 7: Tractor 2 option	136
Index	139
A	139
B	139
C	139
D	139
E	139
F	139
H	139
L	139
M	139
O	139
P	139
R	139
S	140
T	141
U	141