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G-4
ELECTRICAL DIAGRAMS
LN-8
OPERATING SCHEMATIC
5
4
2
3
6
1
32A
531
4
504
502
2
2
4
1CR
504
N.A.
32
32A
5 AMP CIRCUIT
BREAKER
TP201
C204
77
76
75
R20
T1
526
525A
C205
525
R205
523
524
S1
R204
S2
536
R202
D205
529
2CR
528
D204
1CR
C201
R206
SCR
531
C202
R203
C203
(R)
(W)
627
S3
683
682
1CR
D201
D202
C206
R201
626
F201
531
1CR
32A
7
32A
D103
D104
C107
PT101
C109
7
TP101
SCR101
SCR102
C108
PT101
D107
D105
D106
539
R123
541
(B)
(U)
R118
DZ101
R105
R127
R111
R109
R113
C105
C106
PT101
R106
C112
QU101
R107
R129
D113
C103
D102
R108
R112
C111
D101
D114
D108
539
R125
R124
R126
R128
R119
R120
D111
Q103
D110
S
F
Q101
R114
D109
R116
R117
C113
635
R115
C104
R102 R121
Q102
R122
D112
L101
R103
R110 R9
632
631
C110
634
R101
C102
A
B
CV
VV
S304
R309
C306
Q302
C305
C303
DZ302
R310
C304
PT301
C302
R306
R302
QU301
R308 R305
R303
R304
Q301
C307
R301
DZ301
C301
D301
D302
D303
D304
TP301
R311
CONTROL CIRCUIT (BOARD #1)
C101
C102
C103
C104
C105
1MFD
2MFD
39MFD ~10%
4.7MFD
.10MFD
C106, C110,C111
C112, C113
.02 MFD
C107, C108
.047MFD
C109 .005MFD
D101
D102
D103
D104
D105
D106
D107
D108
D109
D110
D111
D112
D113
D114
1A.
1A.
1A.
1A.
16A.
1A.
1A.
1A.
1A.
1A.
1A.
1A.
20V.
16A.
16A.
DZ101
R101
R102
R103
R105
R106
R107
R108
R109
R110
R111
R112
R113
R114
R115
6.8K
10K
4.7K
4.7K
33K
33K
750
27K
39K
10K
68K
2K TRIMMER
15
50K TRIMMER
R116
R117
R118
R119
R120
R121
R122
R123
R124
R125
R126
R127
R128
R129
10K
22K
27K
15K
1.5K
10K
150
15K
4.7K 4W
.25 7W
1K TRIMMER
1K TRIMMER
1K
4.7K 4W
L101
Q101
Q102
Q103
QU101
TP101
SCR101
SCR102
PT101
5.6MH
2N4125
2N4123
2N5815
2N6027
TRANSIENT PROTECTION
12A 400V
12A 400V
1:1:1 PULSE TRANSFORMER
RELAY CIRCUIT (BOARD #2)
C201
C202
C203
C204
1CR
D201
50MFD
.02MFD
50MFD
.005MFD
C205
C206 .005MFD
50MFD
3PDT 24V.D.C.
1A.
D202
D203
D204
D205
1A.
1A.
1A.
1A.
R201 40 12W
R202
R203
R204
R205
R206
100
100K
27
4.7K
1K
F201 1/2A 125V CR 250V
SLOW BLOW FUSE
SCR201 4A 400V
TP201 TRANSIENT PROTECTION
VARIABLE VOLTAGE CIRCUIT (BOARD #3)
C301
C302
C303
C304
C305
C306, C307
2MFD
.10MFD
.01MFD
.047MFD
.01MFD
.02MFD
D301
D302
D303
D304
1A.
2A.
3A.
4A.
DZ301 62V
DZ302 10V
Q301
Q302
2N3393
2N4125
PT301 1:1:1 PULSE TRANSFORMER
TP301 TRANSIENT PROTECTION
R301
R302
R303
R304
R305
R306
R307
R308
R309
R310
R311
6.8K
3.3K
100
5.6K (2%)
1K (2%)
3.9K (2%)
4.7K 2W
5K TRIMMER
15
47
68
S304 POWER SOURCE
SELECTOR SWITCH
QU301 UJT
COMPONENTS NOT ON P.C. BOARD
R4
R9
T1
S1
S2
S3
R20
2CR
4CR
2 50W
5K 2W POT.
10K 2W POT.
110-24V TRANSFORMER
REED SWITCH (ACTUATED BY WELDING CURRENT)
GROUNDING LEAD PROTECTOR
SPST GUN SWITCH
SPDT INTERLOCK SWITCH
SPDT DIRECTION SWITCH
LEAD COLOR CODING
B - BLACK
W - WHITE
R - RED
U - BLUE
SINCE COMPONENTS OR CIRCUITRY ON A PRINTED CIRCUIT
BOARD MAY CHANGE WITHOUT AFFECTING THE INTER-
CHANGEABILITY OF A COMPLETE BOARD, THIS DIAGRAM
MAY NOT SHOW THE EXACT COMPONENTS OR CIRCUITRY
OF CONTROLS HAVING A COMMON CODE NUMBER.
GND LEAD
PROTECTOR
COIL
.1
R4
31
GND
N.B.
CASE GROUNDING
SCREW
FOR VARIABLE VOLTAGE P.C. BOARD L5039-1 OR HIGHER,
USE M16441 SCHEMATIC FOR COMPONENT VALUES AND
CIRCUIT CONNECTIONS
WIRE
FEED
MOTOR
FIELD
TO POWER
SOURCE TO
OPERATE
CONTACTOR
GND LEAD
PROTECTOR
SWITCH
THERMAL
CIRCUIT
BREAKERS
TH1
M16802 SCHEMATIC FOR COMPONENT VALUES AND
CIRCUIT CONNECTIONS
GND
541
543
567
568
21
CASE
GROUNDING
SCREW
N.A. JUMPER PLUG IS REMOVED AND CONNECTOR "B" IS PLUGGED INTO
OPTIONAL BURNBACK P.C. BOARD. SEE S15123 FOR OPERATING
SCHEMATIC.
N.B. RESISTOR USED ON CODES 9090 AND BELOW ONLY. FOR CODES
ABOVE 9090 THE GROUNDING LEAD PROTECTOR CONNECTS
DIRECTLY TO THE CASE GROUNDING SCREW.
VARIABLE VOLTAGE CONTROL CIRCUIT TO RIGHT OF THIS LINE. TO
OPERATE LN-8 WHEN THIS CIRCUIT IS NOT INSTALLED IN UNIT,
POINT "A" TO "B" IS JUMPERED.
PER E1537
ELECTRICAL SYMBOLS
METER KIT RECEPTACLE
PT301
21
POWER
SOURCE
TO
ARC
VOLTAGE
568
567
TO
GUN
CABLE
LN-8
SHUNT
D203
522
201
C101
R307
FOR CONTROL P.C. BOARDS L5767-1 AND HIGHER, USE
637
12-3-92E
M14680
G-4
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NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided
for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the machine.