G-11
ELECTRICAL DIAGRAMS
SQUARE WAVE TIG 255
CONTROL BOARD SCHEMATIC — SQUARE WAVE TIG 255
(G2150)
D 4 6
1 0 0
R14
1.00K
R113
+ 1 5 V
I O G N D
J 5
1
S C R G A T E
1 0 0 V
1A
Q 6
J 5
3
J 8
11
16VAC
A U X S C R 3
A U X S C R 3
windings )
( 1 o f 5 X F M R
s e c o n d a r y
J 8
5
S C R C A T H O D E
1.00K
R118
3
3
475K
R116
C N Y 1 7 - 3
O C I 6
4
2
1
6
5
267
R64
+ 1 5 V
S C R G A T E
1 W
1 8 V
D Z 5
1 W
3 0 V
D Z 6
1.00K
R112
475K
R16
J 5
8
D 4 3
267
R181
1.00K
R20
D 4 4
D 4 5
D 4 8
D 5 0
1 W
1 8 V
D Z 4
D 5 2
1.00K
R25
J 5
6
C N Y 1 7 - 3
O C I 3
4
2
1
6
5
4 0 V
6 0 0 m A
Q 5
1 0 0
R168
1 0 0
R182
D 4 7
2 7
3 5 V
C 2 7
1.00K
R115
1.0
3 5 V
C 4 7
1.0
3 5 V
C 4 8
1 0 0 0
3 5 V
C 4 2
D 9 9
2 0
5 0 V
C 4 3
D 7 3
D 7 1
D 9 2
D 1 0 0
D 2 3
1 W
1 2 V
D Z 1 7
D 7 2
4.7
3 5 V
C 6 6
4 . 7 5 K
R42
7 4 H C 5 7 3
X 2 0
2 0
10
D 4
X 1 0
11
10
5 0 V
0.1
C 3
S 1 8 6 4 7 - 2
1 0 K
R223
1 0 K
R211
X 1 0
13
12
X 1 0
5
6
D 2 4
D 2
1 0 K
R224
+ 1 5 V
N G N D
-15V
N G N D
L C D G N D
N G N D
I O + 5 V
N + 5 V
I O G N D
L G N D
N G N D
I O G N D
7 8 1 5
7 8 0 5
7 9 1 5
V s s
V d d
M C 6 8 H C 1 1
X 3
1
2 6
G N D
IN
O U T
X 1 2
D101
4 7 5 K
R200
4 0 V
6 0 0 m A
Q1
4.7
3 5 V
C 6 5
C 4 1
1 W
1 2 V
D Z 1 5
1 0 0 K
R 1 9 9
O U T
IN
G N D
X 1 6
G N D
IN
O U T
X 1 5
D 2 5
C A P A C I T O R S =
U N L E S S O T H E R W I S E S P E C I F I E D )
. 0 2 2 / 5 0 V
D I O D E S =
1A, 400V
0 1 / 0 3 / 9 4
( U N L E S S O T H E R W I S E S P E C I F I E D )
S Q U A R E W A V E T I G 2 5 5 C O N T R O L B O A R D
1 / 4 W
(
M F D
G E N E R A L I N F O R M A T I O N
U N L E S S O T H E R W I S E S P E C I F I E D )
R E S I S T O R S = O h m s (
3 3 0 7 4 A
X 1 4
4
11
X 3 2 _ + 5 V
X 3 1 _ + 5 V
I O G N D
+ 1 5 V
5 0 V
0.1
C 1 4
T C F 6 0 0 0
X 3 2
8
1
5 0 V
0.1
C 1 5
X 3 2 G N D
X 3 1 G N D
I O G N D
I O G N D
-15V
T C F 6 0 0 0
X 3 1
8
1
5 0 V
0.1
C 1 2
5 0 V
0.1
C11
3 3 0 7 4 A
X11
4
11
5 0 V
0.1
C 7 0
N G N D
2 2 1 K
R 2 7
1 0 0 K
R 3 9
4 7 . 5 K
R 4 0
47.5K
R30
5 0 V
0.1
C 8 1
4 7 . 5 K
R32
J 6
12
X11
14
12
13
1 0 0 0 V
7 5 0 p
C 7 9
1 W
1 2 V
D Z 1 6
1 W
1 2 V
D Z 1 4
3 0 0 0 V
. 0 0 4 7
C 4 9
47.5K
R29
1N4007
D11
47.5K
R31
1N4007
D 2 2
47.5K
R28
1N4007
D 2 1
1N4007
D 1 0
D 3 0
1.00K
R 6 9
100K
R44
1.00M
R 5 5
J 6
5
1.00M
R 3 8
1 0 0 0 V
7 5 0 p
C 8 0
D 5
J 8
1
J 8
2
3 0 0 0 V
. 0 0 4 7
C 6 7
X 3 2
7
X 3 1
7
X 3 1
6
V B
N G N D
V o l t a g e F B
E L E C T R O D E
W O R K
36VAC CT
1 6 V A C
1 6 V A C
1 6 V A C
3 6 V A C C . T .
2 4 V A C
1 2 0 V A C
C O N T R O L T R A N S F O R M E R
D 5 3
1 0 0
R24
D 4 9
1.00K
R226
4 0 V
6 0 0 m A
Q 3
X 1 0
1
2
1.00K
R225
4 7 5 K
R 1 3 6
1 0 0
R169
J 8
6
D 7 7
J 8
12
4 0 V
6 0 0 m A
Q 1 6
C N Y 1 7 - 3
O C I 4
4
2
1
6
5
1 0 0
R21
15.0K
R 1 3 7
X 1 0
3
4
2 6 7
R 1 8 4
267
R23
2 6 7
R 1 8 5
4 0 V
6 0 0 m A
Q 1 7
D I S P L A Y C O M M O N
L G N D
X 3 1 G N D
N O I S Y C O M M O N
N G N D
I O G N D
X 3 1 C O M M O N
P R O C E S S O R I O C O M M O N
X 3 2 C O M M O N
L E G E N D
( G R O U N D A N D + 5 V N E T S )
L C D G N D
L O G I C C O M M O N
X 3 2 G N D
P R O C E S S O R I O + 5 V S U P P L Y
X 3 1 + 5 V S U P P L Y
N O I S Y + 5 V S U P P L Y
L + 5 V
X 3 2 _ + 5 V
N + 5 V
L C D + 5 V
X 3 2 + 5 V S U P P L Y
D I S P L A Y + 5 V S U P P L Y
L O G I C + 5 V S U P P L Y
I O + 5 V
X 3 1 _ + 5 V
D 5 1
475K
R19
2.21K
R134
D 5 4
I O G N D
I O + 5 V
L C D + 5 V
X 3 1 G N D
I O + 5 V
I O + 5 V
I O G N D
I O G N D
X 3 1 _ + 5 V
I O G N D
L + 5 V
1 0 K
R 2 2
1 0 0 V
1A
Q 4
1 W
3 0 V
D Z 7
2 7
3 5 V
C 2 9
+ 1 5 V
2 7
3 5 V
C 2 8
S C R C A T H O D E
1
1
windings )
( 1 o f 5 X F M R
s e c o n d a r y
A U X S C R 1 , 2
+ 1 5 V
1 0 0 V
1A
Q 2
A U X S C R 1 , 2
475K
R65
16VAC
1 W
1 8 V
D Z 8
267
R12
1 0 0
R26
C N Y 1 7 - 3
O C I 5
4
2
1
6
5
D 7 6
1 0 0
R170
1.00K
R114
J 5
7
J 5
2
1 0 0
R183
D 5 8
1 W
3 0 V
D Z 1 0
D 5 9
1 0 0 K
R 6 7
16VAC
D1
D 6
D 7
J 8
10
J 5
4
D 5 5
J 8
4
1.00K
R120
D 5 6
D 5 7
1 0 0
R171
1 W
3 0 V
D Z 1
1 W
1 8 V
D Z 9
1 0 0
R18
1 0 0 V
1A
Q 1 2
J 5
9
1 0 0
R17
A U X S C R 4
S C R C A T H O D E
windings )
( 1 o f 5 X F M R
s e c o n d a r y
A U X S C R 4
S C R C A T H O D E
4
4
S C R G A T E
2
2
S C R G A T E
2 7
3 5 V
C 3 0
V O L T _ F B
C T
.1
5 0 V
C 3 8
2.21K
R212
windings )
( 1 o f 5 X F M R
s e c o n d a r y
5 0 V
0.1
C 6 9
X 3 1
5
X11
1
3
2
-15V
N G N D
7 4 H C 5 7 3
X 2 2
2 0
10
2 2 1 K
R 6 3
.1
5 0 V
C 4 5
1 0 K
R 9
N G N D
X 3 2 G N D
X 3 2 _ + 5 V
L G N D
L G N D L G N D
L G N D
5 0 V
0.1
C 1 0
7 4 H C 5 7 3
X 2 1
2 0
10
5 0 V
0.1
C 7
1.0
3 5 V
C 4 4
X 1 0
9
8
1.00K
R 2 1 4
I O G N D
L + 5 V
X 1 0
7 4 H C 1 4
7
14
Z E R O C R O S S
J 8
7
3 0 0 0 V
. 0 0 4 7
C 6 8
D 3
A
VOLTAGE FEEDBACK
ZERO CROSS
SCR 2,4
SCR 1,3
A 4 8 2 . 1
T O A 4 8 2 . 2
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n to Section TOC
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n to Section TOC
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n to Section TOC
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n to Section TOC
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n to Master TOC
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n to Master TOC
NOTE: Lincoln Electric assumes no responsibility for liabilities resulting from board level troubleshooting. PC Board
repairs will invalidate your factory warranty. This Printed Circuit Board schematic is provided for reference only. It may not
be totally applicable to your machine's specific PC board version. This diagram is intended to provide general information
regarding PC board function. 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.
