AUTO ARC BENCHMARK User manual

June
1989
FORM:
121
989A
OWN
ERS
MANUAL
II
IT?
VTLiQFL_____
/ 1~J
I V..~ I
MILLER ELECTRIC
MFG.
CO.
718 S. BOUNDS
SI,
P.O.
Box
1079
APPLETON,
WI
54912
USA
ADDITIONAL
COPY
PRICE
$1.40
lMpOfl~TANT
_____________
Read
and
understand
the
entire
content3
of this
manual,
with
special
emphasis
on
the
safety
material
throughout
the
manual,
before
installing,
operating,
or
maintaining
this
equip
ment.
Thts
unit
and
these
instructions
are
for
use
only
by
persons
trained
and
experienced
in
the
safe
operation
of
welding
equipment.
Do
not
allow
un
trained
persons
to
install,
operate,
or
maintain
this
unit.
Contact
your
distributor
if
you
do
not
fully
understand
these instructions.
Effective
With
Serial No.
JJ368979
MODEL
BENCHMARKTM
BENCHMARKTM
Pro
MWG-160
Gun
NWSA CODE NO.
4579
PRINTED
IN
U.S.A.

- -~ -~
ONE
YEAR
LIMITED
WARRANTY
COVERAGE

Miller
Electric
Mfg.
Co.
warrants
to
the
buyer
who
purchases
this
Auto
Arc
Welder
(~Welder)
for
personal,
familyorhousehold
purposes
(Consumer)
thatthis Welderwill
be
free from
defects
in
material
andworkmanship
fora
period
of
one
year
from
the
date of
purchase.
This
warranty
covers
only
the
original purchaser
of
this
Welder.
Miller Electric
does
not
authorize
any
party,
including
its
authorized
distributors,
to offer
any
other
warranty
on
behalf
of
Miller
Electric.
Upon expiration
of the
warranty
period,
Miller
Electric
shall have
no
further
liabil
ity
related to
the
Welder,
excepton
warranty
claims
made
during
the
warranty period.
THIS
WARRANTY
IS OFFERED
IN
LIEU
OF
ANY OTHER
EXPRESS
WARRANTY;
AND,
EXCEPT
TO THE
EXTENT
PROHIBITED
BY
APPLICABLE
LAW,
THE
DURATION OF
ALL
IMPLIED
WARRANTIES,
INCLUDING
BUT
NOT
LIMITED
TO
THE
IMPLIED
WARRANTIES
OF MERCHAN
TABILITY AND FITNESS
FOR
A
PARTICULAR
PURPOSE,
IS
LIMITED TO THE DURATION OF
THIS WARRANTY.
Some
states
do
not
allow limitations
on
how
long
an
implied
warranty
lasts,
so
the
above limitation
may
not
apply
to
you.
This
warranty gives
you
specific
legal
rights,
and
you may
also
have other
rights
which
vary
from
state
to
state.
Except
as
specified
below,
Millers
warranty
does
not
apply
to
components having
normal
useful life
of less
than
one
(1)
year,
such
as
spot
welder
tips,
relay
and
contactor
points,
parts
that
come
in
contact
with the
welding
wire
including
nozzles
and
nozzle insulators where failure
does
not result from defect
in
workmanship
or
material.
Miller shall be
required
to
honorwarranty
claims
on
warranted
Equipment
in
the
event
of
failure
resulting
from
a
defect
within
the
following
periods
from
the date of
delivery
of
Equipment
to
the
original
user:
1.
Arc
welders,
power
sources,
and
components ...
1
year
2.
Original
main
power
rectifiers
3
years
(labor

1
year
only)
3.
All
welding
guns,
feeder/guns
and
torches
90
days
4.
Replacement
or
repair
parts,
exclusive
of
labor
60
days
WHAT IS
NOT COVERED

This
warranty
does
not
extend
to
any
Welder
subjected
to
misuse,
neglect,
accident,
or
in-
warranty
repair
by
anyone except
Miller
Electric.
Further,
this
warranty
only
extends
to those
purchasing
the Welder
for
per
sonal,
family
or
household
purposes.
Commercial
and
indus
trial
users
are
given
a
different
warranty.
REMEDY
FOR DEFECTIVE
WELDER

Upon receipt
of
any
defective
Welder,
Miller
Electric
will,
at
its
option,
repair
or
re
place
the
defective
Welder
at
its
expense,
refund
or
credit the
purchase
price
(less
reasonable
depreciation
based
on
actual
use),
or
reimburse the Consumer
for
the
cost
of
repair
or
re
placement
at
an
approved
Miller
Electric
warranty
station,
pro
vided that
the
purchaser
of that Welder
has
followed the
proce
dure
for
obtaining
warranty
performance
set forth below. The
Welder
so
repaired
or
used
as a
replacement
will be
shipped
to
the
purchaser
of
the
defective
Welder,
with
transportation
charges
prepaid
to
any
destination in
the continental United
States
(transportation
charges
on
shipments
to Alaska
or
Hawaii
will
be
paid
only
to
the
nearest
port
of
export).
THE
PURCHASERS REMEDIES
FOR
A
DEFECTIVE
WELDER,
TO
THE
EXTENT PERMITTED
BY
APPLICABLE
LAW,
ARE
LIMITED
TO
THE REMEDY PROVIDED BY THIS
WARRANTY:
AND,
TO THE
EXTENT ENFORCEABLE
UNDER
APPLICABLE
LAW,
MILLER
ELECTRIC SHALL
IN
NO
EVENT
BE LIABLE
FOR
CONSEQUENTIAL,
INCIDEN
TAL OR SPECIAL DAMAGES
ARISING
OUT
OF
THE
USE
OF,
OR INABILITY TO
USE,
THE
WELDER,
WHETHER
BASED
ON BREACH OF THIS
WARRANTY,
MILLER
ELECTRICS
NEGLIGENCE OR
OTHER
TORT,
OR
ON
ANY
THEORY
OF
STRICT LIABILITY.
Some
states
do
not
allow
the
exclusion
or
limitation of
conse
quential
or
incidental
damages,
so
the
above
limitations
may
not
apply
to
you.
PROCEDURE
FOR
OBTAINING WARRANTY
PERFORM
ANCE
As
soon
as
any
defect
in
a
Welder
becomes
known,
the
pur
chaser
of the
Welder
must,
within
thirty
(30)
days,
notify
an
approved
Warranty
Station
or
Miller
Electric
in
writing
of
the
defect.
The
purchaser
must
then,
within
the
one
year
warranty
period,
return
the
Welder
to
Miller
Electric
at
the
following
ad
dress:
Miller
Electric
Mfg.
Co.
1635 W.
Spencer
St.
P.O.
Box
1079
Appleton,
Wisconsin
54912
All
transportation
charges
to
Warranty
Station
or
Miller
Electric
must
be
prepaid.

ERRATA
SHEET
After
this manual
was
printed,
refinements
In
equipment
design
occurred.
This
sheet
lists
exceptions
to
data
appearing
later
in
this
manual.
IMPORTANT: This
model
comes
equipped
with
V-Grooved
drive rolls installed.
AMENDMENT TO
SECTION
3
SPECIFICATIONS
Amend
90
Ampere
Model
portion
of
Chart
3-2.
Duty
Cycle
90
Ampere
Models
0)
uJ
LI
10
16
20 2630 40 60
SOiO6OO1OO
X
DUTY
CYCLE
B.124
655-A
AMEN
DMENT
TO
SECTION
4INSTALLATION
Amend
step
10 of
Section
4-5.
INSTALL
AND
THREAD
THE
WIRE
10.
Route
the
welding
wire into the wire inlet
guide,
along
the drive roil
groove,
and into the
wire
outlet
guide
in
the
gun
cable.
AMENDMENT
TO
SECTION
7-
MAINTENANCE
&
TROUBLESHOOTING
Amend
Figure
7-1.
Wire
Drive
Assembly
And
Replacement
(see
Page
2
on
this
Errata
Sheet)
(For
70
Ampere
Models,
Effective With
Serial
No.
JK646341.
For
90
Ampere
Models,
Effective
With Serial
No.
JJ368979.)
Amend
Section
7-7.
REPLACING
THE WIRE
INLET
GUIDE
(Figure
7-1
on
this Errata
Sheet)
(For
70
Ampere Models,
Effective With
Serial
No.
JK646341.
For
90
Ampere
Models,
Effective
With
Serial
No.
JJ368979.)
160
126
100
76
60
375
0

Pressure
Pressure
Roll
Cover
Cotter
Pin
Drive
Roll
Setscrew
TC-121
488.A
FIgure
7-1.
WIre
Drive
Assembly
And
Replacement
a
WARNING:
HOT SURFACES
can cause severe
burns.

Allow
equipment
to
cool
before
cleaning.
1. Turn OFF
the welder.
2.
Open
the
left
side
access
door.
3.
Loosen the
drive
roll
pressure
adjustment
knob,
pivot
the
pressure
adjustment
arm
down~
away
from
the
cover.
Pivot
the
pressure
roll
assembly
up
until
it
is
in
the
open
position.
a
CAUTION:
LOOSE
WELDING WIRE
can cause
Injury.

Keep
firm
ho/don
wire
during
installation,
removal,
and
threading operations.
Spooled
wire has
a
tendency
to
unravel
rapidly
when
loosened from the
spool.
4.
Cut
the
welding
wire
at
the
point
where
it
enters
the
wire inlet
guide.
Pull
the
wire
out
through
the nozzle end
of
the
welding
gun.
5.
Remove
and
replace
the
inlet
guide.
IMPORTANT:
Wire
guides
should
be
installed
so
that
the
tip(s)
of
the
guide
is
as
close
to
the drive
roll
as
possible
without
touching.
6.
Thread
the
welding
wire
as
instructed
in
Section
4-5.
7.
Pivot
the
pressure
adjustment
arm
up
until ft
seats
on
top
of the
pressure
roll
assembly.
8.
Turn
the
pressure adjustment
knob
clockwise
until the drive
roll
assembly
is
secure.
Adjust
the
drive roll
pressure
just
enough
to
prevent
the
wire
from
slipping
on or
against
the
drive
roll
during operation.
9.
Close
and
secure
the
access
door.
AMENDMENT
TO
SECTION
8
ELECTRICAL
DIAGRAMS
Amend
Diagram
8.5.
Wiring
Diagram
For
90
Ampere
Models
(see
Page
3
on
this Errata
Sheet)
121
9B9APage2
Gun
Cable
Pressure Lever
Hinge
Pin
Pressure
Bearing
Screw
Pressure
Adjustment
~
Arm

Wire
inlet
Guide

Wiring
Diagram
No.
C-124
445-C
Diagram
8-5.
Wiring
Diagram
For
90
Ampere
Models

AMENDMENT
TO
SECTION
12
PARTS
LIST
Amend
Parts
List
as
follows:
Model
Quantity
Dia.
Part
Replaced
Benchmark
Mkgs.
No.
With
Description
Benchmark
Pro
41-2
010910 010910
WASHER,
flat-SAE
3/8
3
3
41-19
073
433
Deleted
Both
Models
(Eff w/JK664661)
41-20
010
678
Deleted
Both
Models
(Effw/JK664661)
41-21
GS1
003538
116996
VALVE,
ll5VAC2way
custom
port
1/8orf
(Etfw/JK664661)
1 1
41-22
010
296
Deleted
Both
Models
(Eff
w/JK664661)
41-29
121
088
126416
HANDLE,
molded
plastic
(Eff
w/JK71
6640)
1
1
41-
Added
126415
CLAMP,
saddle
(Eff
w/JK71
6640)
1 1
41-
Added
605
227
NUT,
nyl
hex
jam
.750
(Effw/JK664661)
1
1
42-54
119123
130900
BAFFLE,air(Effw/JK716640)
I
I
42-56
083
147
Deleted
BOTH
MODELS,
(Eff
w/JK71
66400)
45-5
Added
604
536
SCREW,
cap
stl
hexhd
.312-18
(Eff
w/JK646341)
1
45-6
Added
602
211
WASHER,
lock sfl
split
.312
(Etfw/JK646341)
1
45-7 Added
604 538
WASHER,
flat
st
SAE
.312
(Eff
w/JK646341)
2
45-8
118
871
129 893
INSULATOR,
housing-drive
(Effw/JK716640)
1 1
45-9
129
665
126838
DRIVE
ASSEMBLY,
wire
(Eff
w/JK646341)
1
45-11
118
928
124
817
HOUSING,
wire drive
(Eff
w/JK646341)
1
45- 604 534
Deleted
(Eff
wIJK646341)
45- 604
538
Deleted
(Eff w/JK646341)
45-
602
109
Deleted
(Effw/JK646341)
45-
120 678
058
549
GUIDE,
wire inlet
1/16
(Effw/JK646341)
1
45-
Added
604
537
NUT,
stl
hex full
fnsh
.312-18
(Eff
w/JK646341)
1
**First
digit
represents
page
no
-
digits
following
dash
represent
item
no.
BE
SURE
TO PROVIDE MODEL
AND
SERIAL
NUMBER
WHEN
ORDERING
REPLACEMENT PARTS.
121
989A
Paged

RECEIVING-HANDLING
Before
unpacking
equipment,
check
carton
for
any
dam-
Use the
following
spaces
to
record
the
Model
Designa
age
that
may
have
occurred
during
shipment.
File
any
tion and
Serial
or
Style
Number of
your
unit. The infor
claims for
loss
or
damage
with
the
delivering
carrier.
mation is located
on
the
data
card
or
the
nameplate.
Assistance
for
filing
or
settling
claims
may
be obtained
from the distributor and/or
the
equipment
manufactur-
Model
______________________________________
ers
Transportation
Department.
Serial
or
Style
No.
________________________
When
requesting
information
about this
equ!pment,
al
ways
provide
the Model
Description
and
Serial
or
Style
Date
of Purchase
____________________________
Number.
TABLE OF CONTENTS
Section
No.
Page
No.
SECTION 1

SAFETY
RULES
FOR OPERATION
OF ARC WELDING POWER
SOURCE
1-1.
Introduction
1
1-2.
General
Precautions
1
1-3.
Arc
Welding
3
1-4. Standards
Booklet
Index
5
SECTION
2-
SAFETY
PRECAUTIONS
AND
SIGNAL
WORDS
2-1
.
General Information
And
Safety
6
2-2.
Safety
Alert
Symbol
And
Signal
Words
6
SECTION
3
SPECIFICATIONS
3-1.
Volt-Ampere
Curves
8
3-2.
Duty
Cycle
8
3-3.
Description
9
3-4.
Supplied
Equipment
9
3-5. Personal
Safety
Equipment
9
3-6.
Optional
Equipment
9
3-7.
Consumable/Replacement
Parts
10
SECTION
4
-
INSTALLATION
4-1.
Locate
The
Welder
10
4-2.
Install The
Work
Clamp
10
4-3.
Set
The
Welding
Polarity
11
4-4.
Install
The
Welding
Gun
11
4-5.
Install
And
Thread
The
Wire
11
4-6.
Adjust
The
Hub
Tension
12
4-7.
Shielding
Gas
Installation
12
4-8.
Connect
To Power
13
4-9.
Feed
The Wire
14
SECTION
5

OPERATOR
CONTROLS
5-1.
Power
Switch
14
5-2.
ThicknessNolts
Switch
14
5-3.
Fine
Tuning/Wire
Speed
Control
15

Section
No.
Page
No.
SECTION
6
OPERATION
6-1.
Gas Metal
Arc
Welding
(GMAW)
15
6-2.
Flux
Cored
Arc
Welding
(FCAW)
18
6-3.
Shutting
Down
18
SECTION 7-
MAINTENANCE &
TROUBLESHOOTING
7-1.
Routine
Maintenance
18
7-2. Drive Roll
Cleaning
19
7-3. Cable
Inspection
19
7-4.
Welding
Gun
Inspection
And Maintenance
19
7-5.
Replacing
The
Drive
Roll
19
7-6.
Replacing
The
Pressure
Bearing
19
7-7.
Replacing
The Wire
Inlet
Guide
20
7-8.
Short
Circuit
Shutdown
(90
Ampere
Models
Only)
21
7-9.
Circuit
Board
Replacement
(90
Ampere
Models
Only)
21
7-10.
Replacing
The
Contact
Tube 22
7-11. Gun Wire And
Liner
Replacement
22
7-12.
Fuse
Fl
(70
Ampere
Models
Only)
22
7-13.
Thermal
Overload
Protection
23
7-14.
Troubleshooting
23
SECTION
8
ELECTRICAL DIAGRAMS
Diagram
8-1.
Circuit
Diagram
For
70
Ampere
Models
24
Diagram
8-2.
Circuit
Diagram
For 90
Ampere
Models
25
Diagram
8-3.
Circuit
Diagram
For 90
Ampere
Model
Short
Circuit
And
Burnback Control Board
PCi
25
Diagram
8-4.
Wiring
Diagram
For 70
Ampere
Models
26
Diagram
8-5.
Wiring
Diagram
For 90
Ampere
Models
27
SECTION
9
PROJECT INSTRUCTIONS
9-1.
Overview
28
9-2.
Dust
Pan
29
9-3.
Shop
Stool
30
9-4.
Adjustable
Support/Stand
31
9-5. Trailer
Dolly
32
SECTION
10 WELDING
TECHNIQUES
&
TROUBLESHOOTING
10-1.
Gas
Metal
Arc
Welding
(GMAW)

Continuous
Seam
33
10-2.
Troubleshooting
The Gas Metal
Arc
Welding (GMAW)
Process
....
34.
SECTION 11

AUTO
BODY REPAIR
APPLICATION
11-1.
Pointers
For
Welding
Auto
Body
Sheet
Metal
38
11-2.
-Procedure For
Welding
Mild
Steels
38
11-3.
Procedures
For
Welding
Door
Panels
38
11-4.
How To Prevent
Glass
Breakage
And
Spatter
On
Windows
39
11-5.
Procedures
For
Welding
Fenders
And
Quarter
Panels
39
11-6.
Welding
Frames
And
High
Strength
(HSS)
Steels
39

Section
No.
Page
No.
SECTION
12
PARTS LIST
Figure
12-1.
Main
Assembly
40
Figure
12-2.
Circuit
Card,
Shutdown/Burnback
PCi
43
Figure
12-3.
Drive
Assembly,
Wire
(Benchmark
Pro
Illustrated)
44
Figure
12-4~
Exploded
View
Of
MWG-160B
Gun
46
LIST
OF
CHARTS
AND
TABLES
Table
3-i.
Specifications
7
Chart
3-1.
Volt-Ampere
Curves
8
Chart
3-2.
Duty
Cycle
8
Table
4-1.
Maximum Allowable Extension Cord
Lengths
14
Table
6-1.
Suggested
Welding
Settings
16
Table
7-1.
Maintenance Schedule
18
Table
7-2.
Troubleshooting
23
Table
9-i.
Dust Pan
Material
List
29
Table
9-2.
Shop
Stool
Material List
30
Table
9-3.
Adjustable
Support/Stand
Material
List
31
Table
9-4.
Trailer
Dolly
Material List
32