Chicago Electric 66042 Installation manual

DC INVERTER
ARC WELDING MACHINE
Model 66042
SET UP AND OPERATING INSTRUCTIONS
Diagrams within this manual may not be drawn proportionally.
Due to continuing improvements, actual product may differ slightly from the product described herein.
Distributed exclusively by Harbor Freight Tools®.
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our website at: http://www.harborfreight.com
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Copyright©2008 by Harbor Freight Tools®. All rights reserved. No portion of this
manual or any artwork contained herein may be reproduced in any shape or form
without the express written consent of Harbor Freight Tools.
For technical questions or replacement parts, please call 1-800-444-3353.

Page 2SKU 66042 For technical questions, please call 1-800-444-3353.
TABLE OF CONTENTS
IMPORTANT SAFETY INFORMATION............................................................................3
GENERAL SAFETY RULES............................................................................................3
SPECIFIC SAFETY RULES.............................................................................................5
SPECIFICATIONS............................................................................................................8
UNPACKING....................................................................................................................8
PRODUCT FEATURES....................................................................................................8
ASSEMBLY INSTRUCTIONS..........................................................................................9
WORKPIECE & WORK AREA SET UP.........................................................................10
GENERAL OPERATING INSTRUCTIONS....................................................................10
MAINTENANCE & SERVICING.....................................................................................12
TROUBLESHOOTING...................................................................................................13
PLEASE READ THE FOLLOWING...............................................................................13
PARTS LIST & ASSEMBLY DIAGRAM.........................................................................14
ELECTRICAL SCHEMATIC...........................................................................................15
WARRANTY INFORMATION.........................................................................................16

Page 3SKU 66042 For technical questions, please call 1-800-444-3353.
SAVE THIS MANUAL
Keep this manual for the safety warn-
ings and precautions, assembly, operating,
inspection, maintenance and cleaning pro-
cedures. Write the product’s serial number
in the back of the manual (or month and
year of purchase if product has no num-
ber). Keep this manual and the receipt in
a safe and dry place for future reference.
IMPORTANT SAFETY
INFORMATION
In this manual, on the labeling,
and all other information
provided with this product:
This is the safety alert
symbol. It is used to alert
you to potential personal
injury hazards. Obey all
safety messages that
follow this symbol to avoid
possible injury or death.
DANGER indicates
a hazardous
situation which, if not
avoided, will result in death or
serious injury.
WARNING
indicates a
hazardous situation which, if
not avoided, could result in
death or serious injury.
CAUTION, used
with the safety
alert symbol, indicates a
hazardous situation which, if
not avoided, could result in
minor or moderate injury.
NOTICE is used to
address practices
not related to
personal injury.
CAUTION, without
the safety alert
symbol, is used to address
practices not related to
personal injury.
General Safety Rules
WARNING! Read all
instructions.
Failure to follow all instructions
listed below may result in
electric shock, re, and/or
serious injury.
SAVE THESE INSTRUCTIONS
Work area safety1.
Keep work area clean and well lit.a.
Cluttered or dark areas invite acci-
dents.
Do not operate the Welder in ex-b.
plosive atmospheres, such as in
the presence of ammable liquids,
gases or dust. Power tools create
sparks which may ignite the dust or
fumes.
Keep children and bystanders awayc.
while operating the Welder. Distrac-
tions can cause you to lose control.
Electrical safety2.
Avoid body contact with groundeda.
surfaces such as pipes, radiators,
ranges and refrigerators. There is
an increased risk of electric shock if
your body is grounded.
Do not touch exposed electricalb.
parts.
DANGER
WARNING
CAUTION
NOTICE
CAUTION

Page 4SKU 66042 For technical questions, please call 1-800-444-3353.
Do not expose the Welder to rainc.
or wet conditions. Water entering a
power tool will increase the risk of
electric shock.
Do not abuse the Power Cord (21).d.
Never use the Cord for pulling or
unplugging the Welder. Keep the
Cord away from heat, oil, sharp
edges or moving parts. Damaged or
entangled Cords increase the risk of
electric shock.
Personal safety3.
Stay alert, watch what you are do-a.
ing and use common sense when
operating the Welder. Do not use
a power tool while you are tired or
under the inuence of drugs, alcohol
or medication. A moment of inatten-
tion while operating power tools may
result in serious personal injury.
Use safety equipment. Always wear b.
eye protection. Safety equipment
such as ANSI-approved/NIOSH-ap-
proved arc shaded, impact safety full
face shield, dust mask or respirator,
heavy-duty work gloves, non-skid
safety shoes, or hearing protection
used for appropriate conditions will
reduce personal injuries.
Avoid accidental starting. Ensurec.
the Power Switch (18) is in the off-
position before plugging in. Carrying
power tools with your nger on the
Switch or plugging in power tools
that have the Switch on invites ac-
cidents.
Remove any adjusting key or wrenchd.
before turning the Welder on. A
wrench or a key left attached to an
electrically charged part of the power
tool may result in personal injury.
Do not overreach. Keep proper foot-e.
ing and balance at all times. This
enables better control of the Welder
in unexpected situations.
Welder use and care4.
Do not force the Welder. Use thea.
correct power tool for your applica-
tion. The correct power tool will do
the job better and safer at the rate
for which it was designed.
Do not use the Welder if the Powerb.
Switch (18) does not turn it on and
off. Any power tool that cannot be
controlled with the Switch is danger-
ous and must be repaired prior to
use.
Disconnect the Power Cord Plugc.
(21) from the power source before
making any adjustments, changing
accessories, or storing power tools.
Such preventive safety measures
reduce the risk of starting the power
tool accidentally.
Store idle power tools out of thed.
reach of children and do not allow
persons unfamiliar with the Welder
or these instructions to operate the
power tool. Power tools are danger-
ous in the hands of untrained users.
Maintain the Welder. Check fore.
misalignment or binding of moving
parts, breakage of parts and any
other condition that may affect the
power tool’s operation. If damaged,
have the power tool repaired before
use. Many accidents are caused by
poorly maintained power tools.
Use the Welder and its accessoriesf.
in accordance with these instructions
and in the manner intended for the
particular type of power tool, taking
into account the working conditions

Page 5SKU 66042 For technical questions, please call 1-800-444-3353.
and the work to be performed. Use
of the Welder for operations different
from those intended could result in a
hazardous situation.
Service5.
Have your Welder serviced by aa.
qualied repair person using only
identical replacement parts. This will
ensure that the safety of the power
tool is maintained.
Specic Safety Rules
Ground this Welder. This Welder1.
requires the attachment and use of a
UL®listed, 230 volt, grounded,
3-prong, electrical Power Cord
Plug (not included). Only a quali-
ed electrician should install the
Power Cord Plug. Never remove the
grounding prong or modify the Plug
in any way. Do not use adapter plugs
with this product.
Maintain labels and nameplates on2.
the Welder. These carry important
safety information. If unreadable or
missing, contact Harbor Freight Tools
for a replacement.
Avoid electrical shock. Do not per-3.
mit electrically live parts, cables, or
electrodes to contact skin, clothing, or
gloves. Wear ANSI-approved protec-
tive clothing. This unit draws enough
current to cause serious injury or
death. Before turning the Welder on,
check the electrode holder to be sure
that there are no protruding screw
heads, and that all insulation is se-
cure. Do not weld unless you are
insulated from the ground and the
work piece.
Avoid eye and body damage. Arc4.
rays and infrared radiation can injure
eyes and burn skin. Wear ANSI ap-
proved eye and body protection. Do
not allow viewing by visitors without
proper eye and body protection. Use
a Face Shield with arc shaded lter
plate.
Move ammable and explosive mate-5.
rial at least 35 feet from the welding
arc to prevent sparks or molten metal
from starting a re. Keep a type ABC
re extinguisher within easy reach.
Thoroughly clean the workpiece of
any paint, grease, or other foreign
material.
Avoid unintentional starting. Prepare6.
to begin work before turning on the
Welder.
Do not leave the Welder unattended7.
when it is plugged into an electrical
outlet. Turn off the tool, and unplug it
from its electrical outlet before leav-
ing.
Use clamps (not included) or other8.
practical ways to secure and support
the work piece to a stable platform.
Holding the work by hand or against
your body is unstable and may lead
to loss of control.
This product is not a toy. Keep it out9.
of reach of children.
Industrial applications must follow10.
OSHA guidelines.
People with pacemakers should11.
consult their physician(s) before use.
Electromagnetic elds in close prox-
imity to heart pacemaker could cause
pacemaker interference or pacemak-
er failure. In addition, people with
pacemakers should:

Page 6SKU 66042 For technical questions, please call 1-800-444-3353.
• Avoid operating alone.
• Do not use with power switch locked
on.
• Properly maintain and inspect to
avoid electrical shock.
• Any power cord must be properly
grounded. Ground Fault Circuit Inter-
rupter (GFCI) should also be imple-
mented – it prevents sustained elec-
trical shock.
WARNING: This product, when used12.
for welding or similar applications,
produces chemicals known to the
State of California to cause cancer
and birth defects (or other reproduc-
tive harm). (California Health & Safe-
ty Code § 25249.5, et seq.)
13. Prevent eye injury and
burns. Wearing ANSI-ap-
proved personal safety
clothing and safety de-
vices reduce the risk for
injury.
Wear ANSI-approved safety impact•
eye goggles underneath welding
eye protection featuring at least a
Number 10 shade lens rating.
Leather leggings, re resistant •
shoes or boots should be worn
when using this product. Do not
wear pants with cuffs, shirts with
open pockets, or any clothing that
can catch and hold molten metal or
sparks.
Keep clothing free of grease, oil,•
solvents, or any ammable sub-
stances. Wear dry, insulating gloves
and protective clothing.
Wear an approved head covering•
to protect the head and neck. Use
aprons, cape, sleeves, shoulder
covers, and bibs designed and ap-
proved for cutting procedures.
When cutting overhead or in con-•
ned spaces, wear ame resistant
ear plugs or ear muffs to keep
sparks out of ears.
14. Prevent accidental res.
Remove any combustible
material from the work
area.
When possible, move the work to a•
location well away from combustible
materials. If relocation is not pos-
sible, protect the combustibles with
a cover made of re resistant mate-
rial.
Remove or make safe all combus-•
tible materials for a radius of 35 feet
(10 meters) around the work area.
Use a re resistant material to cover
or block all open doorways, win-
dows, cracks, and other openings.
Enclose the work area with por-•
table re resistant screens. Protect
combustible walls, ceilings, oors,
etc., from sparks and heat with re
resistant covers.
If working on a metal wall, ceiling,•
etc., prevent ignition of combus-
tibles on the other side by moving
the combustibles to a safe loca-
tion. If relocation of combustibles
is not possible, designate someone
to serve as a re watch, equipped
with a re extinguisher, during the
cutting process and for at least one
half hour after the welding is com-
pleted.
Do not weld on materials having a•
combustible coating or combustible
internal structure, as in walls or ceil-
ings, without an approved method
for eliminating the hazard.

Page 7SKU 66042 For technical questions, please call 1-800-444-3353.
Do not dispose of hot slag in con-•
tainers holding combustible materi-
als. Keep a re extinguisher nearby
and know how to use it.
After welding, make a thorough•
examination for evidence of re. Be
aware that easily-visible smoke or
ame may not be present for some
time after the re has started. Do
not weld in atmospheres contain-
ing dangerously reactive or am-
mable gases, vapors, liquids, and
dust. Provide adequate ventilation
in work areas to prevent accumula-
tion of ammable gases, vapors,
and dust. Do not apply heat to a
container that has held an unknown
substance or a combustible material
whose contents, when heated, can
produce ammable or explosive va-
pors. Clean and purge containers
before applying heat. Vent closed
containers, including castings, be-
fore preheating or welding.
Do not touch live electrical parts.15.
Wear dry, insulating gloves. Do not
touch electrode or conductor tong
with bare hand. Do not wear wet or
damaged gloves.
Protect yourself from electric shock.16.
Do not use outdoors. Insulate your-
self from the workpiece and ground.
Use nonammable, dry insulating
material if possible, or use dry rubber
mats, dry wood or plywood, or other
dry insulating material big enough to
cover your full area of contact with
the work or ground.
Always keep hoses and cables away17.
from the welding spot. Examine all
hoses and cables for cuts, burns, or
worn areas before each use. If any
damaged areas are found, replace
the hoses or cables immediately.
Read and understand all instructions18.
and safety precautions as outlined
in the manufacturer’s manual for the
material you will weld.
Use only the supplied Torch with this19.
Welder. Using components from
other systems may cause severe per-
sonal injury and damage components
within.
Ensure that the unit is placed on a20.
stable location before use. If this unit
falls while plugged in, severe injury,
electric shock, or re may result.
Avoid overexposure to fumes and21.
gases. Always keep your head out
of the fumes. Do not breathe the
fumes. Use enough ventilation or
exhaust, or both, to keep fumes and
gases from your breathing zone and
general area.
Where ventilation is questionable, •
have a qualied technician take
an air sampling to determine the
need for corrective measures. Use
mechanical ventilation to improve
air quality. If engineering controls
are not feasible, use an approved
respirator.
Follow OSHA guidelines for Permis-•
sible Exposure Limits (PEL’s) for
various fumes and gases.
Follow the American Conference•
of Governmental Industrial Hygien-
ists recommendations for Threshold
Limit Values (TLV’s) for fumes and
gases.
Have a recognized specialist in•
Industrial Hygiene or Environmental
Services check the operation and

Page 8SKU 66042 For technical questions, please call 1-800-444-3353.
air quality and make recommenda-
tions for the specic welding situa-
tion.
WARNING
INHALATION HAZARD:
Welding and Plasma Cutting Produce
TOXIC FUMES.
Exposure to welding or cutting
exhaust fumes can increase the risk
of developing certain cancers, such as
cancer of the larynx and lung cancer.
Also, some diseases that may be linked
to exposure to welding or plasma cutting
exhaust fumes are:
• Early onset of Parkinson’s Disease
• Heart disease • Ulcers
• Damage to the reproductive organs
• Inammation of the small intestine or
stomach • Kidney damage
• Respiratory diseases such as
emphysema, bronchitis, or pneumonia
Use natural or forced air ventilation and
wear a respirator approved by NIOSH to
protect against the fumes produced to
reduce the risk of developing the above
illnesses.
The warnings, precautions, and in-22.
structions discussed in this instruction
manual cannot cover all possible con-
ditions and situations that may occur.
It must be understood by the operator
that common sense and caution are
factors which cannot be built into this
product, but must be supplied by the
operator.
SAVE THESE INSTRUCTIONS.
SPECIFICATIONS
Electrical
Requirements
Input Voltage: 230 V~
60 Hz / Single Phase
Input Current: 26.0 Amps
Output Current: 130.0 Amps Max.
Output current
range
Duty Cycle:
100% @ 65.0 Amps
25% @ 130 Amps
Max. Open
Circuit Volt
(2-1/2 Min. ON per 10 minute
cycle
Power Cord
Plug
Required Power Cord Plug:
UL®Listed, Grounded, 3-Prong
(Not Included)
Material
Capacity 11 Gauge Steel Plate
Electrode Size Up to 1/8”
Cooling Method Fan Cooled
Accessories Electrode Holder (Qty. 1)
Ground Clamp (Qty. 1)
UNPACKING
When unpacking, check to make sure the
item is intact and undamaged. If nay parts
are missing or broken, please call Harbor
Freight Tools at the number shown on the
cover of this manual as soon as possible.
PRODUCT FEATURES
Ampere Selector (9):1. To regulate
the welding current.
(See Figure A, next page.)
Negative Terminal (11):2. Connect
the Ground Clamp (23) to this Termi-
nal. (See Figure A.)
Fault Indicator (12):3. Illumination of
the YELLOW Fault Indicator indicates
overheating caused by an excessive-
ly intense duty cycle. In this case,
stop welding and turn the Power
Switch OFF until the Fault Indica-
tor turns off. Then resume welding.
(See Figure A.)

Page 9SKU 66042 For technical questions, please call 1-800-444-3353.
Power Switch (18):4. The GREEN
(ON/OFF) Power Switch must illumi-
nate before welding operations can
be started. (See Figure A.)
Fan (19):5. The Fan must operate
continuously when operating the
Welder to prevent the unit from over-
heating. (See Figure A.)
Power Cord (21):6. Do not abuse the
Power Cord. Never use the Cord
for pulling or unplugging the Welder.
Keep the Cord away from heat, oil,
sharp edges or moving parts.
Positive Terminal (24):7. Connect the
Electrode Holder Cable (22) to this
Terminal. (See Figure A.)
ASSEMBLY INSTRUCTIONS
Read the ENTIRE IMPORTANT
SAFETY INFORMATION section
at the beginning of this manual
including all text under
subheadings therein before set
up or use of this product.
Note: For additional information regarding
the parts listed in the following pages,
refer to the Assembly Diagram near
the end of this manual.
TO PREVENT
SERIOUS INJURY
FROM ACCIDENTAL
OPERATION:
Turn the Power Switch (18) to
its off position and disconnect
the power cord from its
electric supply before
performing any assembly
procedures.
This Welder requires the attachment 1.
and use of a UL®-listed, 230 volt,
grounded, 3-prong, electrical Pow-
er Cord Plug (not included). Only a
qualied electrician should install the
Power Cord Plug. Never remove the
grounding prong or modify the Plug
in any way. Do not use adapter plugs
with this product.
Connect the Ground Clamp Cable2.
(23) to the Negative (--) Terminal (24).
(See Figure B.)
Connect the Electrode Holder Cable3.
(22) to the Positive (+) Terminal.
(See Figure B.)
WARNING
FIGURE A
21
12
24
11
9
18
19
FIGURE B
23
24
23
24
22

Page 10SKU 66042 For technical questions, please call 1-800-444-3353.
WORKPIECE AND WORK
AREA SET UP
Designate a work area that is clean1.
and well-lit. The work area must not
allow access by children or pets to
prevent injury and distraction.
The oor and surrounding area of 2.
your work site must not be am-
mable. A clean cement oor is rec-
ommended. The welding process
will eject molten metal slag onto the
oor, and it will scatter for 8 to 10 feet
or more in any direction. Have an
adequate re extinguisher available if
needed.
You must have a sturdy work table3.
that is open below the area you are
welding. Molten slag will be blown
through the workpiece, and must be
able to fall away freely.
Your work table must allow the work-4.
piece to be rmly clamped to prevent
it from accidentally moving or falling.
Route the Power Cord (21) along a5.
safe route to reach the work area
without creating a tripping hazard
or exposing the Power Cord to pos-
sible damage. The Power Cord must
reach the work area with enough
extra length to allow free movement
while working.
There must not be hazardous ob-6.
jects, such as utility lines or foreign
objects, nearby that will present a
hazard while working.
A barrier, such as a welding curtain7.
or welding shroud should be put up
to protect others in the work area and
limit the spray of sparks.
GENERAL OPERATING
INSTRUCTIONS
Protective gear
must be worn when
using the Welder.
ANSI-approved, arc shaded,
eye protection, a full face
shield, heavy-duty work
gloves, a welding apron,
respirator, and heavy-duty
work clothes without
pocketsshould be worn when
using this product. Do not
look at the ignited arc without
eye protection. Light from the
arc can cause permanent
damage to the eyes. Light
from the arc can burn the skin.
Do not breathe arc fumes.
The1. duty cycle denes the number
of minutes, within a 10 minute pe-
riod, during which a given Welder can
safely produce a particular current.
For example, this Welder, with a 100%
duty cycle at 65.0 Amps, means it
can operate continuously for 10 min-
utes at 65 Amps. Likewise, with a
25% duty cycle at 130 Amps means
the Welder can operate with rated
output for 2-1/2 minutes within a 10
minute working cycle. (See Figure C,
next page.)
DANGER

Page 11SKU 66042 For technical questions, please call 1-800-444-3353.
FIGURE C
Failure to carefully observe duty cy-•
cle limitations can stress a Welder’s
power generation system, contribut-
ing to premature Welder failure.
This Welder is equipped with an •
internal thermal protection system
to help prevent damage to the unit.
When the unit overheats; it auto-
matically shuts down, then returns
to service when it cools down.
Once the unit returns to service, fol-•
low a more conservative duty cycle
routine to help prevent excess wear
to the Welder.
Mount the metal to be welded to the2.
metal work table. It should be mount-
ed so that the welding debris falls to
the cement oor.
Place the Welder no closer than six3.
feet from the workpiece to be welded.
Securely attach the clamping end of4.
the Ground Clamp (23) to a part of
the workpiece or metal work table.
Place the bare end of the Electrode5.
(not included) in the Electrode Holder
(22). NOTE: Always keep the jaws
of the Electrode Holder clean to en-
sure proper electrical contact with the
Electrode.
Adjust the welding current with the6.
Ampere Selector (9). Thin metals
use low current and heavy metals use
high current.
Make sure the Power Switch (18) is7.
OFF. Then plug the Welder’s Power
Cord (21) into a dedicated, 230 volt,
grounded electrical outlet with delayed
action type circuit breaker or fuse.
While gripping the handle of the Elec-8.
trode Holder (22), with the Electrode
clear of grounded objects, turn the
Power Switch (18) ON.
Hold the Electrode Holder (22) rmly.9.
CAUTION! The Electrode Holder is
“live”. Direct the Electrode Holder
away from people and ammables.
WARNING: Never look at the ignited10.
arc without ANSI-approved, arc shad-
ed, eye protection in a full face shield.
Permanent eye damage or blindness
can occur. Skin burns can occur.
Wear a NIOSH-approved respirator to
avoid breathing arc fumes.
Stroke the area to be welded with the11.
Electrode to ignite the arc. Never tap
the Electrode into the welding surface
to ignite the arc. This damages its ex-
ternal coating on the Electrode which
prevents oxygen in the air from com-
ing into contact with the molten metal,
causing it to oxidize.
Once the arc is ignited, tilt the Elec-12.
trode forward at an angle of approxi-
mately 30° and hold it at a distance
from the welding object equal to the
diameter of the Electrode.
NOTE: If too much current is drawn13.
from the Welder, the built-in Thermal
Overload Protector will activate. The
YELLOW Fault Indicator (12) will

Page 12SKU 66042 For technical questions, please call 1-800-444-3353.
illuminate, and the Welder will auto-
matically shut off until it cools down.
If this happens, turn the Power Switch
(18) OFF and wait about ten minutes.
Then restart the Welder.
When the weld is complete, lift the14.
Electrode clearly away from any
grounded object. Then turn the
Power Switch (18) OFF.
Unplug the Power Cord (21) from the15.
electrical outlet.
Remove the Ground Clamp (23) from16.
the workpiece it is clamped onto.
Then remove the Electrode from the
Electrode Holder (22).
Allow all components of the Welder17.
to completely cool. Then clean and
store the Welder indoors out of reach
of children and other unauthorized
persons.
IMPORTANT: Refer to the included18.
“Weld Diagnoses” pamphlet for tips
and suggestions regarding proper
welding.
MAINTENANCE AND
SERVICING
Procedures not specically
explained in this manual
must be performed only by a
qualied technician.
TO PREVENT
SERIOUS INJURY
FROM ACCIDENTAL
OPERATION:
Turn the Power Switch (18) of
the Welder to its “OFF”
position and unplug the tool
from its electrical outlet before
performing any inspection,
maintenance, or cleaning
procedures.
TO PREVENT SERIOUS
INJURY FROM TOOL FAILURE:
Do not use damaged
equipment. If abnormal noise
or vibration occurs, have the
problem corrected before
further use.
BEFORE EACH USE, inspect the1.
general condition of the Welder.
Check for loose screws, misalignment
or binding of moving parts, cracked or
broken parts, damaged electrical wir-
ing, and any other condition that may
affect its safe operation.
AFTER USE,2. clean external surfaces
of the tool with a clean cloth.
PERIODICALLY3. , remove the Cover
(1) from the unit and, using com-
pressed air, blow out all dust and
debris from the interior.
4. WARNING! If the Power Cord (21)
of this Welder is damaged, it must be
replaced only by a qualied service
technician.
WARNING

Page 13SKU 66042 For technical questions, please call 1-800-444-3353.
TROUBLESHOOTING
230
230
PLEASE READ THE FOLLOWING CAREFULLY
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDED THE PARTS LIST AND ASSEMBLY
DIAGRAM IN THIS MANUAL AS A REFERENCE TOOL ONLY. NEITHER THE MANUFACTURER OR
DISTRIBUTOR MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT
HE OR SHE IS QUALIFIED TO MAKE ANY REPAIRS TO THE PRODUCT, OR THAT HE OR SHE IS
QUALIFIED TO REPLACE ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER AND/OR
DISTRIBUTOR EXPRESSLY STATES THAT ALL REPAIRS AND PARTS REPLACEMENTS SHOULD
BE UNDERTAKEN BY CERTIFIED AND LICENSED TECHNICIANS, AND NOT BY THE BUYER. THE
BUYER ASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR HER REPAIRS TO THE
ORIGINAL PRODUCT OR REPLACEMENT PARTS THERETO, OR ARISING OUT OF HIS OR HER
INSTALLATION OF REPLACEMENT PARTS THERETO.

Page 14SKU 66042 For technical questions, please call 1-800-444-3353.
PARTS LIST & ASSEMBLY DIAGRAM
Part # Description Qty. Part # Description Qty.
1 Cover 1 13 Indicator Base 1
2 Heat Sink 1 14 Base 1
3Rectier 1 15 IGBT 4
4 Main Control Board 1 16 Heat Sink 2
5 Transformer 1 17 Electric Temperature 1
6 Reactor 1 18 Power Switch 1
7 Heat Sink 1 19 Fan 1
8 Recovery Diode 4 20 Wire Tightener 1
9 Ampere Selector 1 21 Power Cord 1
10 Potentiometer 1 22 Electrode Holder 1
11 Negative Terminal 1 23 Ground Clamp 1
12 Fault Indicator 1 24 Positive Terminal 1
12 3 4
5
6
7
8
9, 10
11
12, 13
14
15
16
17
18
19
20, 21
24
Electrode Holder (22) not shown.
Ground Clamp (23) not shown.

Page 15SKU 66042 For technical questions, please call 1-800-444-3353.
ELECTRICAL SCHEMATIC

Page 16SKU 66042 For technical questions, please call 1-800-444-3353.
Record Product’s Serial Number Here:
Note: If product has no serial number, record month and year of purchase instead.
Note: Some parts are listed and shown for illustration purposes only, and are not avail-
able individually as replacement parts.
LIMITED 1 YEAR / 90 DAY WARRANTY
Harbor Freight Tools Co. makes every effort to assure that its products meet high
quality and durability standards, and warrants to the original purchaser that for a period
of ninety days from date of purchase that the torch, liner, wire feed mechanism (if ap-
plicable), welding clamps, electrode holders, cables and accessories packed with the
welder are free of defects in materials and workmanship. This Limited 90 Day/1 Year
Warranty shall not apply to consumable parts such as tips, welding wire, and gas
nozzles. Harbor Freight Tools also warrants to the original purchaser, for a period of
one year from date of purchase, that the transformer and rectier are free from defects
in materials and workmanship (90 days if used by a professional contractor or if used as
rental equipment). This warranty does not apply to damage due directly or indirectly to
misuse, abuse, negligence or accidents, repairs or alterations outside our facilities, nor-
mal wear and tear, or to lack of maintenance. We shall in no event be liable for death,
injuries to persons or property, or for incidental, contingent, special or consequential
damages arising from the use of our product. Some states do not allow the exclusion
or limitation of incidental or consequential damages, so the above limitation of exclu-
sion may not apply to you. THIS WARRANTY IS EXPRESSLY IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MER-
CHANTABILITY AND FITNESS.
To take advantage of this warranty, the product or part must be returned to us with
transportation charges prepaid. Proof of purchase date and an explanation of the com-
plaint must accompany the merchandise. If our inspection veries the defect, we will ei-
ther repair or replace the product at our election or we may elect to refund the purchase
price if we cannot readily and quickly provide you with a replacement. We will return re-
paired products at our expense, but if we determine there is no defect, or that the defect
resulted from causes not within the scope of our warranty, then you must bear the cost
of returning the product.
This warranty gives you specic legal rights and you may also have other rights
which vary from state to state.
3491 Mission Oaks Blvd. • PO Box 6009 • Camarillo, CA 93011 • [phone]