BOSSCO Mig 250 User manual

MODEL
•Inverter Mig 250
Operating Manual
(Owner’s Manual)
IMPORTANT: Read these instructions before installing, operating, or servicing this system.
First Edition
October, 2008Manual No. B0808

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BOSS Inverter Mig 250 Operating Manual
CONTENTS
SYMBOL LEGEND---------------------------------------------------------------------------------------------------2
STATEMENT OF WARRANTY------------------------------------------------------------------------------------3
1.0 GENERAL INFORMATION-------------------------------------------------------------------------------4
1.01 Notes, Cautions and Warnings------------------------------------------------------------------------4
1.02 Important Safety Precautions--------------------------------------------------------------------------4
1.03 Transporting methods-----------------------------------------------------------------------------------6
2.0 INSTALLATION RECOMMENDATION----------------------------------------------------------------7
2.01 Electrical Input Connections---------------------------------------------------------------------------8
2.02 Installation of MIG/MAG--------------------------------------------------------------------------------9
2.03 Specifications---------------------------------------------------------------------------------------------9
2.04 Duty Cycle------------------------------------------------------------------------------------------------10
3.0 OPERATOR CONTROLS-------------------------------------------------------------------------------11
3.01 Inverter Mig 250 Controls-----------------------------------------------------------------------------11
3.02 Inverter Mig 250 Control Methods------------------------------------------------------------------13
3.03 Weld Parameter Description-------------------------------------------------------------------------13
4.0 SET-UP FOR MIG/MAG---------------------------------------------------------------------------------14
5.0 POWER SUPPLY CONTROLS INDICATORS AND REATURES-----------------------------15
5.01 Basic MIG Welding Guide----------------------------------------------------------------------------16
5.02 Position of MIG GUN-----------------------------------------------------------------------------------16
5.03 Distance from the MIG Gun Nozzle to the Work Piece----------------------------------------16
5.04 Travel Speed---------------------------------------------------------------------------------------------16
5.05 Electrode Wire Size Selection-----------------------------------------------------------------------16
5.06 Spot Welding Operation-------------------------------------------------------------------------------17
6.0 MAINTENANCE--------------------------------------------------------------------------------------------18
7.0 BASIC TROUBLESHOOTING-------------------------------------------------------------------------18
7.01 Check the item and excrescent phenomenon exclusion method-----------------------------18
7.02 Solving Problems Beyond the Welding Terminals -----------------------------------------------20
7.03 Weld Problems--------------------------------------------------------------------------------------------22
7.04 Power Supply Problems--------------------------------------------------------------------------------23
8.0 PARTS LIST-------------------------------------------------------------------------------------------------24
9.0 REMARK-----------------------------------------------------------------------------------------------------28

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BOSS Inverter Mig 250 Operating Manual
SYMBOL LEGEND
AAmperage
Stick (SMAW)
VVoltage
Pulse Current Function
(GTAW)
Hz Hertz (frequency)
tSpot Time (GTAW)
SEC Seconds
Remote outputs control
(Panel/Remote)
%Percent
Remote Function
DC (Direct Current)
Arc Control (SMAW)
AC (Alternating Current)
t
2Gas Post-Flow Time
2T (GTAW)
t1Gas Pre-Flow Time
4T (GTAW)
VRD Voltage Reduction
Device Circuit
Repeat Function (GTAW)
—Negative
Spot Function (GTAW)
+Positive
High Frequency Starting
(GTAW)
Gas Input
Lift Start （GTAW）
Gas Output

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BOSS Inverter Mig 250 Operating Manual
STATEMENT OF WARRANTY
LIMITED WARRANTY: "BOSS" warrants to customers of its authorized distributors hereafter "BOSS" that its products will be
free of defects in workmanship or material. Should any failure to conform to this warranty appear within the time period
applicable to theBOSS products as stated below, BOSS shall, upon notification thereof and substantiation that the product has
been stored, installed, operated, and maintained in accordance withBOSS’sspecifications,instructions, recommendations and
recognized standard industry practice, and not subject to misuse, repair, neglect, alteration, or accident, correct such defects by
suitable repair or replacement, at BOSS ‘s sole option, of any components or parts of the product determinedby BOSS to be
defective.
The BOSS COMPANY MAKESNO OTHER WARRANTY,EXPRESS OR IMPLIED. THIS WARRANTY IS EXCLUSIVE AND
IN LIEU OF ALL OTHERS, INCLUDING, BUT NOT LIMITED TO ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULARPURPOSE.
LIMITATION OF LIABILITY: BOSS shall not under any circumstances be liable for special, indirect or consequential damages,
such as, but not limited to, lost profits and business interruption. The remedies of the Purchaser set forth herein are exclusive
and the liability of BOSS with respect to any contract, or anything done in connection therewith such as the performance or
breach thereof, or from the manufacture, sale, delivery, resale, or use of any goods covered by or furnished by BOSS whether
arising out of contract, negligence, strict tort, or under any warranty, or otherwise, shall not, except as expressly provided herein,
exceed the price of the goods upon which such liability is based. No employee, agent, or representative of BOSS is authorized
to change this warranty in any way or grant any other warranty.
PURCHASER'S RIGHTS UNDER THIS WARRANTY ARE VOID IF REPLACEMENT PARTS OR ACCESSORIES ARE USED
WHICH IN BOSS’S SOLE JUDGEMENT MAY IMPAIR THE SAFETY OR PERFORMANCE OF ANY BOSS PRODUCT.
PURCHASER'S RIGHTS UNDER THIS WARRANTY ARE VOID IF THE PRODUCT IS SOLD TO PURCHASER BY
NON-AUTHORIZED PERSONS.
The warranty is effective for the time stated below beginning on the date that the authorized distributor delivers the products to
the Purchaser. Notwith standing the foregoing, in no event shall the warranty period extend more than the time stated plus one
year from the dateBOSS delivered the product to the authorized distributor.
POWER SUPPLIES POWER SUPPLIES & WIRE FEEDERS
MAIN POWER MAGNETICS (STATIC& ROTATING) 1YEAR
ORIGINAL MAIN POWER RECTIFIER 1YEAR
POWER SWITCHING SEMI-CONDUCTORS & CONTROL PC BOARD 1YEAR
ALL OTHER CIRCUITS AND COMPONENTS INCLUDING 1YEAR
BUT NOT LIMITED TO, CONTACTORS, RELAYS,
SOLENOIDS, PUMPS, SWITCHES, MOTORS
Warranty repairs or replacement claims under this limited warranty must be submitted toBOSS by an authorizedBOSS repair
facility within thirty (30) days of purchaser’s notice of any Warranty Claim. No transportation costs of any kind willbe paid under
this warranty. Transportation charges to send products to an authorized warranty repair facility shall be the responsibility of the
Purchaser. All returned goods shall be at the Purchaser’s risk and expense. This warranty supersedes all previous BOSS
warranties.

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BOSS Inverter Mig 250 Operating Manual
1.0 GENERAL INFORMATION
1.01 Notes,Cautions and Warnings
Throughout this manual, notes, cautions, and warnings are used to highlight important information. These
highlights are categorized as follows:
NOTE
An operation, procedure, or background information which requires additional emphasis or is helpful in
efficient operation of the system.
CAUTION
A procedure which, if not properly followed, may cause damage to the equipment.
WARNING
A procedure which, if not properly followed, may cause injury to the operator or others in the operating area.
1.02 Important Safety Precautions
WARNING
OPERATION AND MAINTENANCE OF ARC WELDING EQUIPMENT CAN BE DANGEROUS AND
HAZARDOUS TO YOUR HEALTH.
To prevent possible injury, read, understand and follow all warnings, safety precautions and instructions
before using the equipment. Call your local distributor if you have any questions.
GASES AND FUMES
Gases and fumes produced during the Arc welding or cutting process can be dangerous and hazardous to
your health.
lKeep all fumes and gases from the breathing area. Keep your head out of the welding fume plume.
lUse an air-supplied respirator if ventilation is not adequate to remove all fumes and gases.
lThe kinds of fumes and gases from the arc welding/cutting depend on the kind of metal being used,
coatings on the metal, and the different processes. You must be very careful when cutting or welding
any metals which may contain one or more of the following:
Antimony Arsenic Barium Beryllium Cadmium Chromium Cobalt Copper Lead
ManganeseMercury Nickel Selenium Silver Vanadium
lAlways read the Material Safety Data Sheets (MSDS) that should be supplied with the material you
are using. These MSDSs will give you the information regarding the kind and amount of fumes and
gases that may be dangerous to your health.
lUse special equipment, such as water or down draft welding/cutting tables, to capture fumes and
gases.
lDo not use the welding torch in an area where combustible or explosive gases or materials are
located.
lPhosgene, a toxic gas, is generated from the vapors of chlorinated solvents and cleansers. Remove
all sources of these vapors.

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BOSS Inverter Mig 250 Operating Manual
ELECTRIC SHOCK
Electric Shock can injure or kill. The arc welding process uses and produces high voltage electrical energy.
This electric energy can cause severe or fatal shock to the operator or others in the workplace.
lNever touch any parts that are electrically “live” or “hot.”
lWear dry gloves and clothing. Insulate yourself from the work piece or other parts of the welding
circuit.
lRepair or replace all worn or damaged parts.
lExtra care must be taken when the workplace is moist or damp.
lInstall and maintain equipment according to NEC code, refer to relative standards
lDisconnect power source before performing any service or repairs.
lRead and follow all the instructions in the Operating Manual.
FIRE AND EXPLOSION
Fire and explosion can be caused by hot slag, sparks, or the arc weld.
lBe sure there is no combustible or flammable material in the workplace. Any material that cannot be
removed must be protected.
lVentilate all flammable or explosive vapors from the workplace.
lDo not cut or weld on containers that may have held combustibles.
lProvide a fire watch when working in an area where fire hazards may exist.
lHydrogen gas may be formed and trapped under aluminum workpieces when they are cut
underwater, or while using a water table. Donot cut aluminum alloys underwater or on a water table
unless the hydrogen gas can be eliminated or dissipated. Trapped hydrogen gas that is ignited will
cause an explosion.
NOISE
Noise can cause permanent hearing loss. Arc welding/cutting processes can cause noise levels to exceed
safe limits. You must protect your ears from loud noise to prevent permanent loss of hearing.
lTo protect your hearing from loud noise, wear protective ear plugs and/ or ear muffs. Protect others
in the workplace.
lNoise levels should be measured to be sure the decibels (sound) do not exceed safe levels.
ARC WELDING RAYS
Arc Welding/ Cutting Rays can injure your eyes and burn your skin. The arc welding/cutting process produces
very bright ultra violet and infra red light. These arc rays will damage your eyes and burn your skin if you are
not properly protected.
lTo protect your eyes, always wear a welding helmet or shield. Also always wear safety glasses with
side shields, goggles or other protective eye wear.
lWear welding gloves and suitable clothing to protect your skin from the arc rays and sparks.
lKeep helmet and safety glasses in good condition. Replace lenses when cracked, chipped or dirty.
lProtect others in the work area from the arc rays. Use protective booths, screens or shields.

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BOSS Inverter Mig 250 Operating Manual
1.03 Transporting methods
These units are equipped with a handle for carrying purposes.
WARNING: ELECTRIC SHOCK can kill.
DO NOT TOUCHlive electrical parts. Disconnect input power conductors from de-energized supply
line before moving the welding power source.
WARNING: FALLING EQUIPMENT can cause serious personal injury and
equipment damage.
lLift unit with handle on top of case.
lUse handcart or similar device of adequate capacity.
lIf using a fork lift vehicle, place and secure unit on a proper skid before transporting.

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BOSS Inverter Mig 250 Operating Manual
2.0 INSTALLATION RECOMMENDATION
Installation Environment
Inverter Mig 250 is designed for use in hazardous environments.
Examples of environments with increased hazardous environments are-
In locations in which freedom of movement is restricted, so that the operator is forced to perform the work
in a cramped (kneeling, sitting or lying) position with physical contact with conductive parts; In locations which
are fully or partially limited by conductive elements, and in which there is a high risk of unavoidable or
accidental contact by the operator, or in wet or damp hot locations where humidity or perspiration
considerable reduces the skin resistance of the human body and the insulation properties of accessories.
Environments with hazardous environments do not include places where electrically conductive parts in
the near vicinity of the operator, which can cause increased hazard, have been insulated.
Installation Location
Be sure to locate the welder according to the following guidelines:
lIn areas, free from moisture and dust.
lIn areas, free from oil, steam and corrosive
gases.
lIn areas, not exposed to direct sunlight or rain.
lAmbient temperature: between -10 degrees C
to 40 degrees C.
lIn areas, not subjected to abnormal vibration or
shock.
lPlace at a distance of 304.79mm or more from
walls or similar that could restrict natural airflow
for cooling.
WARNING 1
BOSS advises that this equipment be electrically connected by a qualified electrician.
The following Primary Current recommendations are required to obtain the maximum welding current and
duty cycle from this Power Supply:
Model Primary supply
lead size Minimum primary current circuit size Current & Duty Cycle
Inverter Mig 250 Minimum 8.0mm2
220V/ 46.3A
240V/ 42.4A 250A/26.5V@60% 200A/24V@100%
Table 1 Primary current circuit sizes to achieve maximum current

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BOSS Inverter Mig 250 Operating Manual
2.01 Electrical Input Connections
WARNING: ELECTRIC SHOCK can kill; SIGNIFICANT DC VOLTAGE is present
after removal of input power.
DO NOT TOUCH live electrical parts
SHUT DOWN welding power source, disconnect input power employing lockout/ tagging procedures.
Lockout/ tagging procedures consist of padlocking line disconnect switch in open position, removing fuses
from fuse box, or shutting off and red-tagging circuit breaker or other disconnecting device.
Electrical Input Requirements
Operate the welding power source from a single phase 50/ 60 Hz, AC power supply. The input voltage must
match one of the electrical input voltages shown on the input data label on the unit nameplate. Contact the
local electric utility for information about the type of electrical service available, how proper connections
should be made, and inspection required.
The line disconnect switch provides a safe and convenient means to completely remove all electrical power
from the welding power supply whenever necessary to inspect or service the unit.
According to Table 1 and below as a guide to select line fuses for the disconnect switch.
Input Voltage Fuse Size
220/240V AC 60 Amps
Table 2
Notice: Fuse size is based on not more than 200 percent of the rated input amperage of the
welding power source (Based on Article 630, National Electrical Code).
Figure 1 Electrical input connections

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BOSS Inverter Mig 250 Operating Manual
2.02 Installation of MIG/MAG
lConnect the work lead to negative (-) socket (positive (+) for special wire).
lConnect the gun lead to the positive (+) socket (negative(-) for special wire).
lPosition a gas cylinder on the rear tray and lock securely to the power supply cylinder bracket with the
chain provided. If this arrangement is not used then ensure that the gas cylinder is secured to a
building pillar, wall bracket or otherwise securely fixed in an upright position.
lFit the gas regulator/ flowmeter to the gas cylinder (choose different gas according to wire: CO2,
mixed gas, argon and so on).
lOne dual groove feed rollers are supplied as standard with the power supply. These can
accommodate 0.8mm and 1.0mm diameter hard wires. Select the roller required with the chosen wire
size marking facing outwards.
lFit the electrode wire spool to the wire reel hub.
lLift up the wire feeder pressure lever and lift the electrode wire to the entrance of the gun.
lLower the pressure lever and with the gun lead reasonably straight, feed the wire through the gun, till
to extend from the hole in the middle of contact tip.
lRegulate the current, voltage to the value required according to the thickness of work piece (short
circuit transition, dip transition, and spray transition can be produced according to different regulated
current , voltage).
lInstall appropriately, there is no faulty after inspecting, you can start welding.
2.03 Specifications
MODEL Inverter Mig 250
Input voltage and frequency and phases 220/240V 50/60Hz 1ph
KVA @ max output 10KVA
Max current 250A
Output current range 30~250A
Open circuit voltage 62/68V
Duty cycle at 40℃60%
Weight 40Kg
Dimensions 580×350×410
Table 3

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BOSS Inverter Mig 250 Operating Manual
2.04 Duty Cycle
The duty cycle of a welding power source is the percentage of a ten (10) minute period that it can be
operated at a given output without causing overheating and damage to the unit. If the welding amperes
decrease, the duty cycle increases. If the welding amperes are increased beyond the rated output, the duty
cycle will decrease.
WARNING: Exceeding the duty cycle ratings will cause the thermal overload
protection circuit to become energized and shut down the output until has cooled
to normal operating temperature
Continually exceeding the duty cycle ratings
can cause damage to the welding power source.
NOTICE：
Due to variations that can occur in manufacture products, claimed performance, voltages, ratings, all
capacities, measurements, dimensions and weights quoted are approximate only. Achievable capacities and
ratings in use and operation will depend upon correct installation, use, applications, maintenance and service.

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BOSS Inverter Mig 250 Operating Manual
3.0 OPERATOR CONTROLS
3.01 Inverter Mig 250 controls
Figure 2
1. Main Circuit Bleaker—Switching to the ON position energizes the welding power source.
2. Selector Control—2T/ Spot/ 4T
3. Spot Time
4. 14-Pin Receptacle—Used to connect the wire feeder.
5. Wire Feed Speed Control.
6. Voltage Control.
7. Positive Terminal—50mm Screw receptacle.
8. Negative Terminal—50mm Screw receptacle.
9. Terminal—Use to connect the torch.
10. Down Slope Voltage Control (Optional).
11. Down Slope Amperage Control (Optional).
12. Meter Selection.
13. Inductance Control (Inside).
14. Digital Meter.
15. Warning Indicator—Activates under the following conditions:
•Input voltage is too low/ too high
•Thermal overload
16. AC Power Indicator—Lights when in the ON position.
17. Ground.
18. Input Power Cable Port.
19. 110VAC Auxiliary Power.
20. Fuse.
21. Input Gas Fitting.
22. Burnback (Inside).

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BOSS Inverter Mig 250 Operating Manual
Figure 3
Pin WF2 function 4 inch spool gun function
ATorch switch input Torch switch input
BTorch switch input Torch switch input
CCurrent regulation
DCurrent regulation
ECurrent regulation
FShort line Short line
GShort line Short line
HShort line
ISpot switch
JSpot switch
KSolenoid valve
LSolenoid valve
MWF2 motor Spool gun motor
NWF2 motor Spool gun motor
Table 4
WARNING
When the welder is connected to the primary supply voltage, the internal electrical
components maybe at primary potential with respect to earth.

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BOSS Inverter Mig 250 Operating Manual
3.02 Inverter Mig 250 Control Methods
Weld Control MIG/MAG Description
2T Mode Yes 2T mode MIG
4T Mode Yes 4T mode MIG
Spot mode Yes Spot mode MIG
Table 5 Inverter Mig 250 selection of weld technology in different weld methods
3.03 Weld parameter description
Figure 4 Inverter Mig 250 front panel with parame ter description
Parameter Description
Welding Current
This parameter sets the welding current.
Spot Time MIG only. The welding current can be set, and be controlled according to the setting
time. This mode of welding is used to melt the top & bottom plates together to form a
nugget between them.
Burnback Time MIG only. Burnback time is the difference between the wire feed motor stopping and
switching off of the welding current. The Burnback time allows the electrode wire to
burn out of the molten metal weld pool, to separate the electrode wire from work piece.
Table 6 Weld parameter description forInverter Mig 250

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BOSS Inverter Mig 250 Operating Manual
4.0 SET-UP FOR MIG/MAG
Conventional operating procedures apply when using the welding power source, i.e. connect work lead
directly to work piece and connect MIG gun to the power source. Wide safety margins provided by the coil
design ensure that the welding power source will withstand short-term overload without adverse effects. The
welding current range values should be used as a guide only. Current delivered to the arc is dependent on the
welding arc voltage, and as welding arc voltage varies between different classes of electrodes, welding
current at any one setting would vary according to the type of electrode in use. The operator should use the
welding current range values as a guide, and then finally adjust the current setting to suit the application.
Figure 5Set up for Inverter Mig 250
WARNING:
Before connecting the work clamp to the work and inserting the electrode in the electrode holder
make sure the Primary power supply is switched off.
CAUTION 2:
Remove any packaging material prior to use. Do not block the air vents at the front or rear of the
Welding Power Source.

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BOSS Inverter Mig 250 Operating Manual
5.0 POWER SUPPLY CONTROLS INDICATORS AND REATURES
Figure 6Inverter Mig 250 front panel
1. Main Power Switch.
2. Mode Selector Switch 2T/ Spot/ 4T
3. Spot Time Control (a spot welding nozzle required).
4. 14-Pin Receptacle—Used to connect the wire feeder.
5. Wire Feed Speed Control.
6. Voltage Control.
7. Down Slope Amperage Control (Optional).
8. Down Slope Voltage Control (Optional).
9. Meter Selection.
10. Voltage Indicator.
11. Speed Indicator.
12. Amperage Indicator.
13. Digital Meter.
14. Warning Indicator.
15. AC Power indicator.

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BOSS Inverter Mig 250 Operating Manual
5.01 Basic MIG Welding Guide
The welding power supply has two control settings that have to balance. These are the wire speed
control and the voltage control switches. The welding current is determined by the wire speed control, the
current will increase with increased wire speed, resulting in a shorter arc. Less wire speed will reduce the
current and lengthen the arc. By decreasing the voltage, a shorter arc is obtained with little change in welding
current, because the wire speed is not changed.
lWhen changing to a different electrode wire diameter, different control settings are required. Athinner
electrode wire needs more wire speed to achieve the same current level.
lA satisfactory weld cannot be obtained if the wire speed and voltage switch settings are not adjusted to
suit the electrode wire diameter and dimensions of the work piece.
lIf the wire speed is too high for the welding voltage, “stubbing”will occur as the wire dips into the molten
pool. If the wire speed is too slow for the welding voltage, large drops will form on the end of the
electrode wire, causing spatter. Suppose that wire speed is constant, if the welding voltage is too high,
large drops will form on the end of the electrode wire, causing spatter; if the voltage is too low, the wire
will not melt.
5.02 Position of MIG Gun
The angle of MIG gun to the weld has an effect on the width of the weld run.
Figure 7MIG gun angle
5.03 Distance from the MIG Gun Nozzle to the Work Piece
The electrode stick out from the MIG gun nozzle should be between 2.0mm to 5.0mm. This distance may
vary depending on the type of joint that is being weld.
5.04 Travel Speed
Speed at which a weld travels influences the width of the weld and penetration of the welding run.
5.05 Electrode Wire Size Selection
The choice of electrode wire size in conjunction with shielding gas used depends on:

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BOSS Inverter Mig 250 Operating Manual
lThickness of the metal to be welded.
lType of joint.
lCapacity of the wire feed unit and power supply.
lThe amount of penetration required.
lThe deposition rate required.
lThe bead profile desired
lThe position of welding and cost of the electrode wire.
Weld metal deposition rate is proportional to current density. Current density is defined as the current per
cross sectional area of electrodewire and is normally expressed as amps per mm2. An example is tabled
below.
Electrode Wire Size
Current (A)Current Density (A/mm2)Deposition Rate (lbs/hour)
0.9mm (.035”) 200 314 7.0
1.2mm (.045”) 200 177 6.2
Table 70.9mm/ 1.2mm wire deposition rate
This demonstrates that where the upper limit of current is limited by the machine capacity and duty cycle,
higher deposition rates therefore greater productivity will be achieved by using smaller electrode wire. The
Inverter Mig 250 is a particularity efficient MIG welder with the 0.9mm~1.2mm steel wire in spray transfer
mode. 0.9mm wire cost approx. 10% more than 1.2mm but is deposited approx 15% faster.
High current density or smaller diameter wire also gives deeper penetration as shown:
Figure 8 Wire penetration comparison
5.06 Spot Welding Operation
Fit a spot welding nozzle to the MIG gun for consistent spot welding operations. The Inverter Mig 250
power supply will operate effectively using 0.8~1.2mm electrode wire when spot welding. Penetration depth is
limited when using 0.6mm electrode wire for spot welding. Set the controls as follows for spot welding:
1．Coarse & fine voltage selector switches and wire speed control.
Select higher voltage selector switch positions and set the wire speed control between 354 to 590ipm
(9~15 meters/ minute)
2．Mode selector switch.
3．Spot Time.
4．Burnback Time.

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BOSS Inverter Mig 250 Operating Manual
6.0 MAINTENANCE
If this equipment does not operate properly, stop work immediately and investigate the cause of the
malfunction. Maintenance work must be performed by an experienced, qualified person only. Any electrical
work must be performed by an electrician or other person properly trained in servicing electrical equipment.
Do not permit untrained persons to inspect, clean or repair this equipment. Use only recommended
replacement parts when servicing this machine.
Periodically clean the inside of the welding power source by using clean dry compressed air of not over
25psi as normal preventive maintenance. At the time of the cleaning, a full inspection of the welding machine
and setup should be performed. Check warning labels on the machine for readability; replace if necessary.
Check input and output connections as well as frame ground connections to the machine to insure that they
are tight and the wires are not frayed or overheated. Inspect internal wiring of machine for loose or frayed
connections; tighten or repair as necessary. It would also be advisable to check connections to wire feeders,
fixtures, etc., at this time. Any damaged cable or hoses should be replaced.
DANGER: HIGH VOLTAGE is present internally even with the control power switch in the
OFF position. Before inspecting, cleaning, or servicing, disconnect and lock out input power to
the power source.
7.0 BASIC TROUBLESHOOTING
WARNING
There are extremely dangerous voltages and power levels present inside this product.
Do not attempt to open or repair unless you are an accredited BOSS service agent and
you have had training in power measurements and troubleshooting techniques.
If major complex subassemblies are faulty, then the welding power source must be returned to an
accredited BOSS service agent for repair.
The basic level of troubleshooting is that which can be performed without special equipment or
knowledge.
7.01 Check the item and excrescent phenomenon exclusion method