MK 280/281/282/283 Cobra MX Miller Com ACWC Owner Manual

Shown with Classic Cup

Millermatic Compatible

™

Owner’s Manual

Product: Cobra ® MX

Millermatic

Manual:

Serial:

091-0628

13020001

Voltage Rating: 24 VDC

Revision: Feb 2013 Rev D

Gun models: 280-8xx A/C 1/4"

281-8xx A/C 3/8"

282-8xx W/C 1/4"

283-8xx W/C 3/8"

Shown with MAX Cup

175 Ampere Air Cooled, 1/4" tip

200 Ampere Air Cooled, 3/8" tip

225 Ampere Water Cooled, 1/4" tip

250 Ampere Water Cooled, 3/8" tip

P u s h - P u l l W e l d i n g G u n s

Table of Contents

Safety Considerations ........................................................................i-iii

Installation ............................................................................... Section A

Technical Specifications .....................................................................................1

Support Equipment Required .............................................................................1

Coolant Recommendations ................................................................................1

Gun Lead Connections ......................................................................................1

Operation .................................................................................Section B

General ..............................................................................................................2

Controls and Settings .........................................................................................2

Trigger Adjustment .............................................................................................2

Drive Roll and Idler Rolls....................................................................................3

Accessories .............................................................................Section C

Optional Kits .......................................................................................................4

Conduits .............................................................................................................4

Snake Skins .......................................................................................................4

Contact Tips .......................................................................................................5

Gas Cups ...........................................................................................................6

Maintenance ............................................................................Section D

Periodic Maintenance.........................................................................................6

Recommended Spare Parts List ........................................................................7

Troubleshooting .......................................................................Section E

Troubleshooting Guide .......................................................................................9

Testing the Gun ..................................................................................................9

Appendices .............................................................................. Section F

Diagrams / Parts List ........................................................................................ 11

Mechanical .......................................................................................................12

Electrical...........................................................................................................29

Safety Warnings

Warranty

Declaration of Conformity for

European Community (CE) Products

Note

This information is provided for units with CE certification (see rating label on unit).

Manufacturer’s Name:

MK Products, Inc.

16882 Armstrong Ave.

Irvine, CA 92606

Declares that the product:

Cobra

®

MX Millermatic Compatible

conforms to the following Directives and Standards:

Directives

Low Voltage Directive: 2006/95/EC

Electromagnetic Compatibility (EMC) Directive: 2004/108/EC

Standards

Electromagnetic Compatibility, (EMC): EN 60974-10: 2007

Torches And Guns For Arc Welding, EN 60974-7: 2005

SAFETy CONSIDERATIONS

ELECTRIC ARC WELDING EQUIPMENT

CAUTION : READ BEFORE ATTEMPTING INSTALLATION, OPERATION

OR MAINTENANCE OF THIS EQUIPMENT

1-1 INTRODUCTION

This equipment is intended for ultimate application by commercial/industrial users and for operation by persons trained and experienced in the use and maintenance of welding equipment.

Operation should not be undertaken without adequate training in the use of such equipment. Training is available from many public and private schools or similar facilities.

Safe practices in the installation, operation and maintenance of this equipment requires proper training in the art, a careful study of the information provided with the equipment, and the use of common sense. Rules for safe use are generally provided by suppliers of welding power sources, compressed gas suppliers, and electrode suppliers.

Careful compliance with these rules will promote safe use of this equipment.

The following Safety Rules cover some of the more generally found situations.

READ THEM CAREFULLY. In case of any doubt, obtain qualified help before proceeding.

1-2 GENERAL PRECAUTIONS

A. Burn Prevention

ELECTRIC ARC WELDING PRODUCES

H I G H I N T E N S I T Y H E AT A N D

ULTRAVIOLET RADIANT ENERGY

WHICH MAY CAUSE SERIOUS AND

PERMANENT EYE DAMAGE AND

WHICH MAY DAMAGE ANY EXPOSED

SKIN AREAS.

Wear helmet with safety goggles or glasses with side shields underneath, appropriate filter lenses or plates

(protected by clear cover glass). This is a must for welding or cutting (and chipping) to protect the eyes from radiant energy and flying metal. Replace cover glass when broken, pitted, or spattered.

Medical first aid and eye treatment. First aid facilities and a qualified first aid person should be available for each shift unless medical facilities are close by for immediate treatment of flash burns of the eyes and skin burns.

Wear protective clothing - leather (or asbestos) gauntlet gloves, hat, and high safety-toe shoes. Button shirt collar and pocket flaps, and wear cuffless trousers to avoid entry of sparks and slag.

Avoid oily or greasy clothing. A spark may ignite them.

Flammable hair preparations should not be used by persons intending to weld or cut.

Hot metal such as electrode stubs and work pieces should never be handled without gloves.

Ear plugs should be worn when working on overhead or in a confined space. A hard hat should be worn when others work overhead.

B. Toxic Fume Prevention

WARNING: The use of this product may result in exposure to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

Adequate ventilation. Severe discomfort, illness or death can result from fumes, vapors, heat, or oxygen enrichment or depletion that welding (or cutting) may produce. Prevent them with adequate ventilation. NEVER ventilate with oxygen.

Lead-, cadmium-, zinc-, mercury-, beryllium-bearing and similar materials, when welded or cut, may produce harmful concentrations of toxic fumes.

Adequate local exhaust ventilation must be used, or each person in the area, as well as the operator, must wear an air-supplied respirator. For beryllium, both must be used.

Metals coated with or containing materials that emit toxic fumes should not be heated unless coating is removed form the work surface, the area is well ventilated, or the operator wears an air-supplied respirator.

Work in a confined space only while it is being ventilated and, if necessary, while wearing an air-supplied respirator.

Gas leaks in a confined space should be avoided. Leaked gas in large quantities can change oxygen concentration dangerously. Do not bring gas cylinders into a confined space.

Leaving confined space, shut OFF gas supply at source to prevent possible accumulation of gases in the space if downstream valves have been accidentally opened or left open. Check to be sure that the space is safe before reentering it.

Vapors from chlorinated solvents can be decomposed by the heat of the arc

(or flame) to form PHOSGENE, a highly toxic gas, and other lung and eye irritating products. The ultraviolet (radiant) energy of the arc can also decompose trichloroethylene and perchloroethylene vapors to form phosgene. DO NOT

WELD or cut where solvent vapors can be drawn into the welding or cutting atmosphere or where the radiant energy can penetrate to atmospheres containing even minute amounts of trichloroethylene or perchloroethylene.

C. Fire and Explosion Prevention

Causes of fire and explosion are: combustibles reached by the arc, flame, flying sparks, hot slag, or heated material, misuse of compressed gases and cylinders, and short circuits.

BE AWARE THAT flying sparks or falling slag can pass through cracks, along pipes, through windows or doors, and through wall or floor openings, out of sight of the goggled operator. Sparks can fly many feet.

To prevent fires and explosion:

Keep equipment clean and operable, free of oil, grease, and (in electrical parts) of metallic particles that can cause short circuits.

If combustibles are in area, do NOT weld or cut. Move the work if practicable, to an area free of combustibles. Avoid paint spray rooms, dip tanks, storage areas, ventilators. If the work cannot be moved, move combustibles at least

35 feet away, out of reach of sparks and heat; or protect against ignition with suitable and snug-fitting, fire-resistant covers or shields.

Walls touching combustibles on opposite sides should not be welded on (or cut).

Walls, ceilings, and floor near work should be protected by heat-resistant covers or shields.

Fire watcher must be standing by with suitable fire extinguishing equipment during and for some time after welding or cutting if:

1. Appreciable combustibles (including building construction) are within 35 feet.

2. Appreciable combustibles are further than 35 feet, but can be ignited by sparks.

3. Openings (concealed or visible) in floors or walls within 35 feet may expose combustibles to sparks.

4. Combustibles adjacent to walls, ceilings, roofs, or metal partitions can be ignited by radiant or conducted heat.

Hot work permit should be obtained before operation to ensure supervisor’s approval that adequate precautions have been taken.

After work is done, check that area is free of sparks, glowing embers, and flames.

A n e m p t y c o n t a i n e r t h a t h e l d combustibles, or that can produce flammable or toxic vapors when heated, must never be welded on or cut, unless container has first been cleaned in accordance with industry standards.

This includes: a thorough steam or caustic cleaning (or a solvent of water washing, depending on the combustible’s solubility), followed by purging and inerting with nitrogen or carbon dioxide, and using protective equipment.

Water-filling just below working level may substitute for inerting.

A container with unknown contents should be cleaned (see paragraph above). Do NOT depend on sense of smell or sight to determine if it is safe to weld or cut.

Hollow castings or containers must be vented before welding or cutting. They can explode.

Explosive atmospheres. NEVER weld or cut where the air may contain flammable dust, gas, or liquid vapors (such as gasoline).

D. Compressed Gas Equipment

The safe handling of compressed gas equipment is detailed in numerous industry publications. The following

Cobra ®

MX Millermatic Compatible™ Owner's Manual - Page i

general rules cover many of the most common situations.

1. Pressure Regulators

Regulator relief valve is designed to protect only the regulator from overpressure; it is not intended to protect any downstream equipment. Provide such protection with one or more relief devices.

Never connect a regulator to a cylinder containing gas other than that for which the regulator was designed.

Remove faulty regulator from service immediately for repair (first close cylinder valve). The following symptoms indicate a faulty regulator:

Leaks - if gas leaks externally.

Excessive Creep - if delivery pressure continues to rise with downstream valve closed.

Faulty Gauge - if gauge pointer does not move off stop pin when pressurized, nor returns to stop pin after pressure release.

Repair. Do NOT attempt repair. Send f a u l t y r e g u l a t o r s f o r r e p a i r t o manufacturer’s designated repair center, where special techniques and tools are used by trained personnel.

2. Cylinders

Cylinders must be handled carefully to prevent leaks and damage to their walls, valves, or safety devices:

Avoid electrical circuit contact with cylinders including third rails, electrical wires, or welding circuits. They can produced short circuit arcs that may lead to a serious accident. (See 1-3C)

ICC or DOT marking must be on each cylinder. It is an assurance of safety when the cylinder is properly handled.

Identifying gas content. Use only cylinders with name of gas marked on them; do not rely on color to identify gas content. Notify supplier if unmarked.

NEVER DEFACE or alter name, number, or other markings on a cylinder. It is illegal and hazardous.

Empties: Keep valves closed, replace caps securely; mark MT; keep them separate from FULLS, and return promptly.

Prohibited use. Never use a cylinder or its contents for other than its intended use,

NEVER as a support or roller.

Locate or secure cylinders so they cannot be knocked over.

Passageways and work areas. Keep cylinders clear of areas where they may be stuck.

Transporting cylinders. With a crane, use a secure support such as a platform or cradle. Do NOT lift cylinders off the ground by their valves or caps, or by chains, slings, or magnets.

Do NOT expose cylinders to excessive heat, sparks, slag, and flame, etc. that may cause rupture. Do not allow contents to exceed 55 degrees C (130 degrees

F.) Cool with water spray where such exposure exists.

Protect cylinders, particularly valves from bumps, falls, falling objects, and weather. Replace caps securely when moving cylinders.

Stuck valve. Do NOT use a hammer or wrench to open a cylinder valve that cannot be opened by hand. Notify your supplier.

Mixing gases. NEVER try to mix any gases in a cylinder.

NEVER refill any cylinder.

Cylinder fittings should never be modified or exchanged.

3. Hose

Prohibited use. Never use hose other than that designed for the specified gas.

A general hose identification rule is: red for fuel gas, green for oxygen, and black for inert gases.

Use ferrules or clamps designed for the hose (not ordinary wire or other substitute) as a binding to connect hoses to fittings.

No copper tubing splices. Use only standard brass fittings to splice hose.

Avoid long runs to prevent kinks and abuse. Suspend hose off ground to keep it from being run over, stepped on, or otherwise damaged.

Coil excess hose to prevent kinks and tangles.

Protect hose from damage by sharp edges, and by sparks, slag, and open flame.

Examine hose regularly for leaks, wear, and loose connections. Immerse pressured hose in water; bubbles indicate leaks

Repair leaky or worn hose by cutting area out and splicing. Do NOT use tape.

4. Proper Connections

Clean cylinder valve outlet of impurities that may clog orifices and damage seats before connecting regulator. Except for hydrogen, crack valve momentarily, pointing outlet away from people and sources of ignition. Wipe with a clean, lintless cloth.

Match regulator to cylinder. Before connecting, check that the regulator label and cylinder marking agree, and that the regulator inlet and cylinder outlet match. NEVER Connect a regulator designed for a particular gas or gases to a cylinder containing any other gas.

Tighten connections. When assembling threaded connections, clean and smooth seats where necessary. Tighten. If connection leaks, disassemble, clean, and retighten, using properly fitting wrench.

Adapters. Use a CGA adapter (available from your supplier) between cylinder and regulator, if one is required. Use two wrenches to tighten adapter marked

RIGHT and LEFT HAND threads.

Regulator outlet (or hose) connections may be identified by right hand threads for oxygen and left hand threads (with grooved hex on nut or shank) for fuel gas.

5. Pressurizing Steps:

Drain regulator of residual gas through suitable vent before opening cylinder

(or manifold valve) by turning adjusting screw in (clockwise). Draining prevents excessive compression heat at high pressure seat by allowing seat to open on pressurization. Leave adjusting screw engaged slightly on single-stage regulators.

Stand to side of regulator while opening cylinder valve.

Open cylinder valve slowly so that regulator pressure increases slowly.

When gauge is pressurized (gauge reaches regulator maximum) leave cylinder valve in following position: for oxygen and inert gases, open fully to seal stem against possible leak; for fuel gas, open to less than one turn to permit quick emergency shut-off.

Use pressure charts (available from your supplier) for safe and efficient recommended pressure settings on regulators.

Check for leaks on first pressurization and regularly thereafter. Brush with soap solution. Bubbles indicate leaks.

Clean off soapy water after test; dried soap is combustible.

E. User Responsibilities

Follow all Safety Rules.

Remove leaky or defective equipment from service immediately for repair. Read and follow user manual instructions.

F. Leaving Equipment Unattended

Close gas supply at source and drain gas.

G. Rope Staging-Support

Rope staging-support should not be used for welding or cutting operation; rope may burn.

1-3 ARC WELDING

Comply with precautions in 1-1, 1-2, and this section. Arc Welding, properly done, is a safe process, but a careless operator invites trouble. The equipment carries high currents at significant voltages.

The arc is very bright and hot. Sparks fly, fumes rise, ultraviolet and infrared energy radiates, weldments are hot, and compressed gases may be used.

The wise operator avoids unnecessary risks and protects himself and others from accidents.

A. Burn Protection

Comply with precautions in 1-2.

The welding arc is intense and visibly bright. Its radiation can damage eyes, penetrate lightweight clothing, reflect from light-colored surfaces, and burn the skin and eyes. Skin burns resemble

Cobra ®

MX Millermatic Compatible™ Owner's Manual - Page ii

acute sunburn; those from gas-shielded arcs are more severe and painful.

DON’T GET BURNED; COMPLY WITH

PRECAUTIONS.

1. Protective Clothing

Wear long-sleeve clothing in addition to gloves, hat, and shoes. As necessary, use additional protective clothing such as leather jacket or sleeves, flameproof apron, and fire-resistant leggings. Avoid outer garments of untreated cotton.

Bare skin protection. Wear dark, substantial clothing. Button collar to protect chest and neck, and button pockets to prevent entry of sparks.

2. Eye and Head Protection

Protect eyes from exposure to arc. Eyes may be damaged by radiant energy when exposed to the electric arc, even when not looking in the direction of the arc. Never look at an electric arc without protection.

Welding helmet or shield containing a filter plate shade no. 12 or denser must be used when welding. Place over face before striking arc.

Protect filter plate with a clear cover plate.

Cracked or broken helmet or shield should NOT be worn; radiation can be passed through to cause burns.

Cracked, broken, or loose filter plates must be replaced IMMEDIATELY.

Replace clear cover plate when broken, pitted, or spattered.

Flash goggles with side shields MUST be worn under the helmet to give some protection to the eyes should the helmet not be lowered over the face before an arc is struck. Looking at an arc momentarily with unprotected eyes (particularly a high intensity gas-shielded arc) can cause a retinal burn that may leave a permanent dark area in the field of vision.

3. Protection of Nearby Personnel

Enclose the welding area. For production welding, a separate room or enclosed bay is best. In open areas, surround the operation with low-reflective, noncombustible screens or panels. Allow for free air circulation, particularly at floor level.

Viewing the weld. Provide face shields for all persons who will be looking directly at the weld.

Others working in area. See that all persons are wearing flash goggles.

Before starting to weld, make sure that screen flaps or bay doors are closed.

B. Toxic Fume Prevention

Comply with precautions in 1-2B.

Generator engine exhaust must be vented to the outside air. Carbon monoxide can kill.

C. Fire and Explosion Prevention

Comply with precautions in 1-2C.

Equipment’s rated capacity. Do not overload arc welding equipment. It may overheat cables and cause a fire.

Loose cable connections may overheat or flash and cause afire.

Never strike an arc on a cylinder or other pressure vessel. It creates a brittle area that can cause a violent rupture or lead to such a rupture later under rough handling.

D. Compressed Gas Equipment

Comply with precautions in 1-2D.

E. Shock Prevention

Exposed electrically hot conductors or other bare metal in the welding circuit, or in ungrounded, electrically-HOT equipment can fatally shock a person whose body becomes a conductor. DO

NOT STAND, SIT, LIE, LEAN ON, OR

TOUCH a wet surface when welding without suitable protection.

To protect against shock:

Keep body and clothing dry. Never work in damp area without adequate insulation against electrical shock. Stay on a dry duckboard, or rubber mat when dampness or sweat cannot be avoided.

Sweat, sea water, or moisture between body and an electrically HOT part - or grounded metal - reduces the body surface electrical resistance, enabling dangerous and possibly lethal currents to flow through the body.

1. Grounding the Equipment

When installing, connect the frames of each unit such as welding power source, control, work table, and water circulator to the building ground. Conductors must be adequate to carry ground currents safely. Equipment made electrically HOT by stray currents may shock, possibly fatally. Do NOT GROUND to electrical conduit, or to a pipe carrying ANY gas or a flammable liquid such as oil or fuel.

Three-phase connection. Check phase requirement of equipment before installing. If only three-phase power is available, connect single-phase equipment to only two wires of the three-phase line. Do NOT connect the equipment ground lead to the third (live) wire, or the equipment will become electrically HOT - a dangerous condition that can shock, possibly fatally.

Before welding, check ground for continuity. Be sure conductors are touching bare metal of equipment frames at connections.

If a line cord with a ground lead is provided with the equipment for connection to a switch box, connect the ground lead to the grounded switch box. If a threeprong plug is added for connection to a grounded mating receptacle, the ground lead must be connected to the ground prong only. If the line cord comes with a three-prong plug, connect to a grounded mating receptacle. Never remove the ground prong from a plug, or use a plug with a broken ground prong.

2. Connectors

Fully insulated lock-type connectors should be used to join welding cable lengths.

3. Cables

Frequently inspect cables for wear, cracks, and damage. IMMEDIATELY

REPLACE those with excessively worn or damaged insulation to avoid possibly lethal shock from bared cable. Cables with damaged areas may be taped to give resistance equivalent to original cable.

Keep cable dry, free of oil and grease, and protected from hot metal and sparks.

4. Terminals and Other Exposed

Parts

Terminals and other exposed parts of electrical units should have insulating covers secured before operation.

5. Electrode Wire

Electrode wire becomes electrically HOT when the power switch of gas metal-arc welding equipment is ON and welding gun trigger is pressed. Keep hands and body clear of wire and other HOT parts.

6. Safety Devices

Safety devices such as interlocks and circuit breakers should not be disconnected or shunted out.

Before installation, inspection, or service of equipment, shut OFF all power, and remove line fuses (or lock or red-tag switches) to prevent accidental turning

ON of power. Disconnect all cables from welding power source, and pull all 115 volts line-cord plugs.

Do not open power circuit or change polarity while welding. If, in an emergency, it must be disconnected, guard against shock burns or flash from switch arcing.

Leaving equipment unattended. Always shut OFF, and disconnect all power to equipment.

Power disconnect switch must be available near the welding power source.

Cobra ®

MX Millermatic Compatible™ Owner's Manual - Page iii

Section A Installation

Technical Specifications

Wire Capacity

.030" - .045" (0.8mm - 1.2mm) solid hard wire, and cored wire

.030" - 1/16" (0.8mm - 1.6mm) aluminum

Wire Speed

800 IPM (20.3 mpm) max

Duty Cycle - 60%

All ratings are using Argon gas

175 Amps/25 Volts Air Cooled, 1/4" Tip (Model 280)

200 Amps/25 Volts Air Cooled, 3/8" Tip (Model 281)

225 Amps/25 Volts Water Cooled, 1/4" Tip (Model 282)

250 Amps/25 Volts Water Cooled, 3/8" Tip (Model 283)

Support Equipment Required

• C.V. or C.C. power source of sufficient capacity for your needs.

• Regulated gas supply and hoses.

• Properly sized power leads from power source to wire feeder and ground.

• Water source and hose capable of providing a minimum of

1 quart

(.95 liter) / min. at 45 p.s.i. when using water cooled guns.

Coolant Recommendations

Use Cobra Coolant (Aluminum Protection),which does not contain reactive sulphur or chlorine and does not react with copper, brass or aluminum. The

Cobra Coolant is available in quantities of 1 gallon (P/N 931-0060), 5 gallon

(P/N 931-0060-5GAL), or a case of 4 gallons each (P/N 931-0060-4).

The coolant flow rate should be a minimum of 10 GPH (1 qt/min) between

35 and 45psi. Contact the re-circulator manufacturer for specifications on pressure.

Gun Lead Connections

Power Cable - Air Cooled

A #2 power cable is used on the Cobra MX Millermatic Compatible gun. The gun and Power Pin ends of the cable are stripped to the copper strands and wrapped with a copper strip. A setscrew holds the cable securely in the gun body with torque requirements of 55-60 in-lb.

Power Cable - Water Cooled

The Cobra MX Millermatic Compatible water cooled gun utilizes a power/ water cable with a #6 AWG cable inside a 5/16” diameter hose.

The power cable ends are threaded fittings which screw into the gun body and the Power Manifold. These connections utilize a conductive sealant and are tightened with torque requirements of 100 + 5 IN-LB.

Conduit

The Cobra MX Millermatic Compatible comes standard with a poly-lined conduit, for feeding aluminum wire. The longer fitting with a shallow groove is used on the gun end. A set screw located on top of the gun handle secures the conduit in place. The cabinet end of the conduit is secured into the Power Pin connector with a set screw.

Gas Hose

The BLACK gas hose is pushed over a barbed fitting on the end of the gun body and secured by twisting the hose retainer to the end of the hose (shown next page). The opposite end of the BLACK hose is pushed over a barbed fitting in the Power Pin. The hose retainer is re-usable and can be removed and re-installed as needed.

Cobra

®

MX Millermatic Compatible™ Owner's Manual - Page 1

Section B

Coolant Connections

If so equipped, the ends of the coolant hose push over a barbed fitting on the end of the gun body and are secured by twisting the hose retainer to the end of the hose. The hose retainer is re-usable and can be removed and re-installed as needed.

The BLUE coolant supply hose pushes over a barbed fitting on the end of the gun body and is secured by twisting the hose retainer to the end of the hose. The hose retainer is re-usable and can be removed and re-installed as needed.The opposite end of the BLUE hose pushes into a threaded coolant fitting.

The RED coolant return hose pushes over the barbed fitting in the Power

Manifold. The opposite end of the RED hose pushes into a threaded return hose of the coolant recirculator.

Both threaded fittings on the end of the BLUE and RED hoses are standard left-hand thread. MK Products compatible guns have interchangeable fittings, so you can match as needed for your cooler. Both types of fittings require a hose retainer.

431-1898

5/16” Hose Retainer

431-1910

Quick Connect Fitting

431-1893*

Nipple

753-3379*

Left-Hand Threaded Fitting

*Must be ordered together

Control Cable

A multi-conductor control cable is used on the Cobra MX Millermatic

Compatible. The gun end of the cable is secured with a cable clamp and the wires are connected to the potentiometer, the micro switch, the motor and the gun body mechanically. Slack is left in the electric cable as it exits the back of the gun to prevent cable and/or wire breakage. The cabinet end of the control cable uses a 10-Pin, "X" clocked Amphenol connector.

Operation

General

The Cobra MX Millermatic Compatible gun maintains a constant, steady, uniform wire feed speed, regardless of curved or looped wire conduit. The constant push exerted by the slave motor in the cabinet, combined with the pull of the gun motor, causes the wire to literally float friction-free through the wire conduit. The 24VDC gun motor is controlled by a three and threequarter (3-3/4) turn potentiometer in the gun handle.

Controls and Settings

Potentiometer

The laterally-positioned potentiometer is located in the lower end of the handle, providing up to 800 ipm with

3-3/4 turns.

Micro Switch

The micro switch assembly consists of the micro switch, and leads.

Trigger Sensitivity

The amount of trigger lever travel can be shortened for a quicker or more responsive action.

Trigger Sensitivity

Adjustment Screw Location

A more sensitive trigger lever is produced by reducing the gap between the trigger lever and the micro switch lever. By turning-in the trigger sensitivity adjustment screw, it closed the gap between the trigger lever and the micro switch lever.

Screw adjusted out of trigger, pre-setting the micro-switch lever for shorter motion sensitivity.

Cobra

®


This will enable the operator to increase the sensitivity of the trigger lever.

Sensitivity Adjustment

With the wire feeder turned on (with or without welding wire loaded), turn the screw in until the micro-switch is activated. Once activated, the torch and wire feeder motors will begin feeding wire. Retract the screw accordingly until the system is deactivated and adjusted to the operators' liking.

Drive Roll and Idler Rolls

General

The Cobra MX Millermatic Compatible gun comes standard with a knurled drive roll and a grooved idler roll, which will handle both hard wire and aluminum wire with diameters of .030 to 1/16 inch and steel from .030 to

.045 inches. Optional insulated V-groove drive rolls are also available for aluminum wire if desired (see optional kits).

Drive roll tension is accomplished with a unique spring-loaded pressure screw. The Cobra MX Millermatic Compatible comes from the factory with the pressure adjustment screw preset.

NO ADJUSTMENT IS

REQUIRED FOR ALL SIzES AND TyPES OF WIRES

.

Drive Roll Installation/Removal

Note: Neither of the handles needs to be removed to access the drive or idler rolls.

Cam Lever

1. Pull the cam lever away from the idler roll. This will relieve the pressure against the drive roll (as shown in Figure 1).

Figure 1

2. Align the drive roll removal tool (P/N 931-

0100) over the flats of the drive roll (as shown in Figure 2). Hold the gun with one hand or on a table top, with the other hand give the removal tool a quick snap-turn in the

CLOCKWISE DIRECTION.

Figure 2

3. Once the drive roll is loose, continue to spin drive roll in the clockwise direction to remove the drive roll from the gun.

4. Install a new drive roll on the left-hand threaded shaft. The drive roll will self-tighten when it is feeding wire.

Idler Roll Installation and Removal

(Reference Figure 3)

1. Using a slot type screwdriver, loosen idler screw, taking care not to lose lock washer under idler roll.

2. Insert new idler roll and lock washer onto screw, insuring that idler groove is toward top and lock washer is beneath.

3. Tighten.

Figure 3

NOTE: Lock washer must be under idler roll or it will not turn freely.

Cobra

®


Section C Accessories

Optional Kits

Insulated Drive Roll Kits are used to prevent preheating of the aluminum wire which may soften it and clog the liner. This picking up of current at the drive rolls rather than at the contact tip is usually not a problem unless using too large of a contact tip or excessively oxidized aluminum wire.

Insulated Grooved Drive Roll Kit

.................................................. 005-0715

For

.030" (0.8mm) dia. aluminum wire. Includes insulated groove drive roll and insulated idler roll assy.


.................................................. 005-0716

For



.................................................. 005-0717

For


Insulated Grooved Drive Roll Kit....................................................005-0718

For 3/64" (1.2mm) dia. aluminum wire. Includes insulated groove drive roll and insulated idler roll assy.

Insulated Grooved Drive Roll Kit....................................................005-0719

For


Handle Kit

......................................................................................... 005-0725

Includes left and right handles, screws and drive roll door.

Trigger Kit..........................................................................................005-0726

Trigger kit includes a sensitivity adjustment screw replacement for all Cobra

MX Millermatic Compatible /CobraMAX guns.

Barrel Insulator Replacement Kit....................................................005-0696

Includes replacement barrel insulator and taper lock nut.

Conduits

Flat spiral steel conduit for steel & cored wire.

15 ft./4.5m ..................................................................................... 615-0621-15

25 ft./7.6m ..................................................................................... 615-0621-25

35 ft./10.7m ................................................................................... 615-0621-35

50 ft./15.2m ................................................................................... 615-0621-50

Optional nickel tube liner ................................................................ 431-2031

Snake Skins

Snake Skin protective covers are now standard on all guns. You may order spare replacement covers to protect the lead assy of the gun when the factory one becomes damaged or worn. It can easily be replaced in the field by means of Velcro © .

Snake Skin Cover 13ft (for 15ft leads) ...............................................931-0110

Snake Skin Cover 23ft (for 25ft leads) .............................................. 931-0122



Gas Valve Removal Tool

Gas valve removal is performed by using P/N 931-0105 Gas Valve Removal

Tool. This multifunctional tool has been slotted on one side to encompass and conform to the gas valve stem and seat into the slotted gas valve body as seen in Figures 1 and 2. Removal of the gas valve can be accomplished by turning the gas valve tool counter clockwise. Reinstall by turning clockwise. The tool doubles as a bottle opener.

Cobra

®


Gas Valve Removal Tool

Figure 1

Figure 2

Contact Tips

(Models 281 and 283)

Wire Size

Heavy Duty Contact Tip - 3/8" Diameter*

Tip ID Arc Tip Length

Part No.

.030” (0.8mm) .041” (1.0mm) Spray 1.57” (39.9mm) 621-0390-25

Short 1.82” (46.2mm) 621-0396-25

.035” (0.9mm) .044” (1.1mm) Spray

.035" (0.9mm) .044" (1.1mm)

.045" (1.1mm) .053" (1.35mm)

3/64” (1.2mm) .053” (1.35mm)

Short

Short

Spray

1.57” (39.9mm) 621-0391-25

621-0391-250 †

621-0391-500

††

1.82” (46.2mm) 621-0397-25

1.82” (46.2mm) 621-0398-25

1.57” (39.9mm)

621-0392-25

621-0392-250 †

3/64” (1.2mm) .060” (1.5mm) Spray

1/16” (1.6mm) .074” (1.9mm)

.085” (2.16mm)

*

Use of tip removal tool is recommended

**This size tip furnished with gun

Spray

Spray

621-0392-500 ††

1.57” (39.9mm) 621-0393-25**

621-0393-250

†

621-0393-500

††

1.57” (39.9mm) 621-0394-25

621-0395-25

† Also sold in quantities of 250

† † Also sold in quantities of 500

(Models 280 and 282)

1/4" Diameter Contact Tip*

Wire Size

Tip ID

.023” (0.6 mm) .031” (0.8 mm)

Arc

Spray

Tip Length

Part No.

1.50” (38.1 mm) 621-0057-25

.023” (0.6 mm) .031” (0.8 mm)

.030” (0.8 mm) .036” (0.9 mm)

.030” (0.8 mm) .037” (0.9 mm)

.035"/.030”

(0.9 mm /0.8 mm)

.041” (1.0 mm)

.035” (0.9 mm) .044” (1.1 mm)

Short

Spray

Short

Spray

Spray

1.75” (44.5 mm) 621-0328-25

1.50” (38.1 mm) 621-0325-25

1.75” (44.5 mm) 621-0326-25

1.50” (38.1 mm) 621-0076-25

.035” (0.9 mm) .041” (1.0 mm) Short

1.50” (38.1 mm) 621-0001-25

621-0001-250

†

621-0001-500

††

1.75” (44.5 mm) 621-0077-25

.035” (0.9 mm) .044” (1.1 mm) Short

3/64” (1.2 mm) .053” (1.35 mm) Spray

3/64” (1.2 mm) .060” (1.5 mm) Spray

1/16” (1.6 mm) .074” (1.9 mm)

1/16” (1.6 mm) .085”(2.1 mm)

Spray

Spray

1.75” (44.5 mm) 621-0002-25

1.50” (38.1 mm) 621-0327-25

1.50” (38.1 mm) 621-0003-25

**

621-0003-250

†

621-0003-500

††

1.50” (38.1 mm) 621-0075-25

1.50” (38.1 mm) 621-0153-25

**This size tip furnished with gun

* All tips sold in quantities of 25

† Also sold in quantities of 250

† † Also sold in quantities of 500

Cobra

®


(Models 281 and 283)

Spring Loaded Contact Tip - 3/8” Diameter

Wire Size

Tip ID Arc Tip Length

Qty Part Number

.030” (0.8 mm) .041” (1.0 mm) Spray 1.57” (39.9 mm) EA 621-0331

.035” (0.9 mm) .044” (1.1 mm) Spray 1.57” (39.9 mm) EA 621-0332

3/64” (1.2 mm)

1/16” (1.6 mm)

.060” (1.5 mm) Spray 1.57” (39.9 mm) EA 621-0334

.074” (1.9 mm) Spray 1.57” (39.9 mm) EA 621-0335

Section D

MAX Cups

(Models 281 and 283)

Cup I.D.

Part No.

#6, 3/8" (9.5mm) 621-0420

#8, 1/2" (12.7mm) 621-0421*

#10, 5/8" (15.9mm) 621-0422

Classic Cups

(Models 280 and 282

)

Cup I.D.

Part No.

#5, 1/4" (6.4mm) 621-0079

#6, 3/8" (9.5mm) 001-0137-4 †

#8, 1/2" (12.7mm) 001-0138-4* †

#10, 5/8" (15.8mm) 001-0139-4

†

*standard - furnished with gun

† sold in packs of 4 each

Part Number

931-0137

Tip Extenders and Gun Barrel Liners

Description

Teflon liner package, 5 pieces

615-0338 Steel wire only, .030 - .1/16" (0.8 - 0.9mm)

Tip Extender

621-0424

Cobra

®

MX Millermatic Compatible™ tip extender (Air cooled barrel only)

615-0250 Spiral steel liner for tip extender

Maintenance

Periodic Maintenance

Your Cobramatic system is designed to provide years of reliable service.

Maintenance of the gun will normally consist of a general cleaning of the wire guide system, including barrels, drive rolls, and conduits at regular intervals.

Remove spatter build-up from inside of nozzles with a hardwood stick.

The only parts on the Cobramatic system that are subject to normal wear are the conduit, contact tips, gas cups, front body liners, wire guides, drive and idler rolls. A supply of these parts should be maintained on hand.

The number of units in operation and the importance of minimal down time will determine to what extent spare parts should be stocked on hand. See the recommended spare parts list for the most commonly replaced parts.

If repairs do become necessary, qualified shop maintenance personnel can easily replace any part.

Maintenance Tools

Tool

Contact Tip Removal Tool

Part Number

931-0044

Drive Roll Removal Tool 931-0100

Cobra

®


Qty.

1

1

2

1

1

1

10

5

Recommended Spare Parts List

Part No.

Description

615-0620-15 Conduit - 15 ft

615-0620-25

615-0620-35

615-0620-50

005-0726

Conduit - 25 ft

Conduit - 35 ft

Conduit - 50 ft

Trigger Assy Kit

005-0725

511-0101

005-0686

Handle Kit

Drive Roll

Idler Roll Kit

DRIVE ROLL REMOVAL TOOL

931-0100

IDLER ROLL

005-0686

KNURLED DRIVE ROLL

511-0101

MICRO SWITCH ASSY KIT

003-2274

Cobra

®


Section E Troubleshooting

Trouble

No wire feed at gun, feeder not operating, i.e. no slave motor or brake solenoid.

No wire feed at gun, feeder operating properly.

Wire feeds, but welding wire is not energized.

Wire feeds erratically.

Wire feeds one speed only.

Wire walks out of drive rolls.

Cause

Input power fuse in feeder/control box blown

Remedy

Replace fuse.

Micro-switch defective/not being activated

Replace switch. Check switch for operation.

Broken electrical cable

Motor control fuse in feeder/control box blown

Bad potentiometer

Broken electrical cable.

Bad speed control/PCB.

Loose or no cable connections.

Check micro-switch wires for continuity.

Check motor leads for shorts; then replace fuse.

Check potentiometer with meter.

Check motor and potentiometer wires for continuity.

See specific cabinet/ control box owner's manual for speed control operation.

Check all power connections.

Contactor control cable loose or in wrong position

Welding power source

Dirty or worn conduit

Wrong size contact tip

Idler roll stuck

Check power supply owner's manual for location and type of contactor signal required, i.e. closing or 115VAC.

Check power source.

Blow out or replace conduit.

See contact tip table.

Check for lock washer under idler roll, or replace if damaged.

Bad potentiometer

Broken electrical cable

Bad speed control

Check with meter.

Check potentiometer wires for continuity or short.

See specific cabinet/ control owner's manual for speed control operation.

Idler roll upside-down

Place groove in idler roll toward top.

Rear wire guide missing Replace wire guide.

Cobra

®


Troubleshooting Guide

Regardless of which gun or feeder used, all MK Products’ push-pull guns operate on the same principle. The slave motor in the feeder runs at a fast,constant speed, but has very low torque. It is always trying to feed more wire than the gun motor wants, and when the motor gets all it wants, it slows the slave motor, preventing a bird’s nest. Because of the low torque produced by the slave motor, a brake system is used to prevent wire overrun rather than tension. The drag adjustment in the feeder is used simply to keep the wire slightly taut, so it will not pull off the spool while feeding wire.

The high torque 24VDC gun motor is controlled by a solid state speed control located in the feeder, and a pot located in the gun. The gun motor, potentiometer, and micro switch are connected to the cabinet/control box via a control cable and Amphenol connector. If this cable becomes damaged, a variety of symptoms can occur, depending on which wire(s) break. To test, check each wire for continuity and shorts.

Remember, the micro switch in the gun activates both the slave motor and gun motor circuits in the cabinet. Therefore, if the slave motor and brake solenoid operate, but the gun does not, look more toward the gun motor’s 24

V circuits, speed control, control cable, or the gun motor. If nothing operates, look more toward the slave motor’s input, micro switch leads, or micro switch.

Testing The Gun

Reference the "X" clocked Amphenol diagram on the Cobra MX Millermatic Compatible electrical diagram for information about pin-outs and locations.

Motor Check

Remove the connector from the cabinet.

Using the Amphenol connector, check the resistance across pins “A” and

“B”

(motor leads).

If an open circuit (more than K ohms) or short (less than 2 ohms) exists, check the motor leads and motor independently.

Testing the Gun Potentiometer

Using the amphenol connector, check the resistance across pin “F”

(wiper) and pin “E”. The resistance should vary from 0 - 5K ohms as the potentiometer is turned.

Check the resistance across pin “F” (wiper) and pin “H”. The resistance should vary from 5K - 0 ohms as the potentiometer is turned.

Testing the Micro Switch

Using the amphenol connector, check for continuity across pins “D” and “G” when the trigger is pressed.

Cobra

®


THIS pAgE INTENTIONALLY LEfT bLANK

Section F Appendices

Diagrams / Parts List

Exploded View .......................................................................... 12

Bill of Material ........................................................................... 13

Front Body Assembly ................................................................ 14

Rear Body Assembly, Air Cooled .............................................. 15

Rear Body Assembly, Water Cooled ......................................... 16

Classic Cup Barrel Assembly, Air Cooled ................................. 17

Classic Cup Barrel Assembly, Water Cooled ............................ 18

MAX Barrel Assembly, Air Cooled ............................................. 19

MAX Cup Barrel Assembly, Water Cooled ................................ 20

Lead Assembly, Air Cooled ....................................................... 21

Lead Assembly, Water Cooled .................................................. 22

Spiral Wrap Installation ............................................................. 23

Power Pin Adapter Assembly.................................................... 26

Power Manifold Assembly, Air Cooled ...................................... 27

Power Manifold Assembly, Water Cooled ................................. 28

Electrical ................................................................................... 29

Cobra

®


Cobra MX

Millermatic Compatible Head Assembly

Air Cooled

Water Cooled

Cobra

®


Cobra

®


Cobra MX Millermatic Compatible

Front Body Assembly

P/N 003-2141

Front Body Assembly

No.

Qty.

Part No.

Description

1 Not available separately

6

7

8

9

10

4

5

2

3

Not available separately

1 325-0206 Scr Ph 10-24-3/8

1 333-0082 Washer Lock 10

1 419-0092 Spring Comp 0.31 OD x 0.20 ID

1 421-0525 Pin Dowel 1/8 x 7/8 Sst

1 431-1663 Scr Adjust Idler

1 431-1598 Arm Idler Cobra

1 511-0001 Assy Idler Wire Feed

1 511-0101 Drive Roll Gold

Cobra

®


Cobra MX

Millermatic Compatible Rear Assembly

Air Cooled

P/N 003-2397

4

5

6

No.

Qty.

1 1

2

3

-

2

1

1

2

Air Cooled Rear Body Assembly

Part No.

Description

003-2199 Assy Gas Valve w/ Mod Valve

-

303-0096

321-1082

321-1104

411-0045


O-Ring .145 ID x .07 W

Set Screw Flat 1/4-20 5/16 SST

Set Screw Conduit

Tie Wrap

Cobra

®


Cobra

MX Millermatic Compatible Rear Assembly

Water Cooled

P/N 003-2398

4

5

2

3

No.

Qty.

Rear Body Assembly - Water Cooled

Part No.

Description

1 1 003-2199 Assy Gas Valve w/ Mod Valve

1

2

-

6

-

303-0096

321-1104

411-0045


O-Ring .145 ID x .07 W

Set Screw Conduit

Tie Wrap (not shown for clarity)

Cobra

®


Cobra

M

X Millermatic Compatible

Classic Cup

Barrel Assembly

Air Cooled, P/N 003-2341

*Apply silicone lubricant to item

3 before installing.

4

5

2

3*

6

Classic Cup Barrel Assembly - Air Cooled

No.

Qty.

Part No.

Description

1 1 001-0138 Assy Gas Cup MK #8

1

1

-

2

1

-

303-0096

437-0299

931-0137

621-0003


O-Ring .145 ID x .07W

Insulation Barrel

5-Piece Teflon Liner Package

Tip 0.06 x 0.25 OD

Cobra

®


Cobra

M

X

Millermatic

Compatible

Classic Cup

Barrel Assembly

Water Cooled, P/N 003-2342



4

5

2

3*

6

Classic Cup Barrel Assembly - Water Cooled

No.

Qty.

Part No.

Description

1 1 001-0138 Assy Gas Cup MK #8

1

1

-

6

1

-

303-0096

437-0299

931-0137

621-0003



Insulation Barrel


Tip 0.06 x 0.25 OD

Cobra

®


Cobra MX Lincoln Compatible MAX Cup

Barrel Assembly

Air Cooled, 003-2343



4

5

2*

3

6

MAX Cup Barrel Assembly - Air Cooled

No.

Qty.

Part No.

Description


1

1

6

1

1

303-0096

437-0299

931-0137

621-0393

621-0421


Insulation Barrel


Tip HD Spray .060

Assy Gas Cup #8 CobraMAX

Cobra

®


Cobra MX Lincoln Compatible MAX Cup

Barrel Assembly

Water Cooled, 003-2344



4

5

2*

3

6

MAX Cup Barrel Assembly - Water Cooled

No.

Qty.

Part No.

Description


1

1

6

1

1

303-0096

437-0299

931-0137

621-0393

621-0421


Insulation Barrel


Tip HD Spray .060

Assy Gas Cup #8 CobraMAX

Cobra

®


Cobra MX Millermatic Compatible Lead Assembly

Air Cooled

Lead Assembly - Air Cooled

No. Qty. Description

1 1 Assy Boot Torch

2 1 Assy Power Manifold, A/C

15' Part No. 25' Part No. 35' Part No. 50' Part No.

003-2153

003-2337

3 1 Assy Power Pin Adapter Miller 003-2338

6

7

4

5

1 Wrap Spiral Cord, 5.5 in

1 Wrap Spiral Cord, 13 in

1 Snake Skin

4 Screw SHC 4-40 x 1/2 SST

8 4 Tie Wrap .75 x Dia N Blk

9* 2 Hose Retainer, 5/16

10 1

11 1

Handle Kit: includes item number 7

931-0110

261-0094

261-0094-13

931-0122 931-0132

338-0014

411-0045

431-1898

005-0385-BLUE

931-0123

12 1 Assy Gas Hose

13 1 Conduit Tef Tube

14 -

15 -

----

----

552-0241-15 552-0241-25 552-0241-35 552-0241-50

615-0620-15 615-0620-25 615-0620-35 615-0620-50

----

----

16 1 Assy Controller Cable 005-0380-15 005-0380-25 005-0380-35 005-0380-50

1 Assy Power Cable Global 843-0640-15 843-0640-25 843-0640-35 843-0640-50

17**

1 Ultra Flex Power Cable (optional) 843-0715-15 843-0715-25 843-0715-35 843-0715-50

*

Hose Retainer is re-usable and can be removed and re-installed as needed

** power Cable includes copper wrap p/N 701-0053-1

Cobra

®


Cobra MX Millermatic Compatible Lead Assembly

Water Cooled

2

3

4

No. Qty. Description

1 1 Assy Boot Torch

Lead Assembly - Water Cooled

15' Part No. 25' Part No. 35' Part No. 50' Part No.

003-2153

1 Assy Power Pin Adapter Miller

1 Assy Power Manifold, W/C

1

Wrap Spiral Cord, 5.5 in

003-2338

003-2345

261-0094

5

6

7

8

1

1

4

4

Wrap Spiral Cord, 13 in

Snake Skin

Screw SHC 4-40 x 1/2 SST

Tie Wrap .75 x Dia N Blk

261-0094-13

931-0110 931-0122 931-0132 931-0123

338-0014

411-0045

431-1898 9* 4 Hose Retainer, 5/16

10 1

Handle Kit: includes item 7

11 1

12 1 Assy Hose Water RED Miller

13 1 Assy Hose Water, BLUE

14 1 Assy Gas Hose

005-0385-BLUE

552-0209

552-0239-15 552-0239-25 552-0239-35 552-0239-50

552-0241-15 552-0241-25 552-0241-35 552-0241-50

15 1 Conduit Tef Tube

16 ----

17 ----

18 1 Assy Controller Cable

615-0620-15 615-0620-25 615-0620-35 615-0620-50

----

----

005-0380-15 005-0380-25 005-0380-35 005-0380-50

19 1 Assy Power Cable/Water 005-0388-15 005-0388-25 005-0388-35 005-0388-50

*

Hose Retainer is re-usable and can be removed and re-installed as needed

Cobra

®



Lead Assembly Spiral Wrap Installation

033-0929

gun End, Air Cooled

Conduit

Spiral Wrap p/n: 261-0094-13

Power Cable

Cobra

®




033-0929

gun End, Water Cooled

Spiral Wrap p/n: 261-0094-13

Cobra

®




033-0929

Cabinet End, Air and Water Cooled

Spiral Wrap p/n: 261-0094

Cobra

®



Power Pin Adapter Assembly

P/N 003-2338

APPLY SILICONE LUBRICANT TO

O-RINGS BEFORE INSTALLING

No.

Qty.

1 1

2

3

2

2

Power Pin Adapter Assembly

Part No.

002-0726

303-0010

303-0102

Description

Assy Brazed Power Pin Adapter

O-Ring 2-014 .489 ID x .07 W

O-Ring .487 ID x .103 W

Cobra

®



Power Manifold Assembly, Push Fitting

Air Cooled, P/N 003-2337

2

3

3

No.

Qty.

Air Cooled

Power Manifold Assembly

Part No.

Description

1 1 321-1104 Set Screw Conduit

1

1

1

321-1082

431-1905

431-1936

Set Screw Flat 1/4 - 20 x 3/8 SST

Fitting 1/8 ID x 1/16 - 27 NPT

Power Manifold AC

Cobra

®



Power Manifold Assembly, Push Fitting

Water Cooled, P/N 003-2345

2

3

4

Water Cooled

Power Manifold Assembly

No.

Qty.

Part No.

Description

1 1 321-1104 Set Screw Conduit

2

1

1

431-1905

431-1951

751-0017

Fitting 1/8 ID x 1/16 - 27 NPT

Power Manifold WC

Plug Sealing 4MM x 4MM SST

Cobra

®


Cobra MX Millermatic Compatible Water Cooled

Electrical Schematic/Connector Pinout

Polarizing Key

"X" Clocked Connector

Viewed from back of connector

WARNING

ELECTRIC SHOCK

HAzARD

• Do not touch live electrical parts.

•

Disconnect input power or stop engine before servicing.

• Do not operate with covers removed.

• Have only qualified persons install, use, or service this units.

Cobra

®


Safety Warnings

Cobra

®


Cobra

®


16882 Armstrong Ave.

Irvine, CA 92606

Tel (949) 863-1234

Fax (949) 474-1428 www.mkproducts.com

August 1, 2010

THIS pAgE INTENTIONALLY bLANK

www.mkproducts.com

16882 Armstrong Ave.

Irvine, California 92606

TEL (949) 863-1234 FAX (949) 474-1428

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