Lincoln LN-742, LN-742H User Manual

IM476-A

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LN-742 & LN-742H Wire Feeders

For use with machines having Code Numbers:

Safety Depends on You

Lincoln arc welding and cutting equipment is designed and built with safety in mind. However, your overall safety can be increased by proper installation ... and thoughtful operation on your part. DO

NOT INSTALL, OPERATE OR REPAIR THIS EQUIPMENT WITHOUT READING THIS MANUAL AND THE SAFETY PRECAUTIONS CONTAINED THROUGHOUT. And, most

importantly, think before you act and be careful.

August, 2005

10027 10028 10048 10049 10238 10239 10240 10241

OPERATOR’S MANUAL

• World's Leader in Welding and Cutting Products •

• Sales and Service through Subsidiaries and Distributors Worldwide •

Cleveland, Ohio 44117-1199 U.S.A. TEL: 216.481.8100 FAX: 216.486.1751 WEB SITE: www.lincolnelectric.com

SAFETY

WARNING

CALIFORNIA PROPOSITION 65 WARNINGS

Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.

The Above For Diesel Engines

ARC WELDING CAN BE HAZARDOUS. PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH. KEEP CHILDREN AWAY. PACEMAKER WEARERS SHOULD CONSULT WITH THEIR DOCTOR BEFORE OPERATING.

Read and understand the following safety highlights. For additional safety information, it is strongly recommended that you purchase a copy of “Safety in Welding & Cutting - ANSI Standard Z49.1” from the American Welding Society, P.O. Box 351040, Miami, Florida 33135 or CSA Standard W117.2-1974. A Free copy of “Arc Welding Safety” booklet E205 is available from the Lincoln Electric Company, 22801 St. Clair Avenue, Cleveland, Ohio 44117-1199.

BE SURE THAT ALL INSTALLATION, OPERATION, MAINTENANCE AND REPAIR PROCEDURES ARE PERFORMED ONLY BY QUALIFIED INDIVIDUALS.

The engine exhaust from this product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.

The Above For Gasoline Engines

FOR ENGINE powered equipment.

1.a. Turn the engine off before troubleshooting and maintenance work unless the maintenance work requires it to be running.

____________________________________________________

1.b.Operate engines in open, well-ventilated areas or vent the engine exhaust fumes outdoors.

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1.c. Do not add the fuel near an open flame

welding arc or when the engine is running. Stop the engine and allow it to cool before refueling to prevent spilled fuel from vaporizing on contact with hot engine parts and igniting. Do not spill fuel when filling tank. If fuel is spilled, wipe it up and do not start engine until fumes have been eliminated.

____________________________________________________

1.d. Keep all equipment safety guards, covers

and devices in position and in good repair.Keep hands, hair, clothing and tools away from V-belts, gears, fans and all other moving parts when starting, operating or repairing equipment.

____________________________________________________

1.e. In some cases it may be necessary to remove safety guards to perform required maintenance. Remove guards only when necessary and replace them when the maintenance requiring their removal is complete. Always use the greatest care when working near moving parts.

___________________________________________________

1.f. Do not put your hands near the engine fan. Do not attempt to override the governor or idler by pushing on the throttle control rods while the engine is running.

___________________________________________________

1.g. To prevent accidentally starting gasoline engines while turning the engine or welding generator during maintenance work, disconnect the spark plug wires, distributor cap or magneto wire as appropriate.

1.h. To avoid scalding, do not remove the radiator pressure cap when the engine is hot.

ELECTRIC AND MAGNETIC FIELDS may be dangerous

2.a. Electric current flowing through any conductor causes localized Electric and Magnetic Fields (EMF). Welding current creates EMF fields around welding cables and welding machines

2.b. EMF fields may interfere with some pacemakers, and welders having a pacemaker should consult their physician before welding.

2.c. Exposure to EMF fields in welding may have other health effects which are now not known.

2.d. All welders should use the following procedures in order to minimize exposure to EMF fields from the welding circuit:

2.d.1.

Route the electrode and work cables together - Secure them with tape when possible.

2.d.2. Never coil the electrode lead around your body.

2.d.3. Do not place your body between the electrode and

work cables. If the electrode cable is on your right side, the work cable should also be on your right side.

2.d.4. Connect the work cable to the workpiece as close as

possible to the area being welded.

2.d.5. Do not work next to welding power source.

Mar ‘95

SAFETY

ELECTRIC SHOCK can kill.

3.a. The electrode and work (or ground) circuits are electrically “hot” when the welder is on. Do not touch these “hot” parts with your bare skin or wet clothing. Wear dry, hole-free

gloves to insulate hands.

3.b. Insulate yourself from work and ground using dry insulation. Make certain the insulation is large enough to cover your full area of physical contact with work and ground.

In addition to the normal safety precautions, if welding must be performed under electrically hazardous conditions (in damp locations or while wearing wet clothing; on metal structures such as floors, gratings or scaffolds; when in cramped positions such as sitting, kneeling or lying, if there is a high risk of unavoidable or accidental contact with the workpiece or ground) use the following equipment:

• Semiautomatic DC Constant Voltage (Wire) Welder.

• DC Manual (Stick) Welder.

• AC Welder with Reduced Voltage Control.

3.c. In semiautomatic or automatic wire welding, the electrode, electrode reel, welding head, nozzle or semiautomatic welding gun are also electrically “hot”.

3.d. Always be sure the work cable makes a good electrical connection with the metal being welded. The connection should be as close as possible to the area being welded.

3.e. Ground the work or metal to be welded to a good electrical (earth) ground.

ARC RAYS can burn.

4.a. Use a shield with the proper filter and cover plates to protect your eyes from sparks and the rays of the arc when welding or observing open arc welding. Headshield and filter lens should conform to ANSI Z87. I standards.

4.b. Use suitable clothing made from durable flame-resistant material to protect your skin and that of your helpers from the arc rays.

4.c. Protect other nearby personnel with suitable, non-flammable screening and/or warn them not to watch the arc nor expose themselves to the arc rays or to hot spatter or metal.

FUMES AND GASES can be dangerous.

5.a. Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases.When welding, keep your head out of the fume. Use enough ventilation and/or exhaust at the arc to keep

fumes and gases away from the breathing zone. When

welding with electrodes which require special ventilation such as stainless or hard facing (see instructions on container or MSDS) or on lead or cadmium plated steel and other metals or coatings which produce highly toxic fumes, keep exposure as low as possible and below Threshold Limit Values (TLV) using local exhaust or mechanical ventilation. In confined spaces or in some circumstances, outdoors, a respirator may be required. Additional precautions are also required when welding on galvanized steel.

3.f.

Maintain the electrode holder, work clamp, welding cable and welding machine in good, safe operating condition. Replace damaged insulation.

3.g. Never dip the electrode in water for cooling.

3.h. Never simultaneously touch electrically “hot” parts of electrode holders connected to two welders because voltage between the two can be the total of the open circuit voltage of both welders.

3.i. When working above floor level, use a safety belt to protect yourself from a fall should you get a shock.

3.j. Also see Items 6.c. and 8.

5.b.

Do not weld in locations near chlorinated hydrocarbon

coming from degreasing, cleaning or spraying operations. The heat and rays of the arc can react with solvent vapors form phosgene, a highly toxic gas, and other irritating products.

5.c. Shielding gases used for arc welding can displace air and

cause injury or death. Always use enough ventilation, especially in confined areas, to insure breathing air is safe.

5.d. Read and understand the manufacturer’s instructions for this

equipment and the consumables to be used, including the

material safety data sheet (MSDS) and follow your

employer’s safety practices. MSDS forms are available from

your welding distributor or from the manufacturer.

5.e. Also see item 1.b.

Mar ‘95

vapors

iii

SAFETY

iii

WELDING SPARKS can cause fire or explosion.

6.a.

Remove fire hazards from the welding area.

If this is not possible, cover them to prevent

the welding sparks from starting a fire.

materials from welding can easily go through small cracks and openings to adjacent areas. Avoid welding near hydraulic lines. Have a fire extinguisher readily available.

6.b. Where compressed gases are to be used at the job site, special precautions should be used to prevent hazardous situations. Refer to “Safety in Welding and Cutting” (ANSI Standard Z49.1) and the operating information for the equipment being used.

6.c. When not welding, make certain no part of the electrode circuit is touching the work or ground. Accidental contact can cause overheating and create a fire hazard.

6.d. Do not heat, cut or weld tanks, drums or containers until the proper steps have been taken to insure that such procedures will not cause flammable or toxic vapors from substances inside. They can cause an explosion even been “cleaned”. For information, purchase “Recommended Safe Practices for the Containers and Piping That Have Held Hazardous Substances”, AWS F4.1 from the American Welding Society

(see address above).

6.e. Vent hollow castings or containers before heating, cutting or welding. They may explode.

Sparks and spatter are thrown from the welding arc. Wear oil

6.f. free protective garments such as leather gloves, heavy shirt, cuffless trousers, high shoes and a cap over your hair. Wear ear plugs when welding out of position or in confined places. Always wear safety glasses with side shields when in a welding area.

6.g. Connect the work cable to the work as close to the welding area as practical. Work cables connected to the building framework or other locations away from the welding area increase the possibility of the welding current passing through lifting chains, crane cables or other alternate circuits. This can create fire hazards or overheat lifting chains or cables until they fail.

6.h. Also see item 1.c.

Remember that welding sparks and hot

though

they have

Preparation

for Welding and Cutting of

CYLINDER may explode if damaged.

7.a. Use only compressed gas cylinders containing the correct shielding gas for the process used and properly operating regulators designed for the gas and

pressure used. All hoses, fittings, etc. should be suitable for the application and maintained in good condition.

7.b. Always keep cylinders in an upright position securely chained to an undercarriage or fixed support.

7.c. Cylinders should be located:

• Away from areas where they may be struck or subjected to

physical damage.

• A safe distance from arc welding or cutting operations and

any other source of heat, sparks, or flame.

7.d. Never allow the electrode, electrode holder or any other electrically “hot” parts to touch a cylinder.

7.e. Keep your head and face away from the cylinder valve outlet when opening the cylinder valve.

7.f. Valve protection caps should always be in place and hand tight except when the cylinder is in use or connected for use.

7.g. Read and follow the instructions on compressed gas cylinders, associated equipment, and CGA publication P-l, “Precautions for Safe Handling of Compressed Gases in Cylinders,” available from the Compressed Gas Association 1235 Jefferson Davis Highway, Arlington, VA 22202.

FOR ELECTRICALLY powered equipment.

8.a. Turn off input power using the disconnect switch at the fuse box before working on the equipment.

8.b. Install equipment in accordance with the U.S. National Electrical Code, all local codes and the manufacturer’s recommendations.

8.c. Ground the equipment in accordance with the U.S. National Electrical Code and the manufacturer’s recommendations.

Mar ‘95

SAFETY

PRÉCAUTIONS DE SÛRETÉ

Pour votre propre protection lire et observer toutes les instructions et les précautions de sûreté specifiques qui parraissent dans ce manuel aussi bien que les précautions de sûreté générales suivantes:

Sûreté Pour Soudage A L’Arc

1. Protegez-vous contre la secousse électrique:

a. Les circuits à l’électrode et à la piéce sont sous tension

quand la machine à souder est en marche. Eviter toujours tout contact entre les parties sous tension et la peau nue ou les vétements mouillés. Porter des gants secs et sans trous pour isoler les mains.

b. Faire trés attention de bien s’isoler de la masse quand on

soude dans des endroits humides, ou sur un plancher metallique ou des grilles metalliques, principalement dans les positions assis ou couché pour lesquelles une grande partie du corps peut être en contact avec la masse.

c. Maintenir le porte-électrode, la pince de masse, le câble

de soudage et la machine à souder en bon et sûr état defonctionnement.

d.Ne jamais plonger le porte-électrode dans l’eau pour le

refroidir.

e. Ne jamais toucher simultanément les parties sous tension

des porte-électrodes connectés à deux machines à souder parce que la tension entre les deux pinces peut être le total de la tension à vide des deux machines.

f. Si on utilise la machine à souder comme une source de

courant pour soudage semi-automatique, ces precautions pour le porte-électrode s’applicuent aussi au pistolet de soudage.

2. Dans le cas de travail au dessus du niveau du sol, se protéger contre les chutes dans le cas ou on recoit un choc. Ne jamais enrouler le câble-électrode autour de n’importe quelle partie du corps.

5. Toujours porter des lunettes de sécurité dans la zone de soudage. Utiliser des lunettes avec écrans lateraux dans les zones où l’on pique le laitier.

6. Eloigner les matériaux inflammables ou les recouvrir afin de prévenir tout risque d’incendie dû aux étincelles.

7. Quand on ne soude pas, poser la pince à une endroit isolé de la masse. Un court-circuit accidental peut provoquer un échauffement et un risque d’incendie.

8. S’assurer que la masse est connectée le plus prés possible de la zone de travail qu’il est pratique de le faire. Si on place la masse sur la charpente de la construction ou d’autres endroits éloignés de la zone de travail, on augmente le risque de voir passer le courant de soudage par les chaines de levage, câbles de grue, ou autres circuits. Cela peut provoquer des risques d’incendie ou d’echauffement des chaines et des câbles jusqu’à ce qu’ils se rompent.

9. Assurer une ventilation suffisante dans la zone de soudage. Ceci est particuliérement important pour le soudage de tôles galvanisées plombées, ou cadmiées ou tout autre métal qui produit des fumeés toxiques.

10. Ne pas souder en présence de vapeurs de chlore provenant d’opérations de dégraissage, nettoyage ou pistolage. La chaleur ou les rayons de l’arc peuvent réagir avec les vapeurs du solvant pour produire du phosgéne (gas fortement toxique) ou autres produits irritants.

11. Pour obtenir de plus amples renseignements sur la sûreté, voir le code “Code for safety in welding and cutting” CSA Standard W 117.2-1974.

PRÉCAUTIONS DE SÛRETÉ POUR

3. Un coup d’arc peut être plus sévère qu’un coup de soliel, donc:

a. Utiliser un bon masque avec un verre filtrant approprié

ainsi qu’un verre blanc afin de se protéger les yeux du rayonnement de l’arc et des projections quand on soude ou quand on regarde l’arc.

b. Porter des vêtements convenables afin de protéger la

peau de soudeur et des aides contre le rayonnement de l‘arc.

c. Protéger l’autre personnel travaillant à proximité au

soudage à l’aide d’écrans appropriés et non-inflammables.

4. Des gouttes de laitier en fusion sont émises de l’arc de soudage. Se protéger avec des vêtements de protection libres de l’huile, tels que les gants en cuir, chemise épaisse, pantalons sans revers, et chaussures montantes.

LES MACHINES À SOUDER À TRANSFORMATEUR ET À REDRESSEUR

1. Relier à la terre le chassis du poste conformement au code de l’électricité et aux recommendations du fabricant. Le dispositif de montage ou la piece à souder doit être branché à une bonne mise à la terre.

2. Autant que possible, I’installation et l’entretien du poste seront effectués par un électricien qualifié.

3. Avant de faires des travaux à l’interieur de poste, la debrancher à l’interrupteur à la boite de fusibles.

4. Garder tous les couvercles et dispositifs de sûreté à leur place.

Mar. ‘93

for selecting a QUALITY product by Lincoln Electric. We want you

Thank You

to take pride in operating this Lincoln Electric Company product

••• as much pride as we have in bringing this product to you!

Please Examine Carton and Equipment For Damage Immediately

When this equipment is shipped, title passes to the purchaser upon receipt by the carrier. Consequently, Claims for material damaged in shipment must be made by the purchaser against the transportation company at the time the shipment is received.

Please record your equipment identification information below for future reference. This information can be found on your machine nameplate.

Product _________________________________________________________________________________

Model Number ___________________________________________________________________________

Code Number or Date Code_________________________________________________________________

Serial Number____________________________________________________________________________

Date Purchased___________________________________________________________________________

Where Purchased_________________________________________________________________________

Whenever you request replacement parts or information on this equipment, always supply the information you have recorded above. The code number is especially important when identifying the correct replacement parts.

On-Line Product Registration

- Register your machine with Lincoln Electric either via fax or over the Internet.

• For faxing: Complete the form on the back of the warranty statement included in the literature packet accompanying this machine and fax the form per the instructions printed on it.

• For On-Line Registration: Go to our

“Product Registration”. Please complete the form and submit your registration.

Read this Operators Manual completely before attempting to use this equipment. Save this manual and keep it handy for quick reference. Pay particular attention to the safety instructions we have provided for your protection. The level of seriousness to be applied to each is explained below:

WEB SITE at www.lincolnelectric.com. Choose “Quick Links” and then

WARNING

This statement appears where the information must be followed exactly to avoid serious personal injury or loss of life.

CAUTION

This statement appears where the information must be followed to avoid minor personal injury or damage to this equipment.

TABLE OF CONTENTS

Page

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i-iv

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

Technical Specifications - LN-742 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Mounting Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Input Cable Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Work Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Gun and Cable Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Gun Cable Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Water Connections (For Water Cooled Guns) . . . . . . . . . . . . . . . . . . . . . A-6

GMAW Shielding Gas Hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-7

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

Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Recommended Processes and Equipment . . . . . . . . . . . . . . . . . . . . . . . B-1

Controls and Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

Acceleration Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

English or Metric Speed Display Units . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

Circuit Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

Drive Roll Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

Idle Roll Pressure Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-7

Wire Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-8

Making a Weld . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-12

Wire Reel Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-12

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

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

Flux System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

Power Input Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

Welding Guns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

Spindles, Stands, and Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

Attaching the Wire Reel Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-5

Drive Roll Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-6

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

Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

Periodic Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

Troubleshooting and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section E

How To Use Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1

Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2

Electrical Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section F

Parts Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-228

LN-742 & LN-742H

A-1

INSTALLATION

TECHNICAL SPECIFICATIONS – LN-742

INPUT VOLTAGE

40 to 42V ±10%, 50/60 Hz, 4.0 Amps

WIRE FEED SPEED

A-1

SYSTEM

LN-742

LN-742H

SYSTEM

LN-742

LN-742H

LN-742

LN-742H

OPERATING

STORAGE

BOTH LN-742 AND LN-742H

2 ROLL FEEDER WITHOUT WIRE STAND

WIRE SPEED RANGE

50 in. to 770 in. per minute (1.25 to 19.5 m/min)

80 in. to 1200 in. per minute (2.00 to 30.5 m/min)

WIRE DIAMETERS

ELECTRODE

SOLID

CORED

0.025 in. through 1/16 in. (0.6 through 1.6 mm)

0.025 in. through 0.045 in. (0.6 through 1.2 mm)

0.045 in. through 3/32 in. (1.2 through 2.4 mm)

DIAMETER

0.035 in. (0.9 mm)

TEMPERATURE RATING (ALL MODELS)

-4˚F to 104˚F (-20˚C to +40˚C)

-40˚F to 104˚F (-40˚C to +40˚C)

PHYSICAL DIMENSIONS

LENGTH

9.62 in.

(244 mm)

WIDTH

9.76 in.

(247 mm)

HEIGHT

10.89 in.

(277 mm)

TOTAL WEIGHT

LESS ELECTRODE

24 lbs

(11.0 kg)

2 ROLL FEEDER WITH WIRE STAND (K377)

4 ROLL FEEDER WITHOUT WIRE STAND

4 ROLL FEEDER WITH WIRE STAND (K377)

ENVIRONMENTAL RATING (ALL MODELS)

20.68 in.

(525 mm)

10.60 in.

(269 mm)

21.66 in.

(550 mm)

IP21 (IEC 529)

LN-742 & LN-742H

9.76 in.

(247 mm)

11.60 in.

(295 mm)

11.60 in.

(295 mm)

17.00 in.

(432 mm)

11.11 in.

(282 mm)

17.00 in.

(432 mm)

34 lbs

(15.5 kg)

28.7 lbs

(13.1 kg)

38.7 lbs

(17.7 kg)

A-2

NUT

STUD

ELECTRODE

CONTROL

CABLE

COPPER

STRAP

MOUNTING LOCATION

INSTALLATION

A-2

The LN-742 wire feeders can be mounted directly on top of the power source providing that it is secure and level. The LN-742 can also be mounted to an undercarriage when portability is required. The LN-742 should be installed upright on a horizontal surface.

A K178-1 mounting platform is available for mounting the LN-742 to the top of Idealarc power sources. Refer to Section C, Accessories, for details.

INPUT CABLE CONNECTIONS

Refer to Section C, Accessories, for descriptions of the various input cable assemblies available for the LN-742 wire feeder.

WARNING

Turn input power off before connecting the LN-742 wire feeder.

------------------------------------------------------------------------

For connecting an LN-742 to a specific Lincoln power source, follow steps 1 through 5, and refer to the connection diagram in Figure A.3. The welding cable used must be sized according to the current and the duty cycle of the application.

1. Connect the end of the control cable with the 14pin cable plug to the mating receptacle on the power source.

2. Connect the electrode lead to the power source output terminal of the desired polarity.

3. Referring to Figure A.1, route the other end of the electrode cable through the large oval hole in the rear panel of the LN-742 case. Connect the electrode to the copper strap on the side of the gearbox using the stud and nut provided.

FIGURE A.1 – INPUT CONTROL CABLE AND

ELECTRODE CABLE CONNECTIONS.

With input power disconnected at the source, install the input cable per connection diagram A.3, and complete the following instructions:

LN-742 & LN-742H

A-3

WIRE REEL MOUNTING ASSEMBLY

CONTROL

CABLE

ELECTRODE

CABLE

STRAIN RELIEF CLAMP

INSTALLATION

A-3

4. Connect the remaining end of the control cable with the eight-socket cable plug to the mating receptacle on the LN-742.

5. Referring to Figure A.2, install the input cable under the wire reel mounting stand strain relief clamp. Remove the screws holding the clamp to the base of wire reel mounting assembly. Put the input cable under the clamp and reinstall the screws.

The connection diagram, Figure A.3, shows the electrode as positive. To change polarity, turn the power source off. Reverse the electrode and work cables at the power source, and set the wire feeder voltmeter polarity switch on the power source to the proper polarity.

Pins not listed in the table in Figure A.3 are not connected on the cable.

If using the K589-1 remote control kit, set the power source control switch to the “Remote” position.

FIGURE A.2 – STRAIN RELIEF CLAMP.

LN-742 & LN-742H

A-4

ELECTRIC

SHOCK

CAN KILL

TURN INPUT POWER OFF BEFORE CONNECTING THE LN-742 WIRE FEEDER.

WARNING

CLEVELAND, OHIO U.S.A

LINCOLN

POWER SOURCE

LN-742

WIRE FEEDER

LN-742

INPUT CABLE

ASSEMBLY

TO WORK

ELECTRODE CABLE

14-SOCKET BOX RECEPTACLE, FRONT VIEW AND 14-PIN CABLE PLUG, REAR VIEW

FUNCTIONS ARE LISTED FOR REFERENCE ONLY AND EACH MAY OR MAY NOT BE PRESENT IN YOUR EQUIPMENT.

14-SOCKET BOX RECEPTACLE, REAR VIEW AND 14-PIN CABLE PLUG, FRONT VIEW

14 PIN

AMPHENOL

K=42

I=41 I=41

H=21 H=21C=2 C=2

G=75 G=75D=4 D=4

F=76

2 TRIGGER CIRCUIT

TRIGGER CIRCUIT

OUTPUT CONTROL

WORK

42V AC

LEAD FUNCTION

F=76E=77 E=77

INSTALLATION

FIGURE A.3 – LN-742 WIRE FEEDER TO LINCOLN POWER SOURCE – CONNECTION DIAGRAM.

A-4

LN-742 & LN-742H

A-5

AMPHENOL

PLUG

GUN CABLE

ASSEMBLY

CONDUCTOR

BLOCK

LOCKING

KNOB

INSTALLATION

A-5

WORK CABLE

Connect a work lead of sufficient size and length (Table A.1) between the proper output stud on the power source and the work. Be sure the connection to the work makes tight metal-to-metal electrical contact.

TABLE A.1 – WORK LEAD SPECIFICATIONS

Copper Work Cable Size, AWG

Current 60% Up To 50 Ft 50 Ft-100 Ft

Duty Cycle (15.2 m 300 Amps 0 (53 mm

400 Amps 00 (67 mm 500 Amps 00 (67 mm2) 000 (85 mm2) 600 Amps 000 (85 mm2) 0000 (107 mm2)

) (15.2-30.4 m2)

) 00 (67 mm2)

) 000 (85 mm2)

GUN AND CABLE ASSEMBLIES

The LN-742 can be used with several guns. In most cases, Lincoln guns and cables are shipped assembled, ready to weld. Use the gun and cable assembly for the electrode type (solid, Outershield , or Innershield) and electrode size to be used. Refer to Section C, Accessories, for different gun types.

Connect the control cable amphenol plug into the mating 5-cavity receptacle on the front of the control section below the keypad.

FIGURE A.4 – GUN CABLE CONNECTIONS.

GUN CABLE CONNECTIONS

Lay the cable out straight. Insert the connector on the welding conductor cable through the large hole in the front panel of the LN-742 and into the brass conductor block on the front of the gearbox. Refer to Figure A.4. Make sure it is all the way in and tighten the locking knob. Keep this connection clean and bright.

LN-742 & LN-742H

A-6

INSTALLATION

A-6

WATER CONNECTIONS (FOR WATER COOLED GUNS)

The LN-742 must have a K590-1 Water Solenoid Kit installed (see Section C, Accessories). Refer to Figure A.5 and perform the following steps:

The maximum water pressure permitted for use with the LN-742 is 55 psi (3.8 bar).

NOTE: If not using a Lincoln water cooler, and if your water cooling device is not designed for use with a waterline solenoid valve, you may remove the solenoid and screw the male fitting (after applying sealant) directly into the brass manifold block.

FIGURE A.5 – WATER CONNECTIONS.

1. Using male 5/8-18 UNF left-hand thread fittings, connect appropriate water hoses to the coolant inlet and outlet on the back of the LN-742. Connect the other ends of these hoses to the appropriate ports on your water cooling units.

2. In the event the water line fittings on your water cooled gun are incompatible with the female quick connects on the front of the LN-742, male quick connects are provided for installation on 3/16 in. I.D. hose (customer to provide appropriate clamps). The feeder connectors self seal when disconnected.

LN-742 & LN-742H

A-7

GAS

SUPPLY

HOSE

GAS

INERT

GAS

FITTING

INSTALLATION

A-7

GMAW SHIELDING GAS HOOKUP

WARNING

Gas under pressure is explosive. Always keep gas cylinders in an upright position and chained to the undercarriage or a stationary support. See American National Standard Z-49.1, “Safety In Welding And Cutting”, published by the American Welding Society.

------------------------------------------------------------------------

Customer must provide a cylinder of shielding gas, a pressure regulator, a flow control valve, and a hose from the flow valve to the gas inlet fitting of the LN-742. Install per Figure A.6 and the following:

1. Connect the supply hose from the gas cylinder flow valve outlet to the 5/8-18 female inert gas fitting on the back panel of the LN-742.

2. Install the barbed fitting and union nut to the 5/8-18 female inert gas fitting on the front of the LN-742. Connect 3/16 in. (4.8 mm) I.D. gas hose from the gun to the barbed fitting.

When the gun is to be removed, this fitting can be easily detached by loosening the union nut.

The LN-742 can be used with any shielding gas recommended in the electrode’s product literature at a maximum pressure of 60 psi (4.1 bar). This may include gasses such as Argon, Helium and Nitrogen and blended gases such as Ar-He, Ar-N2, Ar-O2,Ar-

CO2, CO2, AR-CO2,-O2.

FIGURE A.6 – SHIELDING GAS HOOKUP.

LN-742 & LN-742H

B-1

OPERATION

B-1

OPERATING INSTRUCTIONS

Read and understand the entire Operation Section prior to operating the machine.

SAFETY PRECAUTIONS

WARNING

ELECTRIC SHOCK can kill.

• Do not touch electrically live parts or electrode with skin or wet clothing.

• Insulate yourself from work or ground.

• Always wear dry insulating gloves.

GENERAL DESCRIPTION

The K617 LN-742 semiautomatic constant speed wire feeder is specifically equipped for gas metal arc welding using flux-cored Outershield electrodes and solid wire. The LN-742 is also suitable for self-shielded flux-cored Innershield electrodes, submerged arc welding (if constant voltage is satisfactory), and other open arc welding. It has been factory assembled with the following features:

• Wire feed control [50 to 770 in./min (1.25 to 19.5 m/min) for the LN-742; 80 to 1200 in./min (2.00 to

30.5 m/min) for the LN-742H].

• Factory installed gas solenoid valve and gas fittings.

• Wire drive uses a permanent magnet motor and includes tool-less “quick-release” idle roll pressure arm, outgoing guide tube and gun cable fastening.

• Optional factory installed water solenoid and fittings for use with water cooled welding guns.

FUMES AND GASES can be dangerous.

• Keep your head out of fumes.

• Use ventilation or exhaust to

remove fumes from breathing zone.

WELDING SPARKS can cause fire or explosion.

• Keep flammable material away.

• Do not weld on containers that

have held combustibles.

ARC RAYS can burn.

• Wear eye, ear, and body protection.

Observe additional Safety Guidelines detailed in the beginning of this manual.

The LN-742 4-Roll is designed to provide the additional feeding force required when using gun cables over 15 ft (4.6 m) long or when the wire is pulled long distances (such as when bulk packages are used). Because the four-roll feeder has twice the contact surface, it can also help when feeding softer wires by delivering the same or more feeding force as the two-roll with less overall wire deformation.

RECOMMENDED PROCESSES AND EQUIPMENT

The LN-742 is recommended for use in MIG and Innershield welding applications with constant voltage power sources with 42 VAC auxiliary power and a 14pin connector receptacle, such as the Invertec V300PRO, V350-PRO, DC-400, DC-600, DC-655 DC-650PRO, or Lincoln CV type power sources.

The LN-742 is capable of the following wire feed ranges:

• 0.025 to 1/16 in. (0.6 to 1.6 mm) solid wire for gasmetal-arc or CV submerged arc processes.

• 0.045 to 3/32 in. (1.2 to 2.4 mm) cored wire for Outershield gas-metal-arc processes.

LN-742 & LN-742H

B-2

COLD INCH

OLTMETER

INCH

WFS

PREFLOW POSTFLOW

BURNBACK

SPOT

STD

LOCK

SPOT

TIMETRIGGER MODE

GAS PURGE

GAS

PURGE

KEY

LED

DISPLAY

FUNCTION SELECTION CONTROLS

TIMER SELECTION CONTROLS

SETTING

ADJUSTMENT

ARROW KEYS

TRIGGER

MODE

CONTROLS

COLD

INCH

KEY

OPERATION

B-2

• 0.045 to 5/64 in. (1.2 to 2.0 mm) cored wire for Innershield processes.

The LN-742H is capable of the following wire feed ranges:

• 0.025 to 0.045 in. (0.6 to 1.2 mm) solid wire for gasmetal-arc or CV submerged arc processes.

• 0.035 to 0.045 in. (1.2 mm) cored wire for Outershield, Metalshield or Innershield processes.

CONTROLS AND SETTINGS

The operator controls are located on the keypad shown in Figure B.1. The keypad consists of: 7 membrane keys with tactile-feel embossed domes, that are generously spaced to provide easy selection, even while wearing welding gloves; a long-life, 3-1/2 digit, 7 segment LED display with 0.56 in. (14.2 mm) character height, permitting easy viewing even from long gun cable distances; and high intensity, red, LED indicator lights that allow for viewing at almost any angle.

TRIGGER MODE CONTROLS. This control enables the operator to choose the mode of operation as shown by the indicator lights. Pressing the key causes the mode lights to sequence (from top to bottom).

FIGURE B.1 – WIRE FEEDER CONTROLS.

The top light indicates standard (two-step) trigger mode. In this mode the unit will only be active when the trigger is pressed. The middle light indicates lock (four-step) trigger mode. In this mode the solenoid is energized when the trigger is pressed, the power source and wire feeder are energized after preflow time when the trigger is released. Closing the trigger a second time turns off the wire feeder and then the power source after burnback time. Releasing the trigger a second time turns off the solenoid after Burnback time. The bottom light indicates spot weld trigger mode. Closing the trigger allows a single, timed, weld cycle. The duration of the weld cycle is set with the time selection controls. The spot on timer starts when welding current flows.

TIME SELECTION CONTROLS. This control enables the operator to choose which timer will be displayed as shown by the indicator lights. Pressing the key causes the mode lights to sequence (from top to bottom). Any timers not available to the currently selected mode will be skipped. Times displayed in the LED display are adjusted using the setting adjustment arrows to the left of the LED display. The top left light indicates the preflow time is being displayed in seconds. The top right indicator light indicates the postflow time is being displayed in seconds. The middle light indicates the burnback time is being displayed in seconds. The bottom light indicates the spot weld time is being displayed in seconds.

LN-742 & LN-742H

B-3

OPERATION

B-3

FUNCTION SELECTION CONTROLS. This control

enables the operator to select the function that will be displayed as shown by the indicator lights. Pressing the key causes the mode lights to sequence (from top to bottom). Settings displayed in the LED display are adjusted using the setting adjustment arrows to the left of the LED display. The top light indicates the arc voltage is being displayed in volts. The middle light indicates the inch speed is being displayed. The bottom light indicates the weld feed speed (WFS) is being displayed.

INCREASE ARROW. This key increases the setting of the parameter selected to be displayed, using the “Quick-Set” feature for fast and accurate setting.

DECREASE ARROW. This key decreases the setting of the parameter selected to be displayed, using the “Quick-Set” feature for fast and accurate setting.

QUICK-SET FEATURE. This feature permits the arrow keys to control each display digit one at a time. The display digits blink in sequence from left to right. Pressing an arrow key immediately after a digit blinks alters that digit. Releasing the arrow key causes the left-to-right sequencing to resume.

COLD INCH KEY. This key energizes the wire feeder to inch the wire forward, but does not energize the power source or solenoid valve.

GAS PURGE KEY. This key energizes the solenoid valve to purge any remaining gasses, but does not energize the wire feeder or power source.

ENGLISH OR METRIC SPEED DISPLAY UNITS

Pressing both the Gas Purge key and Timer Selection key causes the speed display units to toggle between inches per minute (no decimal point displayed) or meters per minute (decimal point displayed). If the LED display is showing the voltmeter or one of the timer settings when these keys are pressed, the display will change to the weld speed to indicate the selected speed display units. See Figure B.1 for key locations.

CIRCUIT PROTECTION

The LN-742 has solid-state overload protection of the wire drive motor. If the wire drive motor becomes overloaded for an extended period of time, the protection circuitry turns off the power source, wire feeder, and solenoid, then displays the error code E30 on the LED display. This indicates the wire drive motor is overloaded, with the number indicating the time remaining in seconds before the unit will automatically reset. This number continues to decrement every second until it reaches zero. At that time the unit resets automatically and the previous display will return indicating that the unit is ready for operation.

Over loads can result from: improper tip size, liner, drive rolls, or guide tubes; obstructions or bends in the gun cable; feeding wire that is larger than the rated capacity of the feeder; or any other factors that would impede normal wire feeding.

ACCELERATION SETTING

Pressing both the Gas Purge key and the Function Selection key at the same time, on the keypad shown in Figure B.1, enables the acceleration setting display. The LED display will indicate “A-X” with “X” being a number from 1 (slowest) to 5 (fastest). This number is adjusted using the setting adjustment arrow keys. To exit the acceleration setting function, press both keys a second time, or press any other key except for the setting adjustment arrow keys.

LN-742 & LN-742H

DRIVE ROLL INSTALLATION

CHANGING DRIVE ROLLS FOR TWOROLL WIRE FEEDERS:

To change drive rolls on a two-roll wire feeder, refer to Figure B.2 and perform the following steps:

1. Turn off the welding power source.

2. Rotate the latch knob on the quick release arm.

B-4

GUIDE TUBE DETAIL

OUTGOING

GUIDE TUBE

INSERT

OUTGOING

GUIDE

TUBE

LARGE

RADIUS

DRIVE

ROLL

INCOMING

GUIDE

TUBE

SMALL

RADIUS

IDLE

ROLL

CLAMPING

COLLAR

SPACER (IF REQUIRED)

OUTPUT

SHAFT

DRIVE

ROLL

HALVES

OPERATION

FIGURE B.2 – INSTALLING DRIVE ROLLS ON A TWO-ROLL FEEDER.

B-4

LN-742 & LN-742H

B-5

OPERATION

B-5

3. Remove the hex head screw and clamping collar. Remove the drive roll from the shaft.

4. The new roll to be installed is stamped for the size wire to be fed. An “A” after the size indicates aluminum wire. Remove the rolls from the kit and wipe them clean. Wipe the output shaft and locating shoulder clean.

5. Use the clamping collar and hex head screw to install the roll on the output shaft. Certain size drive rolls consist of two roll halves, and may contain a spacer. If the drive roll you are installing contains a spacer, the spacer fits between the two halves of the drive roll. Tighten the hex head screw.

6. Back out the guide tube clamping screws. Remove the old guide tubes, if installed.

7. Insert the longer guide tube into the rear hole and the other guide tube through the front hole. The fine wire chisel point end of the guide tube must have the larger radius end next to the drive roll. See Figure B.2. Push the guide tube back as far as it will go and tighten the clamping screw. Insert the incoming guide tube as far back as it will go and tighten the clamping screw. The clamping screws are dog points. When the guide tubes are properly installed these dog points will lock into the annular grooves in each of the guide tubes.

8. Set the idle roll pressure as detailed in the Idle Roll Pressure Setting procedure detailed later in this section.

4. Loosen the thumb screws holding the guide tubes in place. Remove the incoming and outgoing guide tubes, if installed.

5. Remove the hex head screws and clamping collars from the output shafts. Remove the drive rolls and middle guide tube.

6. The new rolls to be installed are stenciled with the wire size that will be fed. An “A” after the number indicates aluminum wire. Remove the rolls from the kit and wipe them clean. Wipe the output shafts and locating shoulders clean.

7. Install one roll onto the output shaft closest to the incoming side of the feeder clamping collar and hex head screw. Certain size drive rolls consist of two roll halves, and may contain a spacer. If the drive roll you are installing contains a spacer, the spacer fits between the two halves of the drive roll. Tighten the hex head screw.

8. Install the middle guide tube, but do not tighten at this time. When installing a 0.035” middle guide tube the larger radius should be aligned towards the drive roll. Slide the guide tube up against the installed drive roll.

9. Install the second drive roll on the remaining shaft the same way as the first. Center the middle guide tube between the rolls and tighten the thumbscrews holding it in place.

10. Close and latch both quick release levers.

CHANGING DRIVE ROLLS FOR FOURROLL WIRE FEEDERS:

To change drive rolls on a four-roll wire feeder, refer to Figure B.3 and perform the following steps:

1. Turn off welding power source.

2. Remove the gun and cable from the conductor block on the feeder by loosening the hand screw and pulling the gun straight out of the block.

3. Open both quick release levers by moving the levers outward and pulling them toward you.

LN-742 & LN-742H

11. Slide the longer guide tube into the rear hole of the gearbox until it almost touches the drive roll and guide tube. Tighten the thumbscrew to hold it in place.

12. Install the outgoing guide tube into the front hole of the gearbox (through the conductor block) and tighten the thumb screw. The 0.035 in. outgoing guide tube should have the larger radius oriented toward the drive roll. For proper installation of the outgoing guide tube insert, refer to Figure B.3.

13. Be certain that the guide tubes do not touch the drive rolls or idle rolls. If they do touch, readjust them and tighten in place.

B-6

GUIDE TUBE DETAIL

OUTGOING

GUIDE TUBE

INSERT

OUTGOING

GUIDE

TUBE

MIDDLE

GUIDE

TUBE

SMALL

RADIUS

IDLE

ROLL

LARGE

RADIUS

CLAMPING

COLLAR

OUTPUT

SHAFT

SPACER

(IF REQUIRED)

DRIVE

ROLL

HALVES

OPERATION

FIGURE B.3 – INSTALLING DRIVE ROLLS ON A FOUR-ROLL FEEDER.

B-6

LN-742 & LN-742H

B-7

PRESSURE

ADJUSTMENT

KNOB

OPERATION

B-7

IDLE ROLL PRESSURE SETTING

The idle roll pressure is set at the factory. Two-roll feeders are set with the pressure adjustment knob backed out two turns from full pressure, and four-roll feeders are set backed out three turns. This is an approximate setting. For small wire sizes and aluminum wire the optimum idle roll pressure varies with type of wire, surface condition, lubrication, and hardness. The optimum idle roll setting can be determined as follows:

Two-roll wire feeders:

1. Press the end of the gun against a solid object that is electrically isolated from the welder output and press the trigger for several seconds.

2. If the wire “birdnests”, jams, or breaks at the drive roll, the idle roll pressure is set too high. Back the pressure adjustment knob, Figure B.4, out 1/2 turn. Run new wire through the gun and repeat step 1.

2. After outgoing pressure is set, determine how many turns away from full pressure the setting is.

3. Set both idle roll tensions to this setting. Engage both idle rolls before welding. For most applications, best wire feeding will occur when both idle roll pressures are set the same.

FIGURE B.4 – IDLE ROLL PRESSURE SETTING.

3. If the only result is drive roll slippage, loosen the gun cable clamping screw on the conductor block and pull the gun cable forward about six inches. There should be a slight waviness in the exposed wire. If there is no waviness, the pressure is too low. Increase the pressure setting 1/4 turn. Lock the gun cable in place and repeat steps 1 and 2.

Four-roll wire feeders:

1. Release the incoming idle roll and perform the pressure setting procedure for two roll feeders to set outgoing idle roll pressure.

LN-742 & LN-742H

B-8

2 IN. O.D. SPINDLE ADAPTER

RETAINING SPRING

BRAKE

HOLDING

GROOVES

READI-REEL

INSIDE CAGE WIRES THREADED

LOCKING

LLAR

OPERATION

B-8

WIRE LOADING

Loading a 22 to 30 Lb. (10 to 14 kg) Readi-Reel Package Using the Molded Plastic K363-P Readi-Reel Adapter:

The Spindle should be located in the LOWER mounting hole of the K1524-1 Universal Stand if used.

1) Depress the Release Bar on the Retaining Collar and remove it from the spindle. NOTE: Earlier spindles used a threaded collar. See Figure B.5a or B.5b.

2) Place the Adapter on the spindle.

3) Re-install the Retaining Collar. Make sure that the

Release Bar “pops up” and that the collar retainers fully engage the retaining groove on the spindle.

4) Rotate the spindle and adapter so the retaining

spring is at the 12 o'clock position.

5) Position the Readi-Reel so that it will rotate in a

direction when feeding so as to be de-reeled from the bottom of the coil.

6) Set one of the Readi-Reel inside cage wires on the slot in the retaining spring tab.

7) Lower the Readi-Reel to depress the retaining spring and align the other inside cage wires with the grooves in the molded adapter.

8) Slide the cage all the way onto the adapter until the retaining spring "pops up" fully.

WARNING

Check to be sure the Retaining Spring has fully returned to the locking position and has SECURELY locked the Readi-Reel Cage in place. Retaining Spring must rest on the cage, not the welding electrode.

___________________________________________

9) To remove Readi-Reel from Adapter, depress retaining spring tab with thumb while pulling the Readi-Reel cage from the molded adapter with both hands. Do not remove adapter from spindle.

FIGURE B.5a (Threaded Locking Collar)

FIGURE B.5b (Retaining Collar)

LN-742 & LN-742H

B-9

OPERATION

B-9

TO MOUNT 10 TO 44 lb (4.5 to 20 kg) SPOOLS (12 in./300 mm DIAMETER) OR 13-14 lb (6 kg)

INNERSHIELD COILS:

The spindle should be located in the lower mounting hole of the K1524-1 Universal Stand if used.

[For 8 in. (200 mm) spools, a K468 spindle adapter must first be slipped onto the spindle.]

[For 13 to 14 lb (6 kg) Innershield coils, a K435 Coil Adapter must be used.]

1. Depress the Release Bar on the Retaining Collar and remove it from the spindle. spindles used a threaded collar. See Figure B.5a or B.5b.

2. Place the spool on the spindle, making certain the spindle brake pin enters one of the holes in the backside of the spool. Be certain the wire comes off the reel in a direction so as to de-reel from the bottom of the coil.

3. Re-install the Retaining Collar. Make sure that the Release Bar “pops up” and that the collar retainers fully engage the retaining groove on the spindle.

ELECTRODE FEEDING AND BRAKE ADJUSTMENT

1. Turn the Readi-Reel or spool until the free end of the electrode is accessible.

NOTE: Earlier

2. While tightly holding the electrode, cut off the bent end and straighten the first six inches. Cut off the first inch. (If the electrode is not properly straightened, it may not feed or may not go into the outgoing guide tube, causing a “birdnest”.)

3. Insert the free end through the incoming guide tube.

4. Press the cold inch key or gun trigger and push the electrode into the drive roll.

WARNING

ELECTRIC SHOCK can kill.

• Do not touch electrically live parts such as output terminals or internal wiring.

• When inching with the gun trigger, electrode and drive mechanism are “hot” to work and ground and could remain “hot” for several seconds after the gun trigger is released.

------------------------------------------------------------------------

5. Inch the electrode through the gun.

6. Adjust the brake tension with the thumbscrew on the spindle hub until the reel turns freely but with little or no overrun when wire feeding is stopped. Do not overtighten.

LN-742 & LN-742H

B-10

SPINNER

NUT

COVER

PLATE

COIL

REEL

SLOTS CARDBOARD

COIL LINER

TIE WIRE SPRING

LOADED ARM

OPERATION

B-10

WIRE REEL LOADING – 50 AND 60 LB COILS (K303 OR K376 WIRE REEL STAND)

ADJUSTABLE WIRE REEL BRAKE

The mount for standard 50 and 60 pound electrode coils includes a two-position brake assembly. Generally the brake should be at the inner position (nearest to the wire reel shaft) for wire feed speeds below 400 in./min (10 m/min). It should be at the outer position for the faster wire speeds often used when feeding smaller diameter electrode.

To adjust the brake position, remove the wire reel. Pull the cotter pin that holds the brake shoe to the arm, move the shoe and replace the cotter pin. Do not bend the cotter pin - it is held in place by a friction fit.

TO MOUNT A 50 OR 60 LB COIL:

1. To remove the wire reel from its shaft, grasp the spring loaded knob and pull out. This straightens the knob so it seats into the shaft when released. Remove the reel.

CAUTION

Always be sure the free end of the coil is securely held while the tie wires are being cut and until the wire is feeding through the drive rolls. Failure to do this will result in “back lashing” of the coil, which may tangle the wire. A tangled coil will not feed. It must be untangled or discarded.

------------------------------------------------------------------------

8. Cut and remove only the tie wire holding the free end of the coil. Insert the free end into one of the holes in the cover and secure it by bending it back. Cut and remove the remaining tie wires.

9. Replace the reel on the wire feeder. Grasp the shaft knob, pull it out and swing it across the reel hub, locking the reel in place.

FIGURE B.6 – LOADING A 50 OR 60 LB COIL.

2. Lay the reel flat on the floor. Loosen the spinner nut and remove the cover plate. See Figure B.6.

3. Place the coil of electrode on the reel so it unwinds as the reel rotates clockwise. DO NOT cut the tie wires at this time.

4. Be sure the coil is placed so the spring loaded arms will not interfere with the later removal of the coil tie wires.

5. When loading 0.030 to 0.045” electrode, be certain the coil is placed on the reel so the spring loaded arms are at the center of the slots in the cardboard coil liner. This provides the positive compression of the coil sides needed for troublefree wire feeding.

6. Put the cover plate on the reel so the four arms of the cover plate straddle and are in line with the spring loaded arms of the reel.

7. Tighten the cover as much as possible by hand. DO NOT hammer on the spinner nut arms.

LN-742 & LN-742H

B-11

SPINNER NUT

COVER PLATE

SLOTS

CARDBOARD COIL LINER

COIL

TIE WIRE

SPRING LOADED ARM

REEL

OPERATION

B-11

WIRE REEL LOADING – 50 AND 60 LB COILS (K1524-1 UNIVERSAL WIRE REEL STAND)

TO MOUNT A 50 to 60 lb (22.7 to 27.2 kg) COIL: (USING K1504-1 COIL REEL) (FOR 50 to 60 lb READI-REELS A K438 READI-REEL ADAPTER MUST BE USED.)

The spindle should be located in the UPPER mounting hole.

1. With the K-1504-1 Coil Reel mounted on the 2 in. (51 mm) spindle (or with reel laying flat on the floor) loosen the spinner nut and remove the reel cover. See Figure B.7.

2. Before cutting the tie wires, place the coil of electrode on the reel so it unwinds from the bottom as the reel rotates.

3. Tighten the spinner nut against the reel cover as much as possible by hand, using the reel cover spokes for leverage. DO NOT hammer on the spinner nut arms.

FIGURE B.7 – K1504-1 COIL REEL.

4. Cut and remove only the tie wire holding the free end of the coil. Hook the free end around the rim of the reel cover and wrap it around to secure. Cut and remove the retaining tie wires.

CAUTION

Always be sure the free end of the coil is securely held while the tie wires are being cut and until the wire is feeding through the drive rolls. Failure to do this will result in “backlash” of the coil, which may tangle the wire. A tangled coil will not feed, so it must either be untangled or discarded.

____________________________________

5. Be sure the coil is engaged with the spindle brake pin and the Release Bar and Retaining Collar “pops up” and that the collar retainers fully engage the retaining groove on the spindle.

LN-742 & LN-742H

B-12

OPERATION

B-12

MAKING A WELD

1. Use only constant voltage power type sources. If using a multiple process power source, be sure it is set for constant voltage output per instructions in the manual for the power source.

2. Set the power source polarity switch or properly connect the electrodes and work leads for the correct electrode polarity.

3. Set the voltage using the control on the power source or, if used, the optional K589-1 Remote Kit or K857 Remote Voltage Control. Set the open circuit voltage to approximately 2 volts higher than the desired procedure voltage. The final setting must be made according to the arc voltage while welding.

4. Use the Mode Selection key to set the desired operating mode.

5. Use the Function Selection key and Selection Setting arrow keys to set the desired Inch and Weld Feed speeds.

6. Use the Time Selection key and Selection Setting arrow keys to set the desired timers.

7. Inch the electrode through the gun and cable. For solid wire, cut the electrode within approximately 3/8 in. of the end of the contact tip. If using cored wire, cut the electrode within 3/4 in. of the extension guide.

8. Connect the work cable to the metal to be welded. The work cable must make good electrical contact with the work. The work must also be grounded.

9. Position the electrode over the joint. The end of the electrode may be lightly touching the work.

10. Lower your welding helmet. Close the gun trigger and begin welding. Hold the gun so the contact tip to work distance gives the correct electrical stickout as required for the procedure being used.

11. To stop welding, release the gun trigger and then pull the gun away from the work after the arc goes out.

WIRE REEL CHANGING

At the end of a coil, remove the last of the old electrode from the conductor cable. Either pull it out at the nozzle, or use the following procedure:

1. Cut off the end of the electrode at the gun end. Do not break it off by hand. Breaking by hand puts a slight bend in the wire, making it difficult to pull it back through the nozzle.

2. Uncouple the gun conductor cable from the conductor block on the wire feeder drive unit and lay the gun cable out straight.

3. Using pliers, grip the wire and pull it out of the cable from the connector end.

4. After the electrode has been removed, connect the gun conductor back to the wire feeder.

5. Load a new reel of electrode per the instructions for the specific reel type given previously in this section.

WARNING

When using an open arc process, it is necessary to use correct eye, head, and body protection.

------------------------------------------------------------------------

LN-742 & LN-742H

C-1

ACCESSORIES

GENERAL

The following is a list of the accessories that can be used with the LN-742 wire feeder.

TABLE C.1 – LN-742 ACCESSORIES.

Product Number Name

K163 Undercarriage K178-1 Mounting Platform K589-1 Remote Control Kit K590-1 Water Solenoid Kit K590-2 Water Connection Kit K857 Remote Voltage Control Kit K58 Magnetic Separator K310 Flux Screen K320 Flux Tank K619 Input Cable - 350 Amps K112 Submerged Arc Welding Gun - 500 Amps K115 Innershield Welding Gun - 400 Amps K126 Innershield Welding Gun - 350 Amps K470 Magnum GMA Welding Gun - 200 Amps K471 Magnum GMA Welding Gun - 300 Amps K497 Magnum GMA Welding Gun - 400 Amps K162H Spindle K363P 22 to 30 lb Readi-Reel Adapter K376 and 303 50 to 60 lb Wire Reel Mounting Stands K1524-1 Universal Wire Reel Stand - 2” Spindle K1504-1 60 lb Coil Adapter for K1524-1 Stand K1551-1 Insulated Lift Bail for K1524-1 Stand K1556-1 Caster Kit for K1524-1 Stand K1557-1 Swivel Platform for K1524-1 Stand K1819-25 Control Cable Assembly 25 Ft. K1819-50 Control Cable Assembly 50 Ft. K1819-75 Control Cable Assembly 75 Ft. K1819-100 Control Cable Assembly 100 Ft. K377 Small Mounting Stand for Readi-Reel Coils and 22 to 30 lb Spindle with 2 in. O.D. K378 Small Mounting Stand for 13 to 14 lb Innershield Coils K435 Spindle Adapter for 14 lb Coils K438 50 to 60 lb Readi-Reel Adapter K445 Mounting Stand for Readi-Reel Coils and 50 to 60 lb Spindle with 2 in. O.D. K468 Spindle Adapter for 8 in. O.D. Spools M11514 Wire Reel Dust Shield Door for K303 and K376 S14543 Wire Reel Dust Shield for K376 50 to 60 lb Wire Reel Mounting Stand

A detailed description of each item is given later in this section.

C-1

LN-742 & LN-742H

C-2

ACCESSORIES

C-2

K163 UNDERCARRIAGE

The undercarriage includes casters, wheels, a handle, and related hardware. Casters are mounted at the front and wheels at the rear of the platform. The handle is bolted to the front of the platform so the wire feeder can be tilted back and wheeled like a two-wheel truck. Installation sheet M13424 is provided with the undercarriage.

K178-1 MOUNTING PLATFORM

This is a turntable type platform for mounting the LN742 to the top of Idealarc power sources. Bolt the platform to the lift bail per the instructions (M16260) supplied with the platform.

K589-1 REMOTE CONTROL KIT

Provides remote potentiometer control of weld speed and arc voltage up to 16.4 ft (5.0 m) from the wire feeder. Power source must have remote control capability. (K856 Power Source Remote Kit required for CV-300/400-I, and smaller CV- Model machines below Code 9900.) Install K589-1 Kit per S20520 installation instructions provided with the kit.

K590-1 WATER SOLENOID KIT

K857 can be installed on the LN-742 when it is used with newer Lincoln power sources that are equipped with a 6-socket ms-type receptacle or K864 14-pin connector adapter for connection of the plug on the 28 ft (8.5 m) control cable of the K857. See the instructions (S19103) included with the kit.

FLUX SYSTEM COMPONENTS

The flux system is available to permit the LN-742 to be used for submerged arc welding. It is comprised of the components described below.

K58 MAGNETIC SEPARATOR

The K58 is a permanent magnet type separator designed to fit the top of the standard fill funnel of the continuous flux feeding system.

The purpose of the separator is to remove magnetic materials such as mill scale and any other extraneous magnetic materials which may have been recovered along with the flux to be processed.

It is important to remove these magnetic particles from the flux which is to be used in the continuous flux feeding systems. If the magnetic material is not removed it will gather around the nozzle of the gun and impede or shut off the flux flow when making relatively long welds or welding continuously. The magnetic particles can also cause porosity in the weld.

Includes a solenoid valve already attached to a mounting bracket and supply connection manifold assembly for easy installation on the upper rear panel of the LN-742 case. Also includes water-cooled gun tube fittings and self-sealing outlet and inlet quickconnectors for mounting to the front of the LN-742 case.

K590-2 WATER CONNECTION KIT

This kit is the same as the K590-1 except that it does not include the solenoid for water coolers requiring continuous flow.

K857 REMOTE VOLTAGE CONTROL KIT

Installs on the side of the LN-742 control box cover and gives voltage control at the wire feeder.

K310 FLUX SCREEN

The unit was designed to fit the top of either the standard fill funnel or a K58 magnetic separator. The unit has a steel screen with 0.065 to 0.075 in. openings and an air vibrator attached to the frame. The vibrator can be used with air line pressures ranging from 20 through 100 psi.

For ease of handling, the user should connect the incoming air line to the 1/8 in. pipe elbow with the aid of a quick disconnect type air coupling.

It is very important that reclaimed flux to be used in the continuous flux feeding system be passed through the K310 screen or its equivalent.

LN-742 & LN-742H

C-3

ACCESSORIES

C-3

K320 FLUX TANK

Either turn off the incoming air line or remove the quick disconnect if one has been installed. Slightly loosen the tank cap and let the air in the tank escape in the holes in the side of the cap. After pressure has been released, remove the cap from the tank. Using the funnel provided, put 100 pounds of flux in the tank. It is very important that only new or properly reclaimed flux be put in the tank. Coarse particles and/or magnetic particles will stop the flux feeding process. New Lincoln flux is properly screened at the factory. All reclaimed flux must be separately screened through a vibrating screen with 0.065 in. to 0.075 in. openings and be put through a magnetic separator. The K310 vibrated screen and K58 magnetic separator are available for this purpose. The screen in the funnel supplied with the tank has much larger openings and its only purpose is to keep paper and slag out of the tank.

There will always be a small amount of air and possible drops of water coming out of the end of the tube coiled under the tank. This is an automatic disposal system in case the plant air has water and dirt in it.

POWER INPUT CABLES

A variety of power input cable assemblies are available for various current ratings and power source connection types. All provide a polarized control cable plug and a lugged electrode cable for connection to the wire feeder.

WELDING GUNS

Welding guns can be broken down into groups, according to the type of welding that is to be accomplished. Select the appropriate welding gun from the following weld-type groups.

INNERSHIELD GUNS

K122. This submerged arc gun and its cable assem-

blies are rated 500 amps, 60% duty cycle. K115. This Innershield gun and its cable assemblies

are rated at 450 amps, 60% duty cycle. Maximum wire size for LN-742 models is 5/64 in. (2.0 mm).

K126. This Innershield gun and its cable assemblies are rated at 350 amps, 60% duty cycle. Maximum wire size for LN-742 models is 5/64 in. (2.0 mm).

NOTE: The K115 and K126 are not recommended for LN-742H models.

NOTE: Linconditioner locations where smoke accumulation is a problem and conventional exhaust systems are ineffective. The available smoke removal type Innershield guns and vacuum units can be used in these locations. Instructions are shipped with the equipment.

guns are recommended for

K1819-[ ] CONTROL CABLES

These control cables connect the wire feeder to the power source.The wire feeder end is an 8 pin anphenol and the power source end is a 14 pin amphenol. The control cable supplies 42VAC from the welding power source to the feeder. It also carries a lead for the work voltage and sends signals for the gun trigger and remote voltage potentiometer. See connection diagram of wire feeder to power source in the “Installation Section”.

K1817-[ ] CONTROL CABLE EXTENSIONS

The control cable extensions are used to lengthen the control cable. The extensions have a 14 pin amphenol on one end that connects to the K1819-[ ] cable and the other end has a 14 pin amphenol that connects to the welding power source. Do not exceed more than 100 Ft. (31m) of total control length. See connection diagram of wire feeder to power source in the

“Installation Section”.

LN-742 & LN-742H

C-4

ACCESSORIES

C-4

SUBMERGED ARC GUNS

The K112 gun and cable assembly is recommended for welding with 1/16 in. solid steel electrode at up to 500 amps. Gun cable length is 15 feet.

GMAW GUNS

An expanding line of Magnum GMA gun and cable assemblies are available to allow welding with solid and cored electrodes using the GMAW process. See the appropriate Magnum literature for descriptions of the 200-400 ampere air cooled guns and cables that are available. Gun cable lengths range from 10 to 25 ft. (3.0 to 7.5 m) and feed electrode sizes 0.025 in. to 5/64 in. (0.6 to 2.0 mm).

SPINDLES, STANDS, AND ADAPTERS

There are a variety of spindles and wire reel adapters available for use with the LN-742. Select the desired setup according to your specific welding needs.

K162H SPINDLE

The K162H spindle is used for mounting Readi-Reels and 2 in. I.D. spools with a 60 lb capacity on a K303 or K376 Wire Reel Stand. When used with Readi-Reels, a Readi-Reel Adapter is required. For 8 in. O.D. spools, a K468 Spindle Adapter is available.

K363P 22 TO 30 LB READI-REEL ADAPTER

Adapts Lincoln Readi-Reel coils of 22 and 33 lb (10 and 14 kg) to a 2 in. (51 mm) spindle. Durable, molded plastic, one piece construction. Designed for easy loading -- adapter remains on spindle for quick changeover. (Included with K377.)

UNIVERSAL WIRE REEL STAND (K1524-1)

Includes a 2" (51mm) O.D. Spindle with adjustable brake and two locations for mounting the spindle to allow for the mounting of 50 - 60lb, 10 - 30 lb, 13 14lb, and 8" O.D. coils with proper spindle adapters. (See OPERATION section) Capable of being mounted on the top of a suitable power source or surface without the need for any other mounting kit. Optional features available for this stand include:

• K1555-1 insulated lift bale

• K1556-1 caster kit

• K1557-1 swivel platform.

60 LB. (27.2 KG) COIL ADAPTER (K1504-1)

Permits 50-60 lb. (22.7-27.2 Kg) coils to be mounted to a 2" (51mm) spindle.

K1551-1 INSULATED LIFT BALE: Provides a

bolt on lift bale with an electrically insulated lift hook.

K1556-1 CASTER KIT: Comes with 4 light duty

2" O.D. casters which mount in place of the rubber feet on the wire stand. Use in light duty applications where portability is required. Can be used in combination with the K1557-1 swivel platform.

K1557-1 SWIVEL PLATFORM: Allows for the

mounting of the wire feeder reel stand assembly on top of a suitable power source if the need for the wire feeder reel stand assembly to swivel is desired. Also has mounting holes in the base feet for mounting to any surface that it can be fastened to. Comes with a rotating tool tray to hold gun tips, guide tubes, drive rolls, etc. Will work in combination with the K1556-1 caster kit.

K376 AND K303 50 TO 60 LB WIRE REEL MOUNTING STANDS

The K376 50 to 60 lb Wire Reel Mounting Stand and the K303 Wire Reel Mounting Stand are the same with the exception that the K303 stand includes a dust shield. The assembly includes a framework to which is attached the 50 to 60 lb wire reel, a mounting spindle, a lift bale, and a cable clamp for fastening the input cable assembly. It is easily mounted to the basic wire feed unit by following the Attaching the Wire Reel Stand procedure at the end of this section.

LN-742 & LN-742H

C-5

ACCESSORIES

C-5

K377 SMALL MOUNTING STAND FOR READI-REEL COILS AND 22 TO 30 LB SPINDLE WITH 2 IN. I.D.

This assembly includes a wire reel spindle (similar to the K162 spindle) attached to a small frame. The unit is supplied with the K363 Readi-Reel Adapter for using the Lincoln “Readi-Reel Electrode Coils”. Without the adapter the unit is capable of handling spools with a 2 in. I.D., a 12 in. maximum O.D., and a 4 in. width. For spools with an 8 in. O.D., a K468 spindle adapter is available. The spindle has an adjustable braking system. See Attaching the Wire Reel Stand procedure at the end of this section for installation procedures.

K378 SMALL MOUNTING STAND FOR 13 TO 14 LB INNERSHIELD COILS

This assembly includes the same smaller frame as used in the K377 and the fully enclosed canister system for dereeling of the 14 lb coil. This system has a fixed brake for the 14 lb coil. See Attaching the Wire Reel Stand Procedure at the end of this section for installation procedures.

K468 SPINDLE ADAPTER FOR 8 IN. O.D. SPOOLS

Permits 8 in. (203 mm) O.D. spools to be mounted on 2 in. (51 mm) O.D. spindles. For K377 and K445, or K303 and K376 with optional K162H adapter.

M11514 WIRE REEL DUST SHIELD DOOR FOR K303 AND K376

In extremely dusty and dirty locations this door kit can be added to those units having the dust shield kit (S14543). This door kit includes a hinged door and sliding bottom seal. When these parts are attached to the reel support per the instructions included, the unit becomes a completely enclosed housing. Order part no. M11514.

S14543 WIRE REEL DUST SHIELD FOR K376 50 TO 60 LB WIRE REEL MOUNTING

STAND

A shield is available to cover the wire and reel to protect the wire from falling dirt and dust. Order part no. S14543. Instructions are provided with the kit.

K435 SPINDLE ADAPTER FOR 14 LB COILS

Permits 14 lb (6 kg) Innershield coils to be mounted on 2 in. (51 mm) O.D. spindles. For K377 and K445, or K303 and K376 with optional K162H adapter.

K438 50 TO 60 LB READI-REEL ADAPTER

Adapts Lincoln Readi-Reel coils of 50 to 60 lb (22.7 to

27.7 kg) to a 2 in. (51 mm) spindle. (Included with K445.)

K445 MOUNTING STAND FOR READIREEL COILS AND 50 TO 60 LB SPINDLE WITH 2 IN. O.D.

50 to 60 lb (22.7 to 27.7 kg) Readi-Reel mounting stand. This assembly includes framework that a 2 in. (51 mm) O.D. spindle with adjustable brake and 50 to 60 lb (22.7 to 27.7 kg) (K438) Readi-Reel adapter. Includes a lift bail and cable clamp for fastening the input cable assembly. Does not include a dust shield. A dust shield that covers the wire reel and protects the wire from falling dirt and dust is available for this unit. Order part number S14543. This unit will accept the M11514 door kit (see K303) but only if already equipped with optional dust shield (S14543).

ATTACHING THE WIRE REEL STAND

The mounting hardware for mounting the stands is included with the LN-742. Screws and washers are inserted in their respective mounting holes. To connect:

1. Remove the three 3/8 in. hex head bolts from the back of the wire feed unit.

2. Place the wire reel mounting stand mounting bracket in position against the back of the wire feed unit.

3. Replace and tighten the hex head bolts. The long screw and plain washer go into the top hole.

LN-742 & LN-742H

C-6

ACCESSORIES

DRIVE ROLL KITS

Table C-2 lists the appropriate drive roll kits for each type of wire used.

TABLE C.2 – DRIVE ROLL KIT NUMBERS.

2-Roll 4-Roll

Steel Wire Sizes

0.068-3/32 in. (1.7-2.4 mm) Cored KP653-3/32C KP655-3/32C 1/16 in. (1.6 mm) Cored or Solid KP653-1/16 KP655-1/16

0.045-0.052 in. (1.2-1.3 mm) Solid KP653-052S KP655-052S

0.045-0.052 in. (1.2-1.3 mm) Cored KP653-052C KP655-052C

0.035 in. (0.9 mm) Solid KP653-035S KP655-035S

0.035 in. (0.9 mm) Cored KP653-035C KP655-035C

0.030 in. (0.8 mm) Solid KP653-030S KP655-030S

0.023-0.025 in. (0.6 mm) Solid KP653-025S KP655-025S Aluminum Wire Sizes 1/16 in. (1.6 mm) KP654-1/16A KP656-1/16A 3/64 in. (1.2 mm) KP654-3/64A KP656-3/64A

0.035 in. (0.9 mm) KP654-035A KP656-035A

C-6

LN-742 & LN-742H

D-1

MAINTENANCE

D-1

ROUTINE MAINTENANCE

DRIVE ROLLS AND GUIDE TUBES

After feeding every coil of wire, inspect the drive roll section. Clean the assembly as necessary. Do not use solvent to clean the drive roll assembly as it may wash the lubricant out of the bearings. The drive rolls and guide tubes are stamped with the wire sizes they will feed. If a wire size other than that stamped on the rolls is to be used, the rolls and guide tubes must be changed.

The drive rolls for 0.045 and 0.052 cored electrode and 1/16, 0.068, 5/64, 3/32, and 7/64 electrode have a double set of teeth so they can be reversed for additional life. Drive rolls for 0.023 through 0.052 solid electrodes have no teeth.

Refer to the instructions in Section B, Operation for installation of drive rolls.

WIRE REEL MOUNTING

No routine maintenance is required for Readi-Reels and 10 to 30 lb spools. Do not lubricate the 2 in. spindles.

PERIODIC MAINTENANCE

WIRE DRIVE MOTOR AND GEARBOX

Every year inspect the gearbox and coat the gear teeth with a moly-disulfide filled grease. Do not use graphite grease.

Every six months check the motor brushes. Replace them if they are less than 1/4 in. long.

GUN AND CABLE MAINTENANCE

For instructions on periodic maintenance for the welding gun and cables, refer to the instructions included with your specific model of welding gun.

To prolong the life of the reel shaft on the 50 to 60 lb coils, periodically coat it with a thin layer of grease. No maintenance to the two position brake is required. If the brake shoe wears through to metal, replace the brake assembly.

LN-742 & LN-742H

E-1

TROUBLESHOOTING

HOW TO USE TROUBLESHOOTING GUIDE

WARNING

Service and Repair should only be performed by Lincoln Electric Factory Trained Personnel. Unauthorized repairs performed on this equipment may result in danger to the technician and machine operator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, please observe all safety notes and precautions detailed throughout this manual.

__________________________________________________________________________

E-1

This Troubleshooting Guide is provided to help you locate and repair possible machine malfunctions. Simply follow the three-step procedure listed below.

Step 1. LOCATE PROBLEM (SYMPTOM).

Look under the column labeled “PROBLEM (SYMPTOMS)”. This column describes possible symptoms that the machine may exhibit. Find the listing that best describes the symptom that the machine is exhibiting.

Step 2. POSSIBLE CAUSE.

The second column labeled “POSSIBLE CAUSE” lists the obvious external possibilities that may contribute to the machine symptom.

WARNING

ELECTRIC SHOCK can kill.

• Do not touch electrically live parts such as internal wiring.

Step 3. RECOMMENDED COURSE OF ACTION

This column provides a course of action for the Possible Cause, generally it states to contact your local Lincoln Authorized Field Service Facility.

If you do not understand or are unable to perform the Recommended Course of Action safely, contact your local Lincoln Authorized Field Service Facility.

• Only qualified personnel should install, use or ser-

vice this equipment.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

E-2

PROBLEMS

(SYMPTOMS)

TROUBLESHOOTING

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

E-2

The display is blank. No wire feed when the gun trigger is activated.

No wire feed when the gun trigger is activated. The solenoid does not function. No arc voltage present. The display board indicates the LN-742 has input power applied.

1. Make sure the control cable is

connected to the welding power source correctly.

2. Make sure the welding power

source is turned on and functioning properly.

3. Check the 42 VAC fuse or cir-

cuit breaker in the welding power source.

1. Check or replace the gun trigger

switch.

2. Check the gun trigger recepta-

cle. Check for loose or faulty connections.

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact

your local Lincoln Authorized Field Service Facility.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

E-3

PROBLEMS

(SYMPTOMS)

TROUBLESHOOTING

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

E-3

When the gun trigger is activated the wire feed motor runs and the solenoid functions but no arc voltage is present.

The wire feeds when the gun trigger is activated but there is no control of the wire feed speed.

1. Make sure the welding power

source is functioning properly. Disconnect the control cable from the Lincoln power source. Place a jumper across sockets C and D of the 14 pin amphenol plug at the power source. Open circuit voltage should be present at the welder output terminals. If no voltage is present at the output terminals the power source is faulty.

2. The control cable may be faulty.

Check leads #2 and #4 (pins C and D) for continuity (zero ohms).

3. The welding cables may me

faulty. Check for loose or faulty connections.

4. The gun may be faulty. Check

or replace.

1. Check for loose or faulty con-

nections between the tach and the control board plug J3.

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact

your local Lincoln Authorized Field Service Facility.

The wire feed speed does not change when welding current begins to flow.

1. The inch and weld speeds may

be set to the same value.

2. If the display shows the ----

symbol the inch speed has been disabled. To enable the inch speed press the increase arrow key.

3. Check plug J2 on the control

board for loose or faulty connections.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

E-4

PROBLEMS

(SYMPTOMS)

TROUBLESHOOTING

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

E-4

The LN-742 voltmeter does not function or read correctly when the actual arc voltage is present. The wire feeder is feeding wire correctly.

The LN-742 shuts down while welding and the HXX symbol appears on the display.

The display and/or indicator lights do not change when the arrow or select keys are pressed.

1. Make sure the polarity switch on

the Lincoln welding power source is in the correct position for the welding process.

2. Check or replace the control

cable. Check the continuity (zero ohms) of leads #21 and #67.

1. Check for mechanical restric-

tions in the wire feed path.

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact

your local Lincoln Authorized Field Service Facility.

1. Make sure the control cable is

connected to the welding power source correctly.

2. Check the 42 VAC fuse or cir-

cuit breaker in the welding power source.

The arrow keys do not change the welding wire feed speed.

1. If a remote control unit is con-

nected to the LN-742 the arrow keys will not change welding wire feed speed. Use the WFS pot on the remote control unit or disconnect the remote control unit and use the arrow keys.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

E-5

PROBLEMS

(SYMPTOMS)

TROUBLESHOOTING

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

E-5

The purge key does not activate the gas solenoid. The solenoid does activate when the gun trigger is pulled.

The gas solenoid does not activate either when the purge key is pressed or when the gun trigger is pulled.

The cold inch key does not activate the wire feed motor. The wire feed motor operates normally when the gun trigger is pulled.

The HI symbol appears on the display when the voltmeter function is selected.

The Er symbol appears on the display.

1. Contact your local Lincoln

Authorized Field Service Facility.

1. Check plug J6, located on the

control board for loose or faulty connections.

1. Contact your local Lincoln

Authorized Field Service Facility.

1. If the arc voltage is greater than

44 VDC, this is a normal condition. The voltmeter only reads 0-44 VDC.

1. This is an EPROM error. The

parameter recalled at power-up is out of range. Press any key to reset unit. Check all weld settings before proceeding with weld.

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact

your local Lincoln Authorized Field Service Facility.

The EXX appears on the display. (XX is some number from 1 to 10.)

The EP symbol appears on the display.

The uP symbol appears on the display. (Microprocessor RAM error.)

1. Remove input power to the

feeder (42 VAC). Wait 5 seconds. The symbol should not reappear when power is returned.

1. Remove input power to the

feeder (42 VAC). Wait 5 seconds. The symbol should not reappear when power is returned.

1. Remove input power to the

feeder (42 VAC). Wait 5 seconds. The symbol should not reappear when power is returned.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

E-6

PROBLEMS

(SYMPTOMS)

TROUBLESHOOTING

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

E-6

The wire is feeding rough or not feeding. The drive rolls are turning.

The drive rolls do not turn when the gun trigger is pressed. The gas solenoid activates and arc voltage is present.

1. Check for mechanical restric-

tions in the wire feeding path. Check the gun and gun components.

2. Check the drive roll position and

idle roll pressure.

3. The electrode may be dirty or

rusty.

4. Check for the correct gun liner,

tip, and guide tubes.

1. Check plug J5 on the control

board for loose or faulty connections.

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact

your local Lincoln Authorized Field Service Facility.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

E-7

PROBLEMS

(SYMPTOMS)

TROUBLESHOOTING

Observe all Safety Guidelines detailed throughout this manual

POSSIBLE

CAUSE

RECOMMENDED

COURSE OF ACTION

E-7

The welding arc is variable or “hunting”.

Poor arc striking with sticking or “blast-offs”. The weld bead may be ropy and narrow.

1. Check the welding cables for

loose or faulty connections.

2. Make sure the wire feed speed,

voltage, polarity and shielding gas are correct for the process being used.

3. Check for mechanical restric-

tions in the wire feed path.

4. Make sure the welding power

source is functioning properly.

1. Make sure the wire feed speed,

voltage, polarity and shielding gas are correct for the process being used.

2. Make sure the welding power

source is functioning properly.

3. Make certain the gas solenoid is

operating properly and the gas flow rate is correct for the procedure.

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact

your local Lincoln Authorized Field Service Facility.

4. The welding gun may be faulty.

Check for gas leaks or replace gun.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your

Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

LN-742 & LN-742H

F-1

DIAGRAMS

F-1

LN-742 & LN-742H

NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The specific diagram for a particular code is pasted inside

the machine on one of the enclosure panels. If the diagram is illegible, write to the Service Department for a replacement. Give the equipment code number..

NOTES

LN-742 & LN-742H

NOTES

LN-742 & LN-742H

F-4

NOTES

F-4

LN-742 & LN-742H

F-5

NOTES

F-5

LN-742 & LN-742H

WARNING

Spanish

AVISO DE

PRECAUCION

● Do not touch electrically live parts or

electrode with skin or wet clothing.

● Insulate yourself from work and

ground.

● No toque las partes o los electrodos

bajo carga con la piel o ropa mojada.

● Aislese del trabajo y de la tierra.

● Keep flammable materials away.

● Mantenga el material combustible

fuera del área de trabajo.

● Wear eye, ear and body protection.

● Protéjase los ojos, los oídos y el

cuerpo.

French

ATTENTION

German

WARNUNG

Portuguese

ATENÇÃO

Japanese

Chinese

Korean

Arabic

● Ne laissez ni la peau ni des vête-

ments mouillés entrer en contact avec des pièces sous tension.

● Isolez-vous du travail et de la terre.

● Berühren Sie keine stromführenden

Teile oder Elektroden mit Ihrem Körper oder feuchter Kleidung!

● Isolieren Sie sich von den

Elektroden und dem Erdboden!

● Não toque partes elétricas e elec-

trodos com a pele ou roupa molhada.

● Isole-se da peça e terra.

● Gardez à l’écart de tout matériel

inflammable.

● Entfernen Sie brennbarres Material!

● Mantenha inflamáveis bem guarda-

dos.

● Protégez vos yeux, vos oreilles et

votre corps.

● Tragen Sie Augen-, Ohren- und Kör-

perschutz!

● Use proteção para a vista, ouvido e

corpo.

READ AND UNDERSTAND THE MANUFACTURER’S INSTRUCTION FOR THIS EQUIPMENT AND THE CONSUMABLES TO BE USED AND FOLLOW YOUR EMPLOYER’S SAFETY PRACTICES.

SE RECOMIENDA LEER Y ENTENDER LAS INSTRUCCIONES DEL FABRICANTE PARA EL USO DE ESTE EQUIPO Y LOS CONSUMIBLES QUE VA A UTILIZAR, SIGA LAS MEDIDAS DE SEGURIDAD DE SU SUPERVISOR.

LISEZ ET COMPRENEZ LES INSTRUCTIONS DU FABRICANT EN CE QUI REGARDE CET EQUIPMENT ET LES PRODUITS A ETRE EMPLOYES ET SUIVEZ LES PROCEDURES DE SECURITE DE VOTRE EMPLOYEUR.

LESEN SIE UND BEFOLGEN SIE DIE BETRIEBSANLEITUNG DER ANLAGE UND DEN ELEKTRODENEINSATZ DES HERSTELLERS. DIE UNFALLVERHÜTUNGSVORSCHRIFTEN DES ARBEITGEBERS SIND EBENFALLS ZU BEACHTEN.

● Keep your head out of fumes.

● Use ventilation or exhaust to

remove fumes from breathing zone.

● Turn power off before servicing.

● Do not operate with panel open or

guards off.

WARNING

● Los humos fuera de la zona de res-

piración.

● Mantenga la cabeza fuera de los

humos. Utilice ventilación o aspiración para gases.

● Gardez la tête à l’écart des fumées.

● Utilisez un ventilateur ou un aspira-

teur pour ôter les fumées des zones de travail.

● Vermeiden Sie das Einatmen von

Schweibrauch!

● Sorgen Sie für gute Be- und

Entlüftung des Arbeitsplatzes!

● Mantenha seu rosto da fumaça.

● Use ventilação e exhaustão para

remover fumo da zona respiratória.

● Desconectar el cable de ali-

mentación de poder de la máquina antes de iniciar cualquier servicio.

● Débranchez le courant avant l’entre-

tien.

● Strom vor Wartungsarbeiten

abschalten! (Netzstrom völlig öffnen; Maschine anhalten!)

● Não opere com as tampas removidas.

● Desligue a corrente antes de fazer

serviço.

● Não toque as partes elétricas nuas.

● No operar con panel abierto o

guardas quitadas.

● N’opérez pas avec les panneaux

ouverts ou avec les dispositifs de protection enlevés.

● Anlage nie ohne Schutzgehäuse

oder Innenschutzverkleidung in Betrieb setzen!

● Mantenha-se afastado das partes

moventes.

● Não opere com os paineis abertos

ou guardas removidas.

Spanish

AVISO DE

PRECAUCION

French

ATTENTION

German

WARNUNG

Portuguese

ATENÇÃO

Japanese

Chinese

Korean

Arabic

LEIA E COMPREENDA AS INSTRUÇÕES DO FABRICANTE PARA ESTE EQUIPAMENTO E AS PARTES DE USO, E SIGA AS PRÁTICAS DE SEGURANÇA DO EMPREGADOR.

• World's Leader in Welding and Cutting Products •

• Sales and Service through Subsidiaries and Distributors Worldwide •

Cleveland, Ohio 44117-1199 U.S.A. TEL: 216.481.8100 FAX: 216.486.1751 WEB SITE: www.lincolnelectric.com

Lincoln LN-742, LN-742H User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual