Lincoln Electric SVM132-A Troubleshooting & Repair, PC Board Troubleshooting Procedures

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TROUBLESHOOTING & REPAIR

PC BOARD TROUBLESHOOTING PROCEDURES

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WARNING

ELECTRIC SHOCK can kill.

•Have an electrician install and service this equipment. Turn the input power OFF at the fuse box before working on equipment. Do not touch electrically hot parts.

CAUTION

Sometimes machine failures appear to be due to PC board failures. These problems can sometimes be traced to poor electrical connections. To avoid prob- lems when troubleshooting and replacing PC boards, please use the following procedure:

1.Determine to the best of your technical ability that the PC board is the most likely component causing the failure symptom.

2.Check for loose connections at the PC board to assure that the PC board is properly connected.

3.If the problem persists, replace the suspect PC board using standard practices to avoid static electrical damage and electrical shock. Read the warning inside the static resistant bag and perform the following procedures:

PC board can be damaged by static electricity.

-Remove the PC board from the static-shielding bag and place it directly into the equipment. Don’t set the PC board on or near paper, plastic or cloth which could have a static charge. If the PC board can’t be installed immediately, put it back in the static-shield- ing bag.

-If the PC board uses protective shorting jumpers, don’t remove them until installation is complete.

-If you return a PC board to The Lincoln Electric Company for credit, it must be in the static-shielding bag. This will prevent further damage and allow proper failure analysis.

4.Test the machine to determine if the failure symptom has been corrected by the replacement PC board.

NOTE: It is desirable to have a spare (known good) PC board available for PC board troubleshooting.

NOTE: Allow the machine to heat up so that all electrical components can reach their operating temperature.

5.Remove the replacement PC board and substitute it with the original PC board to recreate the original problem.

a.If the original problem does not reappear by substituting the original board, then the PC board was not the problem. Continue to look for bad connections in the control wiring harness, junction blocks, and terminal strips.

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ATTENTION

Static-Sensitive

Devices

Handle only at

Static-Safe

Workstations

-Remove your body’s static charge before opening the static- shielding bag. Wear an anti-static wrist strap. For safety, use a 1 Meg ohm resistive cord connected to a grounded part of the equipment frame.

-If you don’t have a wrist strap, touch an un-painted, grounded, part of the equipment frame. Keep touching the frame to prevent static build-up. Be sure not to touch any electrically live parts at the same time.

b. If the original problem is recreated by the substitution of the original board, then the PC board was the problem. Reinstall the replacement PC board and test the machine.

6.Always indicate that this procedure was followed when warranty reports are to be submitted.

NOTE: Following this procedure and writing on the warranty report, “INSTALLED AND SWITCHED PC BOARDS TO VERIFY PROBLEM,” will help avoid denial of legitimate PC board warranty claims.

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-Tools which come in contact with the PC board must be either conductive, anti-static or static-dissipative.

LN-8

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Contents LN-8 Semiautomatic Wire Feeder LN-8 SafetyElectric Shock can kill Iii Welding Sparks can cause fire or explosionSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Installation LN-8 with K303 Electrode DiameterLN-8 with K377 LN-8 with K378LN-8N and LN-8NE Power Source ConnectionsTable A.1 Work Lead Specifications LN-8S and LN-8SE and Converted LN-8N and LN-8NE Power Source Selection Switch Variable Voltage PC BoardTable A.2 LN-8 Power Source Connection Diagrams Power Source Connection DiagramsSection TOC Installation TOC Figure A.5 Connection of LN-8 to R3S-250 and R3S-325 9A-9Figure A.6 Connection of LN-8 to DC-600 10A-10Power Source To LN-8 Input Cable Plug Control Cable LN-8 for Same Polarity Operation Shock Can Kill LN-8 for Opposite Polarity Operation14A-14 Figure A.10 for Power Sources Other than Lincoln ElectricInput Cable Connections Cable Clamp Conductor Electrode Wire Reel BasecontrolLN-8N and LN-8S LN-8NE and LN-8SEExtension Tube Connector Connections to Wire FeederLocking ScrewSELF-TAPPING Screw Hinge Handle Figure A.14 Wire Feeder Handle InstallationGUN and Cable Assemblies Handling ProceduresLN-8S and LN-8SE Continuous Flux Feed Submerged ARC GeneralOperation Controls and Their Functions Safety InstructionsConstant Current Controls Gouging SparksCurrent Controls Voltage Constant Voltage ControlsAvoiding Ground Lead Protector GLP Activation Circuit ProtectionFigure B.3 Wire Feed Rolls and Guide Tube Installation Wire Feed Rolls and Guide TubesSetting for CV or CC Power Sources Welding with a Constant Voltage Power SourceSlots Coil Reel Mounting a 50 or 60 lb CoilAdapter Wire Reel Loading K1524-1 Universal Wire Reel StandK363-P READI-REEL Adapter 12 in./300 mm Diameter or 14 lb 6 kg To Mount 10 to 44 lb 4.5 to 20 kg SpoolsInnershield Coils READI-REELS a K438 READI-REEL Adapter Must be UsedBrass Blocks Hand Crank ARM Feeding Electrode to the LN-8N or LN-8SFeeding Electrode to the LN-8NE or LN-8SE with Extension Slow Acceleration Starting Code 7926 and Above Flux Tank LoadingAccessories General Table C.1 LN-8 Wire Feeder AccessoriesK163 Undercarriage Requires K303, K377, or K378 K161 Mechanized Travel Power PackK178 Mounting Platform K58 Magnetic SeparatorReel Mounting Accessories Constant Current Conversion Parts Welding Guns Welding GUN AccessoriesLN-8 Table of Contents Maintenance Section MaintenanceRoutine Maintenance Periodic Maintenance Theory of Operation Table of Contents Theory of Operation SectionGeneral Description Power Input CircuitsFigure E.2 GUN Trigger and 1CR Contact Control Circuits GUN Trigger and 1CR Relay Contact Control CircuitsFuse Field Applied Later CYCLE, the SCR Output Is Decreased SCR Operation5E-5 LN-8 Troubleshooting and Repair Return to Return to Section TOC HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Troubleshooting & RepairProblems Symptoms Troubleshooting GuideFunction Problems Transformer Test Perform the 1CR Relay Test Feeding Problems Welding Problems LN-8 Electrical Sequence of Operation Figure F.1 LN-8 Electrical Sequence of Operation Test Description Trigger Transformer TestTrigger Transformer Test Internal Voltage Test Receptacle ConnectorCircuit Applied Breaker Control BoardTable F.1 Voltage Test Points Internal Voltage Test1CR Relay Test 1CR Relay Test Table F.2 Relay Test Terminal Connections 1CR Relay TestDrive Motor Test Drive Motor Test 1CR Figure F.6 GUN Terminal Jumper LocationsTable F.3 Drive Motor Test Points To further check the drive motorPotentiometer Replacement Repair Procedure Circuit Breaker Replacement Retaining NUT Ground Lead Protector Switch Mount Flatwasher Lockwasher NUTGround Lead Protector Push Button Switch Replacement Ground Lead Protector Push Button Trigger Transformer Replacement Insulation Sheet Trigger Transformer NUT Relay PC Board Roundhead ScrewPC Board Replacement Control PC Board Variable Voltage PC Board Relay PC Board Figure F.10 PC Board LocationsRelay Board Removal Control PC Board Replacement Wire Drive Assembly and Component Replacement White BlackGreen Ground Yellow Blue TWO#568 #567 ShuntGearbox Insulation Sheet Mounting Plate MotorTOC Retest After Repair Electrical Diagrams LN-8N, -8NE, -8S, and -8SE Wiring Diagram Source Power to Work Connection Schematic1CR Wire Feed Motor Field Operating SchematicControl Board L5767 Schematic Variable Voltage Board L5039 Schematic Control Control Board L5767 LayoutVariable Voltage Board L5039 Layout SVM Error Reporting Form
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