Lincoln Electric SVM208-A service manual PC Board Troubleshooting Procedures

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TROUBLESHOOTING AND REPAIR

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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:

-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 prop- er 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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PC board can be damaged by static electricity.

b. If the original problem is recreated by the

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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.

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.

BULLDOG® 140

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Contents Bulldog California Proposition 65 Warnings SafetyCan be dangerous Electric Shock can kill ARC Rays can burnWelding and Cutting Sparks can cause fire or explosion Cylinder may explode if damagedIii Sûreté Pour Soudage a L’Arc Précautions DE SûretéSafety Methods of Reducing Emissions Mains Supply Master Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications Bulldog 140 K2708-1 InstallationEngine Exhaust can kill Safety PrecautionsLocation and Ventilation StoringOIL PRE-OPERATION Engine ServiceStacking TiltingElectrical Output CONNEC- Tions Welding Cable ConnectionsTable A.1 Recommended Welding Cable Size and Length Plugs and HAND-HELD Equipment Auxiliary Power ReceptaclesCable Installation Electrical ConnectionsCircuit Breakers Premises WiringBulldog Ation. do not RUN TheseTable of Contents Operation Section Operation Limitations WELDER/GENERATOR ControlsOutput Panel Controls Gasoline Engine Controls Engine OperationStarting the Engine Before Starting the EngineGenerator Operation Table B.1 Generator Power Applications Control Function / Operation Welding OperationLearning To Stick Weld Material Thickness Electrode Type Size SettingWelding Guidelines Stick WeldingWhat Happens in the Arc? Side view Correct Welding PositionButt Joints PracticeUse the following Do the followingPenetration Fillet JointsVertical-Down Welding Vertical-Up WeldingHardfacing To Reduce Wear How to Hardface the Sharp Edge Metal to Ground WearOverhead Welding Welding Sheet MetalCast Iron Plate Preparation Welding Cast IronHigh-Speed Group AWS E6013 Low Hydrogen Group AWS E7018Out-of-Position Group AWS E6011 Bulldog Table of Contents Accessories Section Accessories OPTIONS/ACCESSORIESLincoln Electric Accessories Table of Contents Maintenance Section Maintenance Routine and Periodic Maintenance Engine MaintenanceLocation Return to Section TOC To Section TOC Engine AdjustmentsTable D.1 Engine Maintenance Parts Spark Plug ServiceOperational Clearance Screws Brushes GENERATOR/WELDER MaintenanceFigure D.7. Major Component Locations Bulldog 1TABLE of CONTENTS-THEORY of Operation Section E-1 ENGINE, EXCITATION, Rotor Stator Theory of OperationFigure E.3 Rotor Field Feedback and Auxiliary Power Rotor Field Feedback Auxiliary PowerWeld Winding and Reactor Auxiliary Power Overcurrent Protection1TABLE of Contents Troubleshooting and Repair F-1 HOW to USE Troubleshooting Guide Troubleshooting and RepairPC Board Troubleshooting Procedures Output Problems Perform the Rotor Voltage Test Electric Authorized Field Ser vice FacilityProblems Symptoms Troubleshooting and Repair Perform Field Diode Test Engine Problems Troubleshooting and Repair Engine Throttle Adjustment Test Bulldog Rotor Voltage Test Test DescriptionMaterials Needed Procedure Rotor Voltage TestLead 200A Connection Ground Stud Field Diode Bridge Test + ~ Field Diode Bridge TestRotor Flashing Circuit Test Figure F.3 Brush Holder Leads 201- and 202B + Rotor Flashing Circuit TestMoving Parts can injure Bulldog Rotor Resistance Test Rotor Resistance Test Figure F.6 Brushes Retained with Cable TIE Cable TIE BrushesBulldog Engine Throttle Adjustment Test ROBIN/SUBARU Engine Frequency Counter Method Engine Throttle Adjustment TestROBIN/SUBARU Engine Strobe-tach MethodHigh Speed Stop Screw Scope Settings High Idle no Load Normal Open Circuit Voltage Waveform 115VAC SupplyTypical Weld Output Waveform Machine LoadedMachine Loaded to 125 Amps AT 23 VAC Brush Removal and Replacement Cable TIE Brushes Brush Removal and ReplacementReturn to Section Return to Section TOC Bulldog Rheostat Removal and Replacement Figure F.11 Rheostat Removal Rheostat Removal and ReplacementCapacitor AND/OR Diode Bridge Removal and Replacement Removal and Replacement Procedure Capacitor Removal and ReplacementCapacitor AND/OR Diode Bridge Figure F.13 Field Diode Bridge Location Procedure Field Diode Bridge Removal and ReplacementBulldog Instructions STATOR/ROTOR Removal and ReplacementGeneratorengine STATOR/ROTOR Removal and ReplacementFigure F.15 Generator Components Troubleshooting and Repair Figure F.16 Output Lead Location TIE Wrap Terminals Stator Removal ProcedureNuts Thru Bolts SupportReassembly Procedure Rotor Removal ProcedureFigure F.19 Checking ROTOR-STATOR AIR GAP WELDER/GENERATOR OUTPUT1 Auxiliary Power Receptacle OUTPUT1Retest After Repair Engine OutputBulldog Table of Contents Diagram Section Wiring Diagram Bulldog S28101
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