Lincoln Electric SVM170-A service manual PC Board Troubleshooting Procedures

Page 43

TOC

F-3

F-3

TROUBLESHOOTING & REPAIR

PC BOARD TROUBLESHOOTING PROCEDURES

Return to Section

Return to Section TOC

TOC

Return to Master

Return to Master TOC

TOC

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 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.

Return to Section

TOC

Return to Master

TOC

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.

Return to Section

Return to Master

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

POWER MIG 255C

Image 43
Contents Power MIG 255C California Proposition 65 Warnings 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 Table of Contents Installation Section InstallationTechnical Specifications Power MIG 255C Location Safety PrecautionsUncrating the Power MIG 255C Input POWER, Grounding and Connection DiagramsInstallation Figure A.2 Triple Voltage Machine Input Connections Auxiliary Power Receptacles GUN and Cable InstallationShielding GAS Operation Table of Contents Operation SectionWear eye, ear and body protec- tion OPERATIONB-2Limitations Product DescriptionRecommended Processes and Equipment Welding CapabilityWire Drive Roll Wire Size Conversion PartsDescription of Controls Wire Reel Loading Readi REELS, Spools or Coils Procedure for ChangingDrive and Idle Roll Sets To Start the Welder Feeding Wire ElectrodeIdle Roll Pressure Setting Wire Drive ConfigurationFigure B.4 Making a Weld When Timer Option is not installedInstructions to Enter Slow RUN-IN Instructions to Enter Fast RUN-INInput Line Voltage Protection Avoiding Wire Feeding ProblemsWire Feed Overload Protection FAN ControlOvercurrent Protection Welding Thermal Overload ProtectionTable of Contents Accessories Section AccessoriesDual Cylinder Mounting KIT K1702-1 Drive Roll KitsMagnum GUN Connection KIT K363P READI-REEL AdapterSpool GUN Operating Instructions for Timer KITConnecting the Spool GUN to the Power MIG 255C K1738-1 Spool Gun Hanger AccessoryMaking a Weld with the Magnum SG Spool GUN Making a Weld with the Prince XL Spool GUNSG Spool Gun Wire Feed Speed Power MIG Table of Contents Maintenance Section MaintenanceLiner Removal and Replacement GUN Tubes and Nozzles General MaintenanceGUN Cable Cleaning Contact TIP and GAS Nozzle InstallationTable D.1 GUN Handle DisassemblyEnglish Metric Description MAINTENANCED-4Theory of Operation Table of Contents Theory of Operation SectionMain Transformer Input Line VoltageFeedback Control Output RectificationFigure E.4 Constant Voltage Output Constant Voltage OutputFeedback Wire Drive MotorThermal and Overload Protection Wire Feed Overload ProtectionFigure E.6 SCR Operation SCR OperationPower MIG 255C Table of Contents Troubleshooting and Repair Section Troubleshooting and RepairHOW to USE Troubleshooting Guide 2TROUBLESHOOTING and REPAIRF-2PC Board Troubleshooting Procedures Output Problems Troubleshooting GuideToxic. Avoid contact with any Problems Possible AreasSymptoms Misadjustments Course of Action Trolyte in these capacitors isPerform the SCR Rectifier Function Problems Wire Feeding Problems Welding Problems Welding Problems Materials Needed Test ProceduresMain Transformer Test Test DescriptionON/OFF Power Switch will be hot during these tests Test Procedure16J5 8J5 115VAC206 3J5 Rectifier Diode Bridge Test Figure F.2 G3521 Rectifier Diode Bridge Location 16TROUBLESHOOTING and REPAIRF-16354 206 36 VDC 208 206 28 VAC 209Power MIG 255C Static SCR Rectifier Assembly Test Static SCR Rectifier Assembly Test Active SCR Rectifier Assembly Test Power MIG 255C Active SCR Rectifier Assembly Test Active SCR Rectifier Assembly Test Figure F.7 Location Leads X2 Figure F.8 Wire Drive Motor and Tachometer Feedback Test 4J1 Wire Drive Motor and Tachometer Feedback Test515B 206B 15 VDC 5J1 1J1 Test for Supply Voltage to Tachometer555 206B To 3.5 VDC 6J1 1J1 Test for Feedback Voltage to Control BoardVolts Normal Open Circuit Voltage WaveformTypical Output Voltage Waveform Machine Loaded Machine Loaded to 250 Amps AT 26 VDC Scope SettingsMachine Loaded to 220 Amps AT 22 VDC Scope Settings Troubleshooting and Repair Typical SCR Gate Voltage Waveform Power MIG 255C Control PC Board Removal and Replacement Component Replacement ProceduresDescription Procedure Removal and ReplacementFigure F.11 Control Board Mounting Power MIG 255C Wire Drive Assembly Removal and Replacement Wire Drive Assembly Removal and Replacement Procedure Power MIG 255C SCR Output Rectifier Removal and Replacement SCR Output Rectifier Removal and Replacement Figure F.15 Right Heat Sink Lead Disconnection Power MIG 255C Capacitor Bank Removal and Replacement Capacitor Bank Removal and Replacement Main Transformer and Output Choke Removal and Replacement Main Transformer and Output Choke 52TROUBLESHOOTING and REPAIRF-52TOC Power MIG 255C FAN Motor Assembly Removal and Replacement FAN Motor Assembly Removal and Replacement Input Volts/Hertz Wire Speed RangeRetest After Repair Open Circuit VoltagePower MIG 255C Section G-1 Electrical Diagrams SectionWiring Diagram Entire Machine Code 11192 L12464 Electrical DiagramsWiring Diagram Entire Machine Code 11218 L12506 Schematic Entire Machine G4752 Schematic Control PC Board G4823-2D1 Sheet Electrical Diagrams Electrical Diagrams Item Used with QTY Part Number Description PC Board Assembly Control G4824-2D1Powermig Schematic Display PC Board L10951Lincoln Electric CO PC Board Assembly Display L10952SVM Error Reporting Form