Lincoln Electric POWER MIG 255 SVM144-B Service Manual

Lincoln electric welder user manual
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RETURN TO MAIN MENU
SVM144-B
July, 2006

POWER MIG 255

For use with machines having Code Number : 10563, 10583,10986, 10990
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 READ-
ING THIS MANUAL AND THE
SAFETY PRECAUTIONS CON-
TAINED THROUGHOUT. And,
most importantly, think before
you act and be careful.

SERVICE MANUAL

Copyright © 2006 Lincoln Global Inc.
• 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

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Summary of Contents for Lincoln Electric POWER MIG 255 SVM144-B

  • Page 1: Power Mig

    RETURN TO MAIN MENU SVM144-B July, 2006 POWER MIG 255 For use with machines having Code Number : 10563, 10583,10986, 10990 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 .
  • Page 2: Safety

    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.
  • Page 3: Electric Shock Can Kill

    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.
  • Page 4 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. Remember that welding sparks and hot materials from welding can easily go through small cracks and openings to adjacent areas.
  • Page 5 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 suiv- antes: Sûreté Pour Soudage A L’Arc 1. Protegez-vous contre la secousse électrique: a.
  • Page 6: Table Of Contents

    RETURN TO MAIN MENU MASTER TABLE OF CONTENTS FOR ALL SECTIONS Safety ............i-iv Installation .
  • Page 7 Section A-1 TABLE OF CONTENTS Section A-1 - INSTALLATION SECTION - Installation ...Section A Technical Specifications...A-2 Safety Precautions ...A-3 Uncrating the POWER MIG 255...A-3 Location...A-3 Input Power, Grounding and Connection Diagrams ...A-3 Output Polarity Connections...A-5 Gun and Cable Installation...A-6 Shielding Gas ...A-6...
  • Page 8: Installation

    TECHNICAL SPECIFICATIONS – POWER MIG 255 Standard Voltage/Frequency Input Current @ 200 Amp Rated Output Input Current @ 250 Amp Rated Output 208/230/60 Hz 230/460/575/60 Hz Duty Cycle 100% Welding Current Range (Continuous) 30 – 300 Amps RECOMMENDED INPUT WIRE AND FUSE SIZES Input Voltage/ Fuse or Breaker Frequency (Hz)
  • Page 9: Safety Precautions

    Roll the machine off the skid assembly. LOCATION Locate the welder in a dry location where there is free circulation of clean air into the louvers in the back and out the front. A location that minimizes the amount of...
  • Page 10 The center contact in the receptacle is for the grounding connection. A green wire in the input cable connects this contact to the frame of the welder. This ensures proper grounding of the welder frame when the welder plug is inserted into the receptacle. POWER MIG 255...
  • Page 11: Output Polarity Connections

    PHASE OF A TWO OR THREE PHASE SYSTEM. INSTALLATION OUTPUT POLARITY CONNECTIONS The welder, as shipped from the factory, is connected for electrode positive (+) polarity. This is the normal polarity for GMA welding. If negative (–) polarity is required, interchange the con- nection of the two cables located in the wire drive com- partment near the front panel.
  • Page 12: Gun And Cable Installation

    0.035-0.045 in. (0.9-1.2 mm) electrode and an 0.035 in. (0.9 mm) contact tip. Install the 0.045 tip (also pro- vided) if this wire size is being used. WARNING Turn the welder power switch off before installing gun and cable. ------------------------------------------------------------------------ 1. Lay the cable out straight.
  • Page 13: Operation Section

    (Using the Molded Plastic K363-P Readi-Reel Adapter)...B-5 To Mount 10 to 44 lb (4.5-20 kg) Spools (12 in./300 mm Diameter) or 14 lb (6 kg) Innershield Coils ...B-5 To Start the Welder...B-6 Feeding Wire Electrode ...B-6 Idle Roll Pressure Setting ...B-6 Setting Run-In Speed on Standard Power MIG Feeder ...B-6...
  • Page 14 Read entire Operation section before operating the POWER MIG 255. Observe all safety information throughout this manual. OPERATION WARNING ELECTRIC SHOCK can kill. • Do not touch electrically live parts or electrode with skin or wet clothing. Insulate yourself from work and ground.
  • Page 15: Operation

    PRODUCT DESCRIPTION The POWER MIG™ 255 is a complete semiautomatic constant voltage DC arc welding machine built to meet NEMA specifications. It combines a constant voltage power source and a constant speed wire feeder with a microcomputer-based controller to form a reliable high- performance welding system.
  • Page 16: Description Of Controls

    DESCRIPTION OF CONTROLS Power ON/OFF Switch — Place the lever in the “ON” position to energize the POWER MIG 255. When the power is on, the red LED display lights illuminate. Voltage Control — This is a continuous control that gives full range adjustment of power source output volt- age.
  • Page 17: Procedure For Changing Drive And Idle Roll Sets

    PROCEDURE FOR CHANGING DRIVE AND IDLE ROLL SETS 1. Turn off the power source. 2. Release the pressure on the idle roll by swinging the adjustable pressure arm down toward the back of the machine. Lift the cast idle roll assem- bly and allow it to sit in an upright position.
  • Page 18: To Start The Welder

    Turn the Power Switch switch to ON. This lights the red LED display lights. With the desired voltage and wire speed selected, operate the gun trigger for welder out- put and to energize the wire feed motor. FEEDING WIRE ELECTRODE...
  • Page 19: Making A Weld

    NOTE: Arc starting characteristics may be effected when using the fast run-in mode since optimum start- ing processes are being overridden. On the initial trigger closure at power up, no output power or wire feed will be available until the trigger is opened and reclosed, regardless of wire feed speed dial setting.
  • Page 20: Fan Control

    The POWER MIG 255 has built-in protective ther- mostats that respond to excessive temperature. They open the wire feed and welder output circuits if the machine exceeds the maximum safe operating tem- perature because of a frequent overload, or high ambi- ent temperature plus overload.
  • Page 21 Section C-1 - ACCESSORIES SECTION - Accessories ...Section C Drive Roll Kits ...C-2 3/64 in. (1.2 mm) Aluminum Feeding Kit (K1703-1) ...C-2 K363P Readi-Reel Adapter ...C-2 Dual Cylinder Mounting Kit (K1702-1)...C-2 Alternative Magnum GMAW Gun and Cable Assemblies ...C-2 Magnum Gun Connection Kit (Optional K466-6) ...C-2 Timer Kit Installation (Optional K1701-1) ...C-2 Operating Instructions for Timer Kit...C-3 Spool Gun Adapter Kit (K1700-1) (Included in the K1692-1)...C-4...
  • Page 22: Accessories

    DRIVE ROLL KITS Refer to Table C.1 for various drive roll kits that are available for the POWER MIG. All items in Bold are supplied standard with the POWER MIG. TABLE C.1 — AVAILABLE DRIVE ROLL KITS. Wire Size 0.023-0.030 in. (0.6-0.8 mm) KP1696-030S Solid 0.035 in.
  • Page 23 3. Using a screwdriver, remove the two screws securing the lower cover panel to the front of the machine. Remove the lower cover panel. 4. Attach the rectangular 10-pin plug connector on the timer kit wiring harness to the mating recepta- cle connector located directly behind the removed cover panel.
  • Page 24 The Spool Gun Adapter Kit provides direct connection and use of the Spool Gun (with remote speed control) with the POWER MIG 255 wire feed welder. It also provides gun trigger switch transfer between the machine’s use with its feeder gun or the spool gun for same polarity welding with different wire and gas processes.
  • Page 25 Section D-1 TABLE OF CONTENTS Section D-1 - MAINTENANCE SECTION - Maintenance ...Section D Safety Precautions ...D-2 Routine and Periodic Maintenance ...D-2 Drive Rolls and Guide Tubes ...D-2 Cable Cleaning ...D-2 Gun Tubes and Nozzles ...D-2 Contact Tip and Gas Nozzle Installation...D-4 Liner Removal and Replacement ...D-4 Liner Removal, Installation, and Trimming Instructions for Magnum 250L ...D-4 Gun Handle Disassembly ...D-5...
  • Page 26: Maintenance

    SAFETY PRECAUTIONS WARNING • Have a qualified electrician do the maintenance and troubleshooting work. • Disconnect the input power off using the dis- connect switch at the main input supply before working inside machine. • Unplug the power cable if it is connected to a receptacle.
  • Page 27 MAINTENANCE FIGURE D.1 — COMPONENT LOCATIONS. MOTOR ASSEMBLY CONTROL PC BOARD SNUBBER PC BOARD WIRE DRIVE ASSEMBLY RECTIFIER BRIDGE OUTPUT CHOKE CAPACITOR BANK MAIN TRANSFORMER POWER ENHANCEMENT CHOKE POWER MIG 255...
  • Page 28: Contact Tip And Gas Nozzle Installation

    CONTACT TIP AND GAS NOZZLE INSTALLATION 1. Choose the correct size contact tip for the elec- trode being used (wire size is stenciled on the side of the contact tip) and screw it snugly into the gas diffuser. a. Be sure the nozzle insulator is fully screwed onto the gun tube and does not block the gas holes in the diffuser.
  • Page 29: Gun Handle Disassembly

    9. Tighten the setscrew on the brass cable connector. NOTE: Do not install the gas diffuser onto the end of the gun tube at this time. 10. Straighten the cable with the gas nozzle and noz- zle insulator removed from the gun tube. 11.
  • Page 30: Accessories And Expendable Replacement Parts For Magnum 250L Gun And Cable Assemblies

    ACCESSORIES AND EXPENDABLE REPLACEMENT PARTS FOR MAGNUM 250L GUN AND CABLE ASSEMBLIES DESCRIPTION Cable Liner For 15 ft (4.5 m) or Shorter Cable Contact Tips Standard Duty Heavy Duty Tapered Tab (For Aluminum) Gas Nozzles Fixed (Flush) (Recessed) (Requires: Gas Diffuser Assembly) Adjustable Slip-On (Requires: Nozzle Insulator Assembly) (Requires: Gas Diffuser Assembly)
  • Page 31 Section E-1 - THEORY OF OPERATION SECTION - Theory of Operation ...Section E Input Line Voltage and Main Transformer...E-2 Output Rectification and Feedback Control...E-3 Constant Voltage Output ...E-4 Wire Drive Motor and Feedback...E-5 Thermal and Overload Protection...E-6 Overcurrent Protection ...E-6 Wire Feed Overload Protection ...E-6 SCR Operation...E-7 FIGURE E.1 –...
  • Page 32: Theory Of Operation

    THEORY OF OPERATION FIGURE E.2 — INPUT LINE VOLTAGE AND MAIN TRANSFORMER. WIRE SPEED VOLTAGE 115 VAC 30 VAC LINE SWITCH RECONNECT MAIN TRANSFORMER INPUT LINE VOLTAGE AND MAIN TRANSFORMER The desired single phase input power is connected to the POWER MIG 255 through a line switch located on the front panel.
  • Page 33: Output Rectification And Feedback Control

    THEORY OF OPERATION FIGURE E.3 — OUTPUT RECTIFICATION AND FEEDBACK. WIRE SPEED VOLTAGE 115 VAC 30 VAC LINE SWITCH RECONNECT MAIN TRANSFORMER OUTPUT RECTIFICATION AND FEEDBACK CONTROL The AC output from the main transformer secondary weld winding is rectified and controlled through the SCR rectifier assembly.
  • Page 34: Constant Voltage Output

    THEORY OF OPERATION FIGURE E.4 — CONSTANT VOLTAGE OUTPUT. WIRE SPEED VOLTAGE 115 VAC 30 VAC LINE SWITCH RECONNECT MAIN TRANSFORMER CONSTANT VOLTAGE OUTPUT The controlled DC output from the SCR rectifier assembly is supplied to the power factor enhancement choke which limits the rate at which the supply current rises through the capacitors.
  • Page 35: Wire Drive Motor And Feedback

    THEORY OF OPERATION FIGURE E.5 — WIRE DRIVE MOTOR AND FEEDBACK. WIRE SPEED VOLTAGE 115 VAC 30 VAC LINE SWITCH RECONNECT MAIN TRANSFORMER WIRE DRIVE MOTOR AND FEEDBACK The wire drive motor is controlled by the control board. A motor speed feedback signal is generated at the motor tach and sent to the control board.
  • Page 36: Thermal And Overload Protection

    The other thermostat is located on the SCR heat sink assembly. They open the wire feed and welder output circuits if the machine exceeds the maximum safe operating temperature. This can be caused by a frequent overload, or high ambient temperature.
  • Page 37: Scr Operation

    THEORY OF OPERATION INPUT CATHODE OUTPUT ANODE GATE SCR OPERATION A silicon controlled rectifier (SCR) is a three terminal device used to control rather large currents to a load. An SCR acts very much like a switch. See Figure E.6 for a graphical representation of SCR operation.
  • Page 38 NOTES POWER MIG 255...
  • Page 39 Section F-1 - TROUBLESHOOTING & REPAIR SECTION - Troubleshooting & Repair Section ...Section F How to Use Troubleshooting Guide...F-2 PC Board Troubleshooting Procedures and Replacement...F-3 Troubleshooting Guide ...F-4 Test Procedures Main Transformer Test ...F-11 Rectifier Diode Bridge Test...F-15 Static SCR Rectifier Assembly Test ...F-19 Active SCR Rectifier Assembly Test...F-23 Wire Drive Motor and Tachometer Feedback Test...F-27 Oscilloscope Waveforms...
  • Page 40: Troubleshooting & Repair Section

    If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877. CAUTION Step 3. PERFORM COMPONENT TESTS. The last column, labeled “Recommended Course of...
  • Page 41: Pc Board Troubleshooting Procedures

    - 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.
  • Page 42: Troubleshooting Guide

    If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 43 200 amps at 28 volts. If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 44 If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877. detailed in the beginning of this manual.
  • Page 45 If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877. detailed in the beginning of this manual.
  • Page 46 If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877. detailed in the beginning of this manual.
  • Page 47 If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877. detailed in the beginning of this manual.
  • Page 48 The arc striking is poor. If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 49: Main Transformer Test

    If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 50 F-12 TROUBLESHOOTING & REPAIR MAIN TRANSFORMER TEST (continued) FIGURE F.1 — G3521 CONTROL PC BOARD AND M19248 SNUBBER PC BOARD MAIN TRANSFORMER TEST POINTS. TEST PROCEDURE WARNING The ON/OFF POWER SWITCH will be “hot” during these tests. ---------------------------------------------------------- NOTE: Secondary voltages will vary pro- portionately with the primary input voltage.
  • Page 51 F-13 TROUBLESHOOTING & REPAIR MAIN TRANSFORMER TEST (continued) 6. Connect main input power to the machine. 7. Turn the POWER MIG 255 ON/OFF POWER SWITCH to ON. 8. Carefully make the following voltage tests at plug J6. a. Turn the machine OFF between each test.
  • Page 52 F-14 TROUBLESHOOTING AND REPAIR MAIN TRANSFORMER TEST (continued) 14. Locate the following leads on plug J9 on the M19248 snubber PC board and on plug J5 on the G3521 control PC board. See Figure F.1. G3521: LEAD M19248: LEAD 208S 209S 15.
  • Page 53: Rectifier Diode Bridge Test

    RECTIFIER DIODE BRIDGE TEST WARNING Service and repair should only be performed by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in dan- ger to the technician or machine operator and will invalidate your factory war- ranty.
  • Page 54 F-16 TROUBLESHOOTING & REPAIR RECTIFIER DIODE BRIDGE TESTING (continued) FIGURE F.2 — G3521 RECTIFIER DIODE BRIDGE LOCATION. RECTIFIER DIODE BRIDGE (D2) TEST PROCEDURE 1. Disconnect the main AC input power to the machine. 2. Remove the case top and side panels with a 3/8 in.
  • Page 55 F-17 TROUBLESHOOTING & REPAIR RECTIFIER DIODE BRIDGE TESTING (continued) 6. Turn the POWER MIG 255 ON/OFF POWER SWITCH to ON. 7. Carefully make the following voltage tests: a. Turn the machine OFF between each test. b. Carefully connect the meter plugs to the exposed lead connections.
  • Page 56 F-18 NOTES F-18 POWER MIG 255...
  • Page 57: Static Scr Rectifier Assembly Test

    STATIC SCR RECTIFIER ASSEMBLY TEST WARNING Service and repair should only be performed by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in dan- ger to the technician or machine operator and will invalidate your factory war- ranty.
  • Page 58 F-20 TROUBLESHOOTING & REPAIR STATIC SCR RECTIFIER ASSEMBLY TEST (continued) FIGURE F.3 — REMOVE PLUGS J6 AND J9 TO PERFORM STATIC RECTIFIER ASSEMBLY TEST. TEST PROCEDURE 1. Disconnect main AC input power to the machine. 2. Remove the case top and side panels with a 3/8 in.
  • Page 59: Active Scr Rectifier Assembly Test

    F-21 TROUBLESHOOTING & REPAIR STATIC SCR RECTIFIER ASSEMBLY TEST (continued) FIGURE F.4 — LOCATION OF LEADS X2 AND X3. NEGATIVE CAPACITOR BANK BUSS 6. Disconnect leads X2 and X3 (braided copper strap) from the negative capaci- tor bank buss bar using a 1/2 in. open end wrench.
  • Page 60 F-22 NOTES F-22 POWER MIG 255...
  • Page 61 ACTIVE SCR RECTIFIER ASSEMBLY TEST WARNING Service and repair should only be performed by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in dan- ger to the technician or machine operator and will invalidate your factory war- ranty.
  • Page 62 F-24 TROUBLESHOOTING & REPAIR ACTIVE SCR RECTIFIER ASSEMBLY TEST (continued) FIGURE F.6 — CONTROL BOARD MOLEX PLUG LOCATIONS FOR G3521 PC CONTROL BOARD. TEST PROCEDURE 1. Disconnect main AC input power to the machine. 2. Remove the case top and side panels with a 3/8 in.
  • Page 63 F-25 TROUBLESHOOTING & REPAIR ACTIVE SCR RECTIFIER ASSEMBLY TEST (continued) 6. Disconnect leads X2 and X3 (braided copper strap) from the negative capaci- tor bank buss bar using a 1/2 in. open end wrench. See Figure F.7. FIGURE F.7 — LOCATION OF LEADS X2 AND X3.
  • Page 64 F-26 TROUBLESHOOTING & REPAIR ACTIVE SCR RECTIFIER ASSEMBLY TEST (continued) 9. Connect the tester to the SCR 1 as shown in Figure F.8. a. Connect tester lead (A) to the anode. b. Connect tester lead (C) to the cathode. c. Connect tester lead (G) to the gate. 10.
  • Page 65: Wire Drive Motor And Tachometer Feedback Test

    WIRE DRIVE MOTOR AND TACHOMETER FEEDBACK TEST WARNING Service and repair should only be performed by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in dan- ger to the technician or machine operator and will invalidate your factory war- ranty.
  • Page 66 F-28 TROUBLESHOOTING & REPAIR WIRE DRIVE MOTOR AND TACHOMETER FEEDBACK TEST (continued) FIGURE F.9 — PLUG J1 LOCATION ON G3521 PC CONTROL BOARD. TEST PROCEDURE NOTE: POLARITY MUST BE OBSERVED FOR THESE TESTS. Test for Correct Wire Drive Motor Armature Voltage 1.
  • Page 67 F-29 TROUBLESHOOTING & REPAIR WIRE DRIVE MOTOR AND TACHOMETER FEEDBACK TEST (continued) 6. Make the following voltage tests: a. Turn the machine OFF between each test. b. Carefully insert the meter probes into the back of each Molex plug pin cavity to perform the test. c.
  • Page 68 F-30 TROUBLESHOOTING & REPAIR WIRE DRIVE MOTOR AND TACHOMETER FEEDBACK TEST (continued) TEST FOR FEEDBACK VOLTAGE TO CONTROL BOARD 1. Disconnect the main AC input power to the machine. 2. Locate plug J1 on the G3521 control PC board. 3. Locate the following leads on plug J1 (see Figure F.9): LEAD 206B...
  • Page 69: Normal Open Circuit Voltage Waveform

    F-31 TROUBLESHOOTING & REPAIR NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM 20.0 V This is a typical DC output voltage waveform generated from a properly operating machine. Note that each vertical division represents 20 volts and that each horizontal division represents 2.5 milliseconds in time. NOTE: Scope probes connected at machine output terminals: (+) probe to elec-...
  • Page 70: Typical Output Voltage Waveform - Machine Loaded

    F-32 TROUBLESHOOTING & REPAIR TYPICAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADED 20.0 V MACHINE LOADED TO 250 AMPS AT 26 VDC This is a typical DC output voltage waveform generated from a properly operating machine. Note that each vertical division represents 20 volts and that each horizontal division represents 5 milliseconds in time.
  • Page 71: Abnormal Output Voltage Waveform - Machine Loaded One Output Scr Not Functioning

    F-33 TROUBLESHOOTING & REPAIR ABNORMAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADED ONE OUTPUT SCR NOT FUNCTIONING 20.0 V MACHINE LOADED TO 220 AMPS AT 22 VDC This is NOT a typical DC output voltage waveform. One output SCR is not function- ing.
  • Page 72: Abnormal Open Circuit Voltage Output Capacitor Bank Not Functioning

    F-34 TROUBLESHOOTING & REPAIR ABNORMAL OPEN CIRCUIT VOLTAGE OUTPUT CAPACITOR BANK NOT FUNCTIONING 20.0 V This is NOT the typical DC output voltage waveform. The output capacitors are not functioning. Note the lack of “filtering” in the output waveform. The output capacitor bank was disconnected.
  • Page 73: Typical Scr Gate Voltage Waveform

    F-35 TROUBLESHOOTING & REPAIR TYPICAL SCR GATE VOLTAGE WAVEFORM 2.00 V This is a typical SCR gate pulse voltage waveform. The machine was in an open circuit condition (no load) and operating properly. Note that each vertical division represents 2 volts and each horizontal division represents 5 milliseconds in time.
  • Page 74 F-36 NOTES F-36 POWER MIG 255...
  • Page 75: Control Pc Board Removal And Replacement

    If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 76 F-38 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (Continued) FIGURE F.10 — WIRING HARNESS AND MOLEX PLUG LOCATIONS. CONTROL PC BOARD REMOVAL AND REPLACEMENT PROCEDURE 1. Disconnect main input power the machine. 2. Open the side panels and remove the tool tray using a 5/16 in.
  • Page 77: Troubleshooting And Repair

    F-39 TROUBLESHOOTING AND REPAIR REMOVAL AND REPLACEMENT PROCEDURE (Continued) FIGURE F.11 — CONTROL BOARD MOUNTING. MOUNTING PC CONTROL STANDOFF BOARD NOTE: TOP COVER SHOWN REMOVED FOR CLARITY. 4. Ensure a static electricity grounding strap is used before handling the con- trol PC boards.
  • Page 78 F-40 NOTES F-40 POWER MIG 255...
  • Page 79 If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 80: Wire Drive Assembly Removal And Replacement

    F-42 TROUBLESHOOTING & REPAIR WIRE DRIVE ASSEMBLY REMOVAL AND REPLACEMENT (continued) FIGURE F.12 — WIRE DRIVE ASSEMBLY REMOVAL FOR CODES 10563 & 10583 REFER TO P344-F.2 FOR EXPLODED VIEW OF WIRE DRIVE FOR CODES 10986 AND 10990 - SIMILAR PROCEDURE 1.
  • Page 81 F-43 TROUBLESHOOTING & REPAIR WIRE DRIVE ASSEMBLY REMOVAL AND REPLACEMENT (continued) 10. Rotate the adjustment arm assembly counterclockwise to release the tension on the idle arm. 11. Swing the idle arm up and away from the wire drive assembly. 12. Use a screwdriver and remove the round head screw, lock washer, and flat washer securing the molded drive roll shaft assembly to the wire drive assem-...
  • Page 82 F-44 NOTES F-44 POWER MIG 255...
  • Page 83 If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 84: Scr Output Rectifier Removal And Replacement

    F-46 TROUBLESHOOTING & REPAIR SCR OUTPUT RECTIFIER REMOVAL AND REPLACEMENT (continued) PROCEDURE 1. Remove the case side panels using a 3/8 in. nutdriver. 2. Disconnect lead #208S and trans- former lead X1 from the heat sink on the left side of the machine using a 1/2 in.
  • Page 85 F-47 TROUBLESHOOTING & REPAIR SCR OUTPUT RECTIFIER REMOVAL AND REPLACEMENT (continued) FIGURE F.15 — RIGHT HEAT SINK LEAD DISCONNECTION. ASSEMBLY LEAD #320 LEAD #209S LEAD 5. Remove lead #209S and transformer lead X4 from the right side heat sink using a 1/2 in. socket wrench and 1/2 in.
  • Page 86 F-48 NOTES F-48 POWER MIG 255...
  • Page 87 If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 88: Capacitor Bank Removal And Replacement

    F-50 TROUBLESHOOTING & REPAIR CAPACITOR BANK REMOVAL AND REPLACEMENT (continued) FIGURE F.16 — LOCATION OF CAPACITOR BANK REMOVAL AND REPLACEMENT COMPONENTS. SCR DIODE LEAD SHUNT X1 AND X2 PROCEDURE See Figure F.16 for location of capacitor bank removal and replacement components. 1.
  • Page 89 If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 90: Main Transformer And Output Choke Removal And Replacement

    F-52 TROUBLESHOOTING & REPAIR MAIN TRANSFORMER AND OUTPUT CHOKE REMOVAL AND REPLACEMENT (continued) FIGURE F.17 — MAIN TRANSFORMER REMOVAL. LEAD OUTPUT CHOKE POSITIVE LEAD MAIN TRANSFORMER PROCEDURE 1. Disconnect main input power to the machine. 2. Remove the case side panels using a 3/8 in.
  • Page 91 F-53 TROUBLESHOOTING & REPAIR MAIN TRANSFORMER AND OUTPUT CHOKE REMOVAL AND REPLACEMENT (continued) 11. Unplug and label leads X5, X6, X7, X8, and X9. These leads have connectors near the trans- former which can be disconnected. 12. Disconnect the output choke lead from the posi- tive capacitor bank buss using two 1/2 in.
  • Page 92 F-54 NOTES F-54 POWER MIG 255...
  • Page 93 If for any reason you do not understand the test procedures or are unable to per- form the test / repairs safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
  • Page 94 F-56 TROUBLESHOOTING & REPAIR FAN MOTOR ASSEMBLY REMOVAL AND REPLACEMENT (continued) FIGURE F.18 — FAN MOTOR ASSEMBLY REMOVAL. LEAD #353 LEAD #352 PROCEDURE 1. Disconnect main input power to the machine. 1. Remove the case side panels using a 3/8 in. nutdriver. 2.
  • Page 95: Retest After Repair

    F-57 TROUBLESHOOTING AND REPAIR F-57 RETEST AFTER REPAIR INPUT IDLE AMPS AND WATTS Input Volts/Hertz Maximum Idle Amps Maximum Idle Watts 230/60 OPEN CIRCUIT VOLTAGE 35-40 VDC WIRE SPEED RANGE 50 - 700 IPM (1.27 - 17.8 m/minute) POWER MIG 255...
  • Page 96 F-58 NOTES F-58 POWER MIG 255...
  • Page 97 Section G-1 TABLE OF CONTENTS Section G-1 - ELECTRICAL DIAGRAMS SECTION - Electrical Diagrams ...Section G Wiring Diagram - Entire Machine - Code 10563 - (L10979) ....G-2 Wiring Diagram - Entire Machine - Code 10583 - (L10980) .
  • Page 98 WIRING DIAGRAM - ENTIRE MACHINE - CODE 10563 - (L10979) CAVITY NUMBERING SEQUENCE (COMPONENT SIDE OF P.C. BOARD) TRIGGER TO SINGLE PHASE SUPPLY LINE 230V 208V RECONNECT PANEL LINE SWITCH TO GROUND PER NATIONAL ELECTRICAL CODE NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine. ELECTRICAL DIAGRAMS POWER MIG 255 (208/230V) NOTES:...
  • Page 99: Electrical Diagrams

    WIRING DIAGRAM - ENTIRE MACHINE - CODE 10583 - (L10980) CAVITY NUMBERING SEQUENCE (COMPONENT SIDE OF P.C. BOARD) TRIGGER RECONNECT PANEL LINE (SHOWN CONNECTED SWITCH FOR 230V) TO SINGLE PHASE SUPPLY LINE TO GROUND PER NATIONAL ELECTRICAL CODE NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine. ELECTRICAL DIAGRAMS POWER MIG 255 (230/460/575V) NOTES:...
  • Page 100: Wiring Diagram - Entire Machine - Code 10986 - (L11980

    WIRING DIAGRAM - ENTIRE MACHINE - CODE 10986 - (L11980) CAVITY NUMBERING SEQUENCE (COMPONENT SIDE OF P.C. BO ARD) TRIGGER RECONNECT PANEL LINE POWER POWER POWER (SHOWN CONNECTED SWITCH FOR 230V) TRANSFORMER TRANSFORMER TRANSFORMER TO SINGLE PHASE SUPPLY LINE TO GROUND PER NATIONAL ELECTRICAL CODE NOTE: This diagram is for reference only.
  • Page 101: Wiring Diagram - Entire Machine - Code 10990 - (L11979

    WIRING DIAGRAM - ENTIRE MACHINE - CODE 10990 - (L11979) ELECTRICAL SYMBOLS PER E1537 CAVITY NUMBERING SEQUENCE (COMPONENT SIDE OF P.C. BO ARD) INDICATES CONNECTOR CAVITY NO. NUMBERING SEQUENCE (NON-LEAD SIDE OF CONNEC TOR) TRIGGER SECONDARY VOLTAGES SHOWN ARE NO LOAD RMS VALUES TO SINGLE PHASE SUPPLY LINE 230V...
  • Page 102: Control Pc Board Schematic (G3520-1D1

    Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 103: Control Pc Board Assembly (G3521-1

    Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 104: Display Pc Board Schematic (L10951

    Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 105 Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 106 Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 107 Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is provided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician.
  • Page 108 Your Company__________________________ Your Name_____________________________ Please give detailed description below: ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ SD287 04/06 Thank You, Technical Services Group Lincoln Electric Co. 22801 St. Clair Ave. Cleveland, Ohio 44117-1199 FAX 216-481-2309...

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