Lincoln Electric SQUARE WAVE TIG 355 Service Manual
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Lincoln Electric SQUARE WAVE TIG 355 Service Manual

Lincoln Electric SQUARE WAVE TIG 355 Service Manual

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SQUARE WAVE TIG 355
For use with machines having Code Numbers:
9951, 9952, 9953, 9954, 9955, 10056, 10057,
10058, 10059, 10060, 10299, 10389, 10390
SERVICE MANUAL
SVM118-B
| Issue D ate 12, Apr
© Lincoln Global, Inc. All Rights Reserved.
NOTE: This manual will cover most of the troubleshooting and repair
procedures for the code numbers listed. Some variances may exist when
troubleshooting/repairing later code numbers.
®

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Summary of Contents for Lincoln Electric SQUARE WAVE TIG 355

  • Page 1 NOTE: This manual will cover most of the troubleshooting and repair procedures for the code numbers listed. Some variances may exist when troubleshooting/repairing later code numbers. SQUARE WAVE TIG 355 ® For use with machines having Code Numbers: 9951, 9952, 9953, 9954, 9955, 10056, 10057,...
  • Page 2 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 (MSDS) and follow your employer’s safety practices. MSDS forms are available from your welding distributor or from the manufacturer. 5.f. Also see item 1.b. SQUARE WAVE TIG 355...
  • Page 4 During Welding, Cutting and Other Hot Work”, available from NFPA, 1 Batterymarch Park,PO box 9101, Quincy, Ma 022690-9101. 6.j. Do not use a welding power source for pipe thawing. Refer to http://www.lincolnelectric.com/safety for additional safety information. SQUARE WAVE TIG 355...
  • Page 5 4. Garder tous les couvercles et dispositifs de sûreté à leur place. talons sans revers, et chaussures montantes. 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. SQUARE WAVE TIG 355...
  • Page 6 2004/108/EC. It was manufactured in conformity with a national standard that implements a harmonized standard: EN 60974-10 Electromagnetic Compatibility (EMC) Product Standard for Arc Welding Equipment. It is for use with other Lincoln Electric equipment. It is designed for industrial and professional use. Introduction All electrical equipment generates small amounts of electromagnetic emission.
  • Page 7 Screening of the entire welding installation may be considered for special applica- tions. 1 _________________________ 1 Portions of the preceding text are contained in EN 60974-10: “Electromagnetic Compatibility (EMC) prod- uct standard for arc welding equipment.” SQUARE WAVE TIG 355...
  • Page 8 Parts Manual ..............P-196 SQUARE WAVE TIG 355...

  • Page 9: Table Of Contents

    Technical Specifications Square Wave TIG 355 ........

  • Page 10: Technical Specifications Square Wave Tig 355

    INSTALLATION TECHNICAL SPECIFICATIONS - SQUARE WAVE TIG 355 INPUT - SINGLE PHASE ONLY Input Voltages: Input Currents @ 350A/34 VDC RATED OUTPUT Duty Cycle Amps Volts at Rated Amperes 40% Duty Cycle 34 v 60% Duty Cycle 32 v 100% Duty Cycle...

  • Page 11: Safety Precautions

    • Insulate yourself from the work and ground. reduce or eliminate radiated interference. • Always wear dry insulating gloves. The Square Wave TIG 355 has been field tested under recommended installation conditions. It complies with Only qualified personnel should install, use, or service FCC allowable limits for radiation.

  • Page 12: Input Connections

    Use a single phase line or one phase of a two or three phase line. Refer to the connection diagram located on the inside of the cover of the Reconnect Panel. Also See Figure A.2. SQUARE WAVE TIG 355...

  • Page 13: Input Supply Connections

    See Table A.2. Also called “inverse time” or “thermal/magnetic” circuit breakers. These circuit breakers have a delay in tripping action that decreases as the magnitude of the current increases. SQUARE WAVE TIG 355...
  • Page 14 INSTALLATION The Square Wave TIG 355 should be permanently wired into the power system. Plugs or connectors are not recommended. TABLE A.1 RECOMMENDED INPUT WIRE AND FUSE SIZES For all Stick, DC TIG, and Balanced AC TIG Welding Based on the 1990 U.S. National Electrical Code...

  • Page 15: Output Connections

    Lengths up to 100 to 200 ft 200 to 250 ft Machine Size 100 ft (30 m) (30 to 61 m) (61 to 76 m) 350 Amp 40% Duty Cycle #1 (45mm 1/0 (55mm 2/0 (70mm SQUARE WAVE TIG 355...

  • Page 16: Stick Electrode Cable Connection

    Use a nonmetallic drain line from the electrode connection to the drain or water recirculating pump. For other water coolers or torches, consult the manu- facturer’s instructions for the water cooler or TIG torch being used. SQUARE WAVE TIG 355...
  • Page 17 Auxiliary Power ..............B-21 SQUARE WAVE TIG 355...

  • Page 18: Operation

    • Keep flammable material away. • Do not weld on containers that have held com- bustibles. ARC RAYS can burn. • Wear eye, ear, and body protection. Observe additional Safety Guidelines detailed in the beginning of this manual. SQUARE WAVE TIG 355...

  • Page 19: General Description

    OPERATION GENERAL DESCRIPTION DESIGN FEATURES AND ADVANTAGES • Designed to NEMA EW-1 and International IEC-974 The Square Wave TIG 355 is a constant current, single Standards. range square wave AC/DC TIG (GTAW) arc welding power source with built-in high frequency stabilization.

  • Page 20: Welding Capability

    • 115 Volt receptacle with 15 amp circuit breaker. WELDING CAPABILITY • 220 Volt European (Schuko) type receptacle with 2 The Square Wave TIG 355 is NEMA Class II (40) amp circuit breaker for water coolers (50/60Hz Power Source rated 350 amps at 34 volts, 40% duty machines only).

  • Page 21: Controls And Settings

    3. 2-STEP/4-STEP SWITCH 9. AUTO-BALANCE™ LED 14. START CONTROLS 4. HIGH FREQUENCY SWITCH 10. AFTERFLOW 15. PULSE CONTROLS 5. DIGITAL VOLTMETER/AMMETER 11. STICK ARC FORCE 16. CRATER FILL CONTROLS 6. PEAK CURRENT CONTROL 17. STATUS INDICATOR LEDs SQUARE WAVE TIG 355...
  • Page 22 Preflow time. The read true RMS currents, particularly when AC Arc switch can be released once an arc is estab- TIG welding aluminum. AC only ammeters lished. may read as much as 40% low when measur- ing AC TIG welding currents. SQUARE WAVE TIG 355...
  • Page 23 The arc will be softer and will have less spatter but positive current produces the “cleaning” or oxide may be more prone to sticking. removal on aluminum, this setting is used for heav- ily oxidized aluminum. SQUARE WAVE TIG 355...
  • Page 24 Start Current Display Pushbutton Background % Peak Current Control — Controls the background (low pulse) current from zero to 100% of the peak current set and controlled by the Peak Current control (Item 6) and the Amptrol. SQUARE WAVE TIG 355...
  • Page 25 Spot Time. The current control (item 1) switch must be in LOCAL when using Crater Fill. OFF: Locks out Crater Fill controls. FIGURE B.2 – STATUS INDICATOR LIGHT SEQUENCE SQUARE WAVE TIG 355 SQUARE WAVE TIG 355...
  • Page 26 Function Panel. See Figure B.2. • CRATER FILL LED is on during the Fade-Out The Status Indicator LED circuit board includes a downslope and final current periods. receptacle for plugging in the circuit board included with the Optional Interface Kit. SQUARE WAVE TIG 355...

  • Page 27: Lower Case Front Controls

    OPERATION B-11 B-11 LOWER CASE FRONT CONTROLS Refer to Figure B.3 for the location of the following controls. FIGURE B.3 – LOWER CASE FRONT CONTROLS SQUARE WAVE TIG 355...
  • Page 28 However, the LEDs tings. The fittings conform to CGA (Compressed for Gas and Water and High Frequency will still Gas Association) standards. Use a water line light. strainer to prevent particles from jamming the water valve. SQUARE WAVE TIG 355...

  • Page 29: Hand And Foot Amptrol Operation

    Amptrol approximately 1/4 of the way down, or to nearly 70 amps, in order to start the arc. Merely depressing the Amptrol to its 2 amp mini- mum position will not start the arc. SQUARE WAVE TIG 355...
  • Page 30 OPERATION B-14 B-14 FIGURE B.4 – AMPTROLS USED WITH CURRENT CONTROL IN THE LOCAL POSITION FIGURE B.5 – AMPTROLS USED WITH CURRENT CONTROL IN REMOTE POSITION SQUARE WAVE TIG 355...

  • Page 31: Welding Operation

    4. Preset the current with the Current control and the INITIAL START-UP Ammeter. Be sure the Square Wave TIG 355 has been installed 5. Set the desired Arc Force. (See CONTROLS AND correctly with respect to location, high frequency pro- SETTINGS, item 11, “Arc Force.”)
  • Page 32 LOCAL OR REMOTE CURRENT CONTROL PRESET START SWITCH ON CURRENT START CURRENT SET HIGHER THAN PRESET CURRENT (HOT START) START TIME: VARIABLE ALL OTHER PANEL SWITCHES OFF REMOTE AMPTROL CONTROLS FROM 2 AMPS UP TO PRESET CURRENT SQUARE WAVE TIG 355...
  • Page 33 LOCAL OR REMOTE CURRENT CONTROL PULSE SWITCH ON PULSES PER SECOND PRESET BACKGROUND % DUTY CYCLE CURRENT (PEAK) PULSE % ON ALL OTHER LOWER PANEL SWITCHES BACKGROUND % CURRENT REMOTE AMPTROL CONTROLS FROM 2 AMPS UP TO PRESET CURRENT SQUARE WAVE TIG 355...
  • Page 34 THE SPOT TIMER CAN BE USED TO TIME A PROGRAMMED SEQUENCE OF START AND/OR PULSE UP TO 5 SECONDS LONG, OPTIONALLY FOLLOWED BY CRATER FILL. IF CRATER FILL IS USED, FADE-OUT BEGINS AT THE END OF THE SPOT TIME. SQUARE WAVE TIG 355...
  • Page 35 (5) TIG torch nozzles are typically made from alumina ceramic. Special applications may require lava nozzles, which are less prone to breakage, but cannot withstand high temperatures and high duty cycles. Currents above 350 amps require metal nozzles on water cooled torches. SQUARE WAVE TIG 355...

  • Page 36: Tig Welding Sequence Of Operation (2-Step Mode

    Amptrol. This opens the gas and water valves to automatically purge air from the hose and torch. After a time determined by the Preflow con- trol setting, the high frequency becomes available to strike the arc. SQUARE WAVE TIG 355...

  • Page 37: Overload Protection

    Press and release the Arc Start switch a second time to stop The Square Wave TIG 355 provides 15 amps of 115 the arc. When the Afterflow timer completes the volt AC power at a standard NEMA 5-15R receptacle, cycle, the gas and water valves close.
  • Page 38 NOTES B-22 B-22 SQUARE WAVE TIG 355...
  • Page 39 Options / Accessories ..............C-2 SQUARE WAVE TIG 355...
  • Page 40 ACCESSORIES OPTIONS/ACCESSORIES The following options/accessories are available for Solid State Relays (SSRs): your Square Wave TIG 355 from your local Lincoln K847-DC – Can switch up to 40VDC, 2 amps max- Electric Distributor. imum load. Package of two. Undercarriage (K841) – Includes a platform, wheels, K847-AC –...
  • Page 41 Major Component Location .............D-4 SQUARE WAVE TIG 355...
  • Page 42 PROCEDURE This procedure ensures that the power factor capaci- tors are discharged, for greater safety when you are working on the Square Wave TIG 355 with INPUT POWER REMOVED. 1. Remove input power to the machine. 2. With a 5/16" nutdriver, remove the sheet metal screws that hold the right case side in place.
  • Page 43 1. Disconnect power supply lines to the machine 5. The fan motors have sealed ball bearings and before performing periodic maintenance. require no maintenance. FIGURE D.1 – POWER FACTOR CAPACITOR DISCHARGE DETAILS SQUARE WAVE TIG 355...
  • Page 44 2. INPUT CONTACTOR 3. RECONNECT PANEL 4. PILOT TRANSFORMER 5. FAN AND FAN MOTOR 6. INPUT POWER FACTOR CAPACITOR 7. MAIN TRANSFORMER 8. CHOKE 9. HIGH VOLTAGE TRANSFORMER 10. PC BOARDS (POWER, CONTROL) 11. CASE FRONT SQUARE WAVE TIG 355...
  • Page 45 INTERLOCK INTERLOCK HI-FREQ AND GAS/WATER 115VAC - SNUBBER 115VAC FANS 115VAC RECEPTACLE BOARD CONTROL TRANSFORMER 115VAC INPUT CONTACTOR POWER BY-PASS FACTOR BOARDS WORK CAPACITORS POLARITY SWITCH SHUNT START/ ELECTRODE MAIN STOP TRANSFORMER HI-FREQ TRANSFORMER PILOT TRANSFORMER SQUARE WAVE TIG 355...
  • Page 46 TRANSFORMER PILOT TRANSFORMER GENERAL DESCRIPTION The Square Wave TIG 355 is a constant current, single A reconnect panel allows the user to configure the pilot range square wave AC/DC TIG (GTAW) arc welding transformer, the power factor capacitors, and the main power source with built-in high frequency stabilization.
  • Page 47 The electrode sense, the remote control and the trigger signals are applied through the feed – thru board to the control board. NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion SQUARE WAVE TIG 355...
  • Page 48 The high frequency transformer transfers the high frequency “spark” to the electrode terminal. NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion SQUARE WAVE TIG 355...
  • Page 49 DC is applied to the machine output terminals. FIGURE E.5a – SCR BRIDGE AND CHOKE CONFIGURATION FOR DC WELDING NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion SQUARE WAVE TIG 355...
  • Page 50 AC square wave is developed and applied to the out- bridge. The electrode terminal is connected to the put terminals. FIGURE E.6a – SCR BRIDGE AND CHOKE CONFIGURATION FOR AC WELDING NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion SQUARE WAVE TIG 355...
  • Page 51 SCR output. the ON state and the remainder of the time in the OFF state. The amount of time spent in the ON state is con- trolled by the gate. SQUARE WAVE TIG 355...
  • Page 52 Should the output current exceed approximately 400 amps, an electronic circuit will reduce and limit the output current. The machine will continue to limit the output current until the overload is removed. SQUARE WAVE TIG 355...
  • Page 53 Rest after Repair ..............F-93 SQUARE WAVE TIG 355...

  • Page 54: How To Use Troubleshooting Guide

    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.

  • Page 55: Pc Board Troubleshooting Procedures

    Do not touch electrically hot parts. - 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- CAUTION er failure analysis.
  • Page 56 Contactor Test. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 57 (more than 10% over rated). CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 58 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 59 CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 60 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 61 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 62 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 63 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 64 CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 65 Test. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 66 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 67 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 68 CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 69 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 70 Replace. CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 71 CAUTION If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 1-888-935-3877. SQUARE WAVE TIG 355...
  • Page 72 NOTES F-20 F-20 SQUARE WAVE TIG 355...

  • Page 73: Input Power Factor Capacitor Voltage Check And Discharge Procedure

    Call 1-888-935-3877. TEST DESCRIPTION This procedure ensures that the Power Factor Capacitors are discharged, for greater safety when you are working on the Square Wave TIG 355 with INPUT POWER REMOVED. MATERIALS NEEDED Volt/Ohmmeter Capable Of Testing 600 VAC 5/16"...
  • Page 74 4. If capacitor voltage is zero, you may begin from discharging normally. working on the Square Wave TIG 355. 5. If any voltage is present, DISCHARGE EACH INDIVIDUAL CAPACITOR as follows: SQUARE WAVE TIG 355...

  • Page 75: Arc Start Trigger Circuit Test

    ARC START TRIGGER CIRCUIT TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 76 It should be zero ohms. See the Wiring Figure F.2. Diagram. 6. With the volt/ohmmeter, check for 24 VAC at 8. After the tests are complete, install the front pins 1J9 to 3J9. control panel, using the 5/16" nutdriver. SQUARE WAVE TIG 355...
  • Page 77 FEED - THRU PROTECTION BOARD BOARD CONTROL REMOTE TRANSFORMER #204 1J16 1J18 8J23 3J22 RECEPTACLE 4.2 ohms 4.2 ohms max. max. CONTROL BOARD 24VAC START SWITCH #207 3J16 5J18 5J23 6J22 4.2 ohms 4.2 ohms max. max. SQUARE WAVE TIG 355...
  • Page 78 NOTES F-26 F-26 SQUARE WAVE TIG 355...

  • Page 79: Power Board Test

    POWER BOARD TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 80 5/16" nutdriver. ELECTRIC SHOCK can kill. • With input power ON, there are high voltages inside the machine. Do not reach into the machine or touch any internal part of the machine while power is on. SQUARE WAVE TIG 355...
  • Page 81 -15VDC LED 2 ON IJ2(+) to 2J2 Unregulated DC +14VDC None NOTE: LED 3 should be ON when gate signal is applied to SCR 1. LED 4 should be ON when gate signal is applied to SCR 4. SQUARE WAVE TIG 355...
  • Page 82 NOTES F-30 F-30 SQUARE WAVE TIG 355...

  • Page 83: Input Contactor Test

    INPUT CONTACTOR TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 84 Also perform the Pilot Transformer Test. the machine or touch any internal part of the machine • If 120 VAC is present and the contactor does not while power is on. activate, the input contactor is faulty. Replace. SQUARE WAVE TIG 355...
  • Page 85 • If the resistance is low, the contactor is faulty. Replace. 6. After the tests are completed and the problem repaired, install the machine sides and top, using the 5/16" nutdriver. SQUARE WAVE TIG 355...
  • Page 86 #241 #272 START CR 1 T2 PILOT .33 OHMS OVERVOLTAGE INTERLOCK TRANSFORMER MAX. 10J2 10J3 FEEDBACK 8J15 2J17 #242 #273 #243 CR 1 FEED - THRU POWER CONTROL BOARD BOARD BOARD #244 N. C. SECONDARY THERMOSTAT SQUARE WAVE TIG 355...

  • Page 87: Pilot Transformer Test

    PILOT TRANSFORMER TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 88 7. After the tests are completed and the problem repaired, install the machine sides and top, 5. Turn on input power to the machine. using the 5/16" nutdriver. SQUARE WAVE TIG 355...

  • Page 89: Feed-Thru Pc Board Test

    FEED-THRU PC BOARD TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 90 7. Test for the resistances between the check points listed on the Feed-Thru PC Board Resistance Test Points Chart. See Figures F.9 and F.10. • If any of the resistances are out of specifica- tion, replace the feed-thru PC board. SQUARE WAVE TIG 355...
  • Page 91 FIGURE F.9 – FEED-THRU PC BOARD PLUG DETAILS - PLUGS J15 AND J16 FIGURE F.10 - FEED-THRU PC BOARD PLUG DETAILS – PLUGS J17 AND J18 7 6 5 8 7 6 3 2 1 3 2 1 VIEW FROM EDGE OF BOARD SQUARE WAVE TIG 355...
  • Page 92 4.2 OHMS (3.9 Typical) 6J16 to 8J18 L16 and Board Trace 4.2 OHMS (3.9 Typical) 7J16 to 7J18 L17 and Board Trace 4.2 OHMS (3.9 Typical) 8J16 to 6J18 L18 and Board Trace 4.2 OHMS (3.9 Typical) SQUARE WAVE TIG 355...

  • Page 93: Protection Pc Board Test

    PROTECTION PC BOARD TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 94 6. Test for the resistances between the check nutdriver. points listed on the Protection PC Board Resistance Test Points Chart. • If any of the resistances are out of specifica- tion, replace the protection PC board. SQUARE WAVE TIG 355...
  • Page 95 L5 and Board Trace 4.2 OHMS (3.9 Typical) 6J22 to 5J23 L6 and Board Trace 4.2 OHMS (3.9 Typical) 3J22 to 8J23 L3 and Board Trace 4.2 OHMS (3.9 Typical) 7J23 to 8J23 Board Trace Zero (0) Ohms SQUARE WAVE TIG 355...
  • Page 96 NOTES F-44 F-44 SQUARE WAVE TIG 355...

  • Page 97: Main Transformer Test

    MAIN TRANSFORMER TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 98 5. Check the reconnect panel to make sure that the single phase AC power supplied to the 7. Turn on input power to the machine. machine is properly connected. 6. Locate leads X1 though X7. See Figure F.12. SQUARE WAVE TIG 355...
  • Page 99 • If any of the secondary or auxiliary voltages is using the 5/16" nutdriver. missing or out of specification and the correct input voltage is applied to the primary wind- ing, the main transformer may be faulty. SQUARE WAVE TIG 355...
  • Page 100 NOTES F-48 F-48 SQUARE WAVE TIG 355...

  • Page 101: Control Transformer (T5) Voltage Test

    CONTROL TRANSFORMER (T5) VOLTAGE TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 102 5. Remove input power to machine. • With input power ON, there are high voltages inside the machine. Do not reach into the machine or touch any internal part of the machine while power is on. 3. Turn input power ON. SQUARE WAVE TIG 355...
  • Page 103 White to Blue 5 to 6 16VAC leads going to 1J16 on the feed-thru PC Red to White 10 to 5 18VAC board and 1J9 on the control PC board. Red to Red 10 to 12 36VAC SQUARE WAVE TIG 355...
  • Page 104 NOTES F-52 F-52 SQUARE WAVE TIG 355...

  • Page 105: Control Pc Board Test

    CONTROL PC BOARD TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 106 Control PC Board Schematic. are high voltages inside the machine. Do not reach into the machine or touch any internal part of the machine while power is on. 5. Turn on input power to the machine. SQUARE WAVE TIG 355...
  • Page 107 PC board and the correct voltage signals 7. After the tests are completed and the problem are NOT being generated by the control PC repaired, install the front control panel, using board, the control PC board may be faulty. the 5/16” nutdriver. SQUARE WAVE TIG 355...
  • Page 108 Low logic signal for 0 - 2 VDC Stick Mode DC OCV Boost DC Mode (CR3) relay R8 to 5J13 Low logic signal for 0 - 2 VDC Stick Mode AC OCV Boost AC Mode (CR2) relay SQUARE WAVE TIG 355...

  • Page 109: Static Scr Test

    STATIC SCR TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 110 7. Remove the red insulating paint from heat sink To further check SCR functions, use an SCR test points. See Figure F.18. DO NOT DISAS- tester and proceed to the Active SCR test. SEMBLE THE HEAT SINKS. SQUARE WAVE TIG 355...
  • Page 111 F-59 STATIC SCR TEST (continued) FIGURE F.18 – SCR TEST POINTS SCR3 Cathode SCR 3 & 4 Anode and Negative Plate SCR4 Anode SCR1 Cathode SCR1 & 2 Choke Cathode and SCR2 Lead Positive Plate Anode SQUARE WAVE TIG 355...
  • Page 112 NOTES F-60 F-60 SQUARE WAVE TIG 355...

  • Page 113: Active Scr Test

    ACTIVE SCR TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 114 5. Remove plug J1 from the power PC board. See 10. Replace any SCR or SCR assembly that does Figure F.19. not pass the test in Step 9. 6. Place the polarity switch (S1) in a “DC” position. SQUARE WAVE TIG 355...
  • Page 115 F-63 ACTIVE SCR TEST (continued) FIGURE F.20 – SCR TEST POINTS SCR3 Cathode SCR 3 & 4 Anode and Negative Plate SCR4 Anode SCR1 Cathode SCR1 & 2 Cathode and Choke SCR2 Positive Plate Lead Anode SQUARE WAVE TIG 355...
  • Page 116 4. Open switch SW-1, disconnect the gate lead (G), and reverse the (A) and (C) leads on the SCR. Close switch SW-1. The voltmeter should read zero. If the voltage is higher than zero, the SCR is shorted. SQUARE WAVE TIG 355...
  • Page 117 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....50V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 118 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....50V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 119 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....50V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 120 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....50V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 121 The TIG 355 display read 350 amps at 34 VDC. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....20V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 122 The TIG 355 display read 350 amps at 34 VAC. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....20V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 123 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....50V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...
  • Page 124 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode terminal, (-) probe to work terminal. SCOPE SETTINGS Volts/Div.....50V/Div. Horizontal Sweep ..2 ms/Div. Coupling......DC Trigger......Internal SQUARE WAVE TIG 355...

  • Page 125: Control Pc Board Removal And Replacement

    CONTROL PC BOARD REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 126 7. Carefully install the molex plugs that connect to the control PC board. 5. Carefully remove the control PC board. Be sure to observe static electricity cautions. 8. Replace the front control panel and tighten the sheet metal screws with the 5/16" nutdriver. SQUARE WAVE TIG 355...

  • Page 127: Power Pc Board Removal And Replacement

    POWER PC BOARD REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 128 PC board. 8. Replace the front control panel and tighten the 5. Carefully remove the power PC board. Be sure sheet metal screws with the 5/16" nutdriver. to observe static electricity cautions. SQUARE WAVE TIG 355...

  • Page 129: Input Contactor Removal And Replacement

    INPUT CONTACTOR REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 130 12. Carefully remove the contactor and the bracket assembly from the case back. 6. With the slot head screw driver, remove the copper strap, the heavy lead, and the small capacitors from the output side of the contactor. SQUARE WAVE TIG 355...
  • Page 131 19. With the slot head screw driver, attach the input leads to the L1 and L2 terminals on the input contactor. 20. With the 5/16" nutdriver, install the rear access panel, case sides and top. SQUARE WAVE TIG 355...
  • Page 132 NOTES F-80 F-80 SQUARE WAVE TIG 355...

  • Page 133: Fan Motor And Blade Removal And Replacement

    FAN MOTOR AND BLADE REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 134 5. With the 11/32" wrench, remove the nuts, lock 11. With the 5/16" nutdriver, install the case top washers, and flat washers that mount the fan and sides. motor to the fan bracket. 6. Cut any cable ties or wire leads. SQUARE WAVE TIG 355...

  • Page 135: Output Rectifier Removal And Replacement

    OUTPUT RECTIFIER REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 136 OUTPUT RECTIFIER REMOVAL AND REPLACEMENT (continued) FIGURE F.26 – OUTPUT RECTIFIER CONNECTION DETAILS Step 13 Step 12 Step 11 Step 10 Step 7 SEE DETAIL “C” Step 5 Step 9 Step 6 Step 15 Step 8 DETAIL C SQUARE WAVE TIG 355...
  • Page 137 See Wiring the negative plate. Diagram). Use a molex pin extractor. Note 26. Attach plug J1 to the power PC board. lead placement for reassembly. 27. With the 5/16" nutdriver, install the case top and sides. SQUARE WAVE TIG 355...
  • Page 138 NOTES F-86 F-86 SQUARE WAVE TIG 355...

  • Page 139: Scr Removal And Replacement

    SCR REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or 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.
  • Page 140 1/2 turn each until the heat sinks 7. Apply a thin (0.001” to 0.003”) layer of PEN- are loose. Remove the nuts and leaf spring. IT ETROX A-13 (Lincoln Electric #E2529) or PEN- IS RECOMMENDED THAT NEW HARDWARE, ETROX A, heat sink compound, to each heat LEAF SPRING AND HOUSING BE USED FOR sink’s SCR mounting surface.
  • Page 141 A 1/4-28 thread screws until finger tight. (See Figure requires a different tightening procedure than a F.29.) 1/4-20 thread. NOTE WHICH THREAD IS ON YOUR CAP SCREWS BEFORE PERFORM- ING THE ASSEMBLY PROCEDURE. SQUARE WAVE TIG 355...
  • Page 142 Tighten second cap screw 1/2 turn. force. d. Tighten first cap screw 1/2 turn. 7) Perform the Active SCR Test. e. Tighten second cap screw 1/2 turn. f. Tighten first cap screw 1/4 turn. Stop. The assembly now has proper clamping force. SQUARE WAVE TIG 355...
  • Page 143 See Figure F.31. 6) Re-inspect the SCR for proper seating. 7) Clamp the cap screws. Use the procedure for 1/4-28 cap screws or 1/4-20 cap screws, depending on which you have. SQUARE WAVE TIG 355...
  • Page 144 Tighten the first cap screw 1/2 turn. e. Tighten the second cap screw 1/4 turn. Tighten the first cap screw 1/8 turn. g. Tighten the second cap screw 1/8 turn. Stop. The assembly now has the proper clamping force. SQUARE WAVE TIG 355...
  • Page 145 NOTE: Power factor correction capacitors are standard on all models. The capacitors cause high idle currents, but idle power is low. OPEN CIRCUIT VOLTAGES Stick Mode OCV AC 60-70 DC 60-70 TIG Mode OCV AC 60-70 DC 60-70 SQUARE WAVE TIG 355...
  • Page 146 IMPORTANT: IF OTHER TYPE METERS ARE USED RESULTS MAY NOT BE ACCURATE MAIN TRANSFORMER SECONDARY VOLTAGES (SEE FIGURE F.32) Test Points Voltages X1 to X2 84 to 89VAC X3 to X4 117 to 125VAC X5 to X6 22 to 24VAC X2 to X7 77 to 81VAC SQUARE WAVE TIG 355...
  • Page 147 Meter PC Board (M15893) Layout ......................G-17 * NOTE: Many PC Board Assemblies are now totally encapsulated, surface mounted and or multi-layered and are therefore considered to be unserviceable. Assembly drawings of these boards are no longer provided. SQUARE WAVE TIG 355...
  • Page 148 MODE 2 STEP/4 STEP FREQUENCY THIS SHEET CONTAINS PROPRIETARY INFORMATION UNLESS OTHERWISE SPECIFIED TOLERANCE EQUIP. THE LINCOLN ELECTRIC CO. SQUARE WAVE TIG 355 OWNED BY THE LINCOLN ELECTRIC CO. AND IS ON HOLE SIZES PER E2056 5‐8‐92E TYPE ON 2 PLACE DECIMALS IS .02 CLEVELAND, OHIO U.S.A.
  • Page 149 BACKGROUND (+)15 V 11J12 4J601 CJ701 CRATER FILL CP602 12J12 3J601 3P602 3J701 TS701 5‐14‐93F EQUIP. SQUARE WAVE TIG 355 THE LINCOLN ELECTRIC CO. TYPE CLEVELAND, OHIO U.S.A. MACHINE SCHEMATIC SUBJECT SCALE NONE SHT. 2522 4‐2‐92 G2113 DATE REF. SUP'S'D'G NOTE: This diagram is for reference only.
  • Page 150 NOT SHOW THE EXACT COMPONENTS OR CIRCUITRY OF CONTROLS HAVING A COMMON CODE EARTH GROUND CONNECTION NUMBER. UNLESS OTHERWISE SPECIFIED TOLERANCE Ch'ge.Sht.No. EQUIP. THE LINCOLN ELECTRIC CO. CV WELDERS ON HOLES SIZES PER E‐2056 TYPE 2‐16‐90 ON 2 PLACE DECIMALS IS + .O2 ON 3 PLACE DECIMALS IS + .OO2...
  • Page 151 FRAME CONNECTION EARTH GROUND CONNECTION THIS SHEET CONTAINS PROPRIETARY INFORMATION UNLESS OTHERWISE SPECIFIED TOLERANCE EQUIP. SQUARE WAVE TIG 350 THE LINCOLN ELECTRIC CO. THE LINCOLN ELECTRIC CO. ON HOLE SIZES PER E2056 OWNED BY AND IS TYPE 5‐29‐90SPA ON 2 PLACE DECIMALS IS .02 CLEVELAND, OHIO U.S.A.
  • Page 152 NOT SHOW THE EXACT COMPONENTS OR CIRCUITRY OF CONTROLS HAVING A COMMON CODE EARTH GROUND CONNECTION NUMBER. UNLESS OTHERWISE SPECIFIED TOLERANCE EQUIP. THIS SHEET CONTAINS PROPRIETARY INFORMATION SQARE WAVE TIG 350 THE LINCOLN ELECTRIC CO. ON HOLE SIZES PER E2056 THE LINCOLN ELECTRIC CO. TYPE OWNED BY AND IS 5‐29‐90SPA CLEVELAND, OHIO U.S.A.
  • Page 153 ELECTriCaL DiaGramS SChEmaTiC - pOWEr pC bOarD (L8086) NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. SQUarE WaVE TiG  355...
  • Page 154 Adjust EQUIP. N.A. SINCE COMPONENTS OR CIRCUITRY ON A PRINTED CIRCUIT BOARD MAY CHANGE Ch'ge.Sht.No. THE LINCOLN ELECTRIC CO. SQUARE WAVE 355 UNLESS OTHERWISE SPECIFIED TOLERANCE TYPE WITHOUT AFFECTING THE INTERCHANGEABILITY OF A COMPLETE BOARD, THIS DIAGRAM MAY ON HOLES SIZES PER E‐2056 5‐8‐92E...
  • Page 155 ELECTriCaL DiaGramS SChEmaTiC - UppEr CONTrOL pC bOarD (S20572) NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. SQUarE WaVE TiG  355...
  • Page 156 G-10 G-10 ELECTriCaL DiaGramS SChEmaTiC - iNpUT bypaSS pC bOarD (S23045) NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. SQUarE WaVE TiG  355...
  • Page 157 G-11 G-11 ELECTriCaL DiaGramS SChEmaTiC - SNUbbEr pC bOarD (m17499) NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. SQUarE WaVE TiG  355...
  • Page 158 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 159 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 160 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 161 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 162 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 163 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.

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