Lincoln Electric SQUARE WAVE TIG 175 Service Manual
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Lincoln Electric SQUARE WAVE TIG 175 Service Manual

Lincoln Electric SQUARE WAVE TIG 175 Service Manual

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SQUARE WAVE TIG 175
For use with machines having Code Numbers:
10265
SERVICE MANUAL
SVM126-A
| Issue D ate 99, Mar
© 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 175

  • 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 175 For use with machines having Code Numbers: 10265 SERVICE MANUAL...
  • Page 2 351040, 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 SAFETY ARC RAYS can burn. ELECTRIC SHOCK can 4.a. Use a shield with the proper filter and cover kill. plates to protect your eyes from sparks and 3.a. The electrode and work (or ground) circuits the rays of the arc when welding or observing are electrically “hot”...
  • Page 4 SAFETY WELDING SPARKS can CYLINDER may explode cause fire or explosion. if damaged. 6.a. Remove fire hazards from the welding area. 7.a. Use only compressed gas cylinders If this is not possible, cover them to prevent containing the correct shielding gas for the the welding sparks from starting a fire.
  • Page 5 SAFETY 5. Toujours porter des lunettes de sécurité dans la zone de PRÉCAUTIONS DE SÛRETÉ soudage. Utiliser des lunettes avec écrans lateraux dans les zones où l’on pique le laitier. Pour votre propre protection lire et observer toutes les instruc- tions et les précautions de sûreté...

  • Page 6: Table Of Contents

    Protective Circuits ........................E-8 Troubleshooting Section F How to Use Troubleshooting Guide ..................F-2 PC Board Troubleshooting Procedures .................F-3 Troubleshooting Guide......................F-4 Test Procedures........................F-15 Oscilloscope Waveforms......................F-29 Repair and Replacement Procedures ..................F-39 Retest After Repair.......................F-57 Electrical Diagrams........................Section G Parts Manual ..........................P-281 SQUARE WAVE TIG 175...
  • Page 7 Input Connections ........................A-4 Input Reconnect Procedure......................A-4 Output Connections........................A-5 Connections for TIG Welding....................A-5 TIG Torch Connection....................A-5 Work Cable Connection ....................A-5 Shielding Gas Connection....................A-5 Remote Control Connection..................A-6 Connections for Stick Welding ....................A-6 Stick Electrode Cable and Work Cable Connection.............A-6 SQUARE WAVE TIG 175...

  • Page 8: Installation

    INSTALLATION TECHNICAL SPECIFICATIONS - Square Wave TIG 175 INPUT - SINGLE PHASE ONLY Standard Input Current at Code Voltage Rated Output Number 208/230/1/60 59/53 AC/DC Stick & DC TIG 72/65 AC TIG 10265 460/575/1/60 27/22 AC/DC Stick & DC TIG 33/26 AC TIG...

  • Page 9: Location

    50 feet (15.2m). There should be good The Square Wave TIG 175 should be lifted by two or electrical contact between this conduit and the more people or with a hoist. Its lifting handles are welder case ground.

  • Page 10: Input Connections

    1 Also called “inverse time” or “thermal/magnetic” circuit breakers; circuit breakers which have a delay in tripping action that decreases as the magni- 5. Replace sheet metal cover and all screws. tude of the current increases. SQUARE WAVE TIG 175...

  • Page 11: Output Connections

    INPUT LEADS L1 & L2 A work cable with attached work clamp is factory con- nected to the Square Wave TIG 175. To minimize high frequency interference, refer to Machine BACK VIEW OF LINE SWITCH Grounding and High Frequency Interference Protection section of this manual for the proper pro- FIGURE A.1 Reconnect Leads...

  • Page 12: Remote Control Connection

    Refer to Included Equipment in the Operation Section of this manual for STICK welding equipment which is included with the Square Wave TIG 175. An electrode holder with cable is supplied with the Square Wave TIG 175. Turn the Power Switch “OFF”.
  • Page 13 Welding Capability .........................B-2 Controls and Settings ........................B-3 Operating Steps ...........................B-4 Welding in TIG Mode ......................B-4 Remote Control Operation ...................B-4 Benefits of the Square Wave Design ................B-4 Welding in Stick Mode ......................B-5 Recommended Electrode Amperage Ranges ...............B-5 SQUARE WAVE TIG 175...

  • Page 14: Operation

    • Do not weld on containers that WELDING CAPABILITY have held combustibles. The Square Wave TIG 175 is rated at 150 amps, 15 volts, at 25% duty cycle on a ten minute basis. It is ARC RAYS capable of higher duty cycles at lower output currents.

  • Page 15: Controls And Settings

    OPERATION CONTROLS AND SETTINGS All operator controls and adjustments are located on the front of the Square Wave TIG 175. Refer to Figure B.1 and corresponding explanations. FIGURE B.1 - CONTROL PANEL 1. POWER SWITCH & LIGHT 2. TIG/STICK SWITCH 3.

  • Page 16: Operating Steps

    (removal of aluminum oxide) of the will turn on and off automatically to start and stabilize the work piece. This is desirable on materials with a heavy oxide arc. In AC the TIG Arc Starter will turn on with the output SQUARE WAVE TIG 175...

  • Page 17: Welding In Stick Mode

    60 - 100 90 - 140 Mild steel procedures are based on recommended procedures listed in C2.10 8/94 and the maximum rating of the Square Wave TIG 175 Jet-LH MR procedures are based on Jet-LH 78 MR Blue Max procedures are based on C6.1 6/95...
  • Page 18 NOTES SQUARE WAVE TIG 175...
  • Page 19 SECTION C-1 SECTION C-1 ACCESSORIES TABLE OF CONTENTS -ACCESSORIES SECTION- Options / Accessories ........................C-2 SQUARE WAVE TIG 175...

  • Page 20: Accessories

    See publication E12.150 for parts kits breakdown. Platform - This undercarriage is designed specifically for the Square Wave TIG 175 power source. Its cast- Cut Length Consumables - TIG welding filler metals ers and wheels are factory assembled to a platform are available for welding stainless steel, mild steel, base that mounts the power source.
  • Page 21 SECTION D-1 SECTION D-1 MAINTENANCE TABLE OF CONTENTS -MAINTENANCE SECTION- Safety Precautions....................D-2 Routine and Periodic Maintenance ..............D-2 Fan Motor and Blade Replacement ..............D-2 Location of Maintenance Components ...............D-3 SQUARE WAVE TIG 175...

  • Page 22: Maintenance

    6. The fan motor has sealed ball bearings which require no maintenance. 7. The arc starter spark gap spacing is factory set at 0.015 inch. It typically will not require periodic Figure C.2 maintenance. Refinishing the contacts is not rec- SQUARE WAVE TIG 175...
  • Page 23 MAINTENANCE FIGURE D.2 — LOCATION OF MAINTENANCE COMPONENTS. Control PC Board Rectifier Fan Blade Assembly Electrode Polarity Switch Main Transformer Spark Gap Assembly Location Electrode/Gas Output Receptacle SQUARE WAVE TIG 175...
  • Page 24 NOTES SQUARE WAVE TIG 175...
  • Page 25 General Description .......................E-2 Output Rectification and Feedback Control ................E-3 High Voltage/High Frequency Circuit..................E-4 DC Welding Output ........................E-5 AC Welding Output ........................E-6 SCR Operation........................E-7 Protective Circuits ........................E-8 FIGURE E.1 Square Wave TIG 175 Block Logic Diagram. BY-PASS BOARD WORK POLARITY SWITCH ELECTRODE...

  • Page 26: Theory Of Operation

    THEORY OF OPERATION GENERAL DESCRIPTION The Square Wave TIG 175 is a constant current, single range AC/DC TIG (GTAW) arc welding power source with a built-in arc starter/stabilizer. It also has stick welding (SMAW) capability. The Square Wave TIG 175 is recom- mended for the TIG (GTAW) and stick (SMAW) welding processes within its output capacity of 12 to 175 amps, on both AC and DC polarity.

  • Page 27: Output Rectification And Feedback Control

    SCRs, which control the output of the machine. See SCR Operation . The control board monitors the thermostats, and also controls the gas solenoid valve, thermal light and the power “ON” light. NOTE: Unshaded areas of block logic diagrams are the subject of discussion. SQUARE WAVE TIG 175...

  • Page 28: High Voltage/High Frequency Circuit

    The high frequency transformer transfers the high frequency “spark” to the electrode terminal which is coupled to the TIG torch. NOTE: Unshaded areas of block logic diagrams are the subject of discussion. SQUARE WAVE TIG 175...

  • Page 29: Dc Welding Output

    DC output. Since the choke is in series with the negative leg of the bridge and also in series with the welding load, a filtered DC is applied to the machine output terminals. CHOKE ELECTRODE PRIMARY 1Ø WORK FIGURE E.5 DC Welding Current Generation. SQUARE WAVE TIG 175...

  • Page 30: Ac Welding Output

    SCRs to turn on at the appro- priate times, an AC square wave is developed and applied to the output terminals. CHOKE ELECTRODE PRIMARY 1Ø WORK FIGURE E.6 AC Square Wave Welding Current Generation. SQUARE WAVE TIG 175...

  • Page 31: Scr Operation

    This gate pulse must be more positive than the cathode voltage. Since there is a standard PN junc- INPUT CATHODE OUTPUT NOTE: AS THE GATE ANODE PULSE IS APPLIED GATE LATER IN THE CYCLE THE SCR OUTPUT IS DECREASED. GATE FIGURE E.7 SCR Operation SQUARE WAVE TIG 175...

  • Page 32: Protective Circuits

    Once the machine cools sufficiently the thermostats are self-resetting. If the thermostat shutdown is caused by excessive output or duty cycle and the fan NOTE: Unshaded areas of block logic diagrams are the subject of discussion. SQUARE WAVE TIG 175...
  • Page 33 ABNORMAL OPEN CIRCUIT VOLTAGE -DC TIG MODE ONE SCR NOT FUNCTIONING ..F-37 REPLACEMENT PROCEDURES SCR BRIDGE ASSEMBLY REMOVAL AND REPLACEMENT .............F-39 POLARITY SWITCH REMOVAL AND REPLACEMENT ...............F-45 HIGH VOLTAGE TRANSFORMER REMOVAL AND REPLACEMENT ........F-49 MAIN TRANSFORMER AND OUTPUT CHOKE REMOVAL AND REPLACEMENT ....F-53 RETEST AFTER REPAIR ........................F-57 SQUARE WAVE TIG 175...

  • Page 34: 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 35: Pc Board Troubleshooting Procedures

    “INSTALLED AND SWITCHED PC BOARDS TO VERIFY PROBLEM,” will help avoid - Tools which come in contact with the P.C. denial of legitimate PC board warranty claims. Board must be either conductive, anti-static or static-dissipative. SQUARE WAVE TIG 175...
  • Page 36 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 216-383-2531 or 1-888-935-3877. SQUARE WAVE TIG 175...
  • Page 37 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 216-383-2531 or 1-888-935-3877. SQUARE WAVE TIG 175...
  • Page 38 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 216-383-2531 or 1-888-935-3877.
  • Page 39 4. The control board may be faulty. 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 216-383-2531 or 1-888-935-3877.
  • Page 40 Installation section of this manual. 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 216-383-2531 or 1-888-935-3877.
  • Page 41 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 216-383-2531 or 1-888-935-3877. SQUARE WAVE TIG 175...
  • Page 42 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 216-383-2531 or 1-888-935-3877. SQUARE WAVE TIG 175...
  • Page 43 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 216-383-2531 or 1-888-935-3877.
  • Page 44 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 216-383-2531 or 1-888-935-3877.
  • Page 45 888-935-3877. 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 216-383-2531 or 1-888-935-3877. SQUARE WAVE TIG 175...
  • Page 46 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 216-383-2531 or 1-888-935-3877. SQUARE WAVE TIG 175...

  • Page 47: High Frequency Circuit Disable Procedure

    HIGH FREQUENCY CIRCUIT DISABLE PROCEDURE WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 48 .015” air gap. Tighten the set screw using the 5/64” Allen wrench. Secure Spark Gap to .375 to disable LEFT SIDE OF MACHINE FIGURE F.1 SPARK GAP ASSEMBLY SQUARE WAVE TIG 175...

  • Page 49: T1 Transformer Test

    T1 TRANSFORMER TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.

  • Page 50: Test Procedures

    G2986-[ ] S-W TIG 175 CONTROL PIN 7 (LEAD #230) PIN 10 (LEAD #201) PIN 6 (LEAD #209) PIN 1 (LEAD #210) PIN 2 (LEAD #232) PIN 4 (LEAD #204) FIGURE F.2 PLUG J6 ON CONTROL BOARD SQUARE WAVE TIG 175...
  • Page 51 PLUG J6 PIN 7 (LEAD #230) 115VAC PLUG J6 PIN 2 (LEAD #232) X1 TO X2 78VAC PRIMARY WINDINGS PRIMARY VOLTAGES H1 TO H2 208VAC H1 TO H3 230VAC NOTE: If the input voltages vary the secondary voltages will vary accordingly. SQUARE WAVE TIG 175...
  • Page 52 F-20 F-20 NOTES SQUARE WAVE TIG 175...

  • Page 53: Static Scr Test

    STATIC SCR TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 54 TIG 175 and remove the case wrap- around cover. 2. Locate and remove plug J1 from the control board. See Figure F.3. PLUG J1 REMOVED G2986-[ ] S-W TIG 175 CONTROL FIGURE F.3 PLUG J1 ON CONTROL BOARD SQUARE WAVE TIG 175...
  • Page 55 SCR Bridge Assembly. See SCR Bridge Assembly Removal and Replacement . 4. Repeat Step #3 testing SCR2, SCR3 and SCR4. SCR2 CATHODE SCR3 CATHODE SCR1 ANODE SCR4 ANODE SCR1 CATHODE/SCR2 ANODE SCR3 ANODE/SCR4 CATHODE FIGURE F.4 SCR TEST POINTS SQUARE WAVE TIG 175...
  • Page 56 F-24 F-24 NOTES SQUARE WAVE TIG 175...

  • Page 57: Active Scr Test

    ACTIVE SCR TEST WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 58 R2= 3 ohms/ 10 watts To test SCRs construct the circuit outlined above. Resistor values are plus or minus ten percent. The voltmeter scale should be low, approximately 0-5 or 0-10 volts DC. FIGURE F.5 ACTIVE SCR TEST SETUP SQUARE WAVE TIG 175...
  • Page 59 2 is released. If the voltmeter does 11. Replace plug J1 into the control not read, or reads only while SW-2 is board. depressed, the SCR or battery is defective (repeat Battery Test 12. Replace the case wrap-around Procedure above). cover. SQUARE WAVE TIG 175...
  • Page 60 F-28 F-28 NOTES SQUARE WAVE TIG 175...

  • Page 61: Normal Open Circuit Voltage Waveform-Ac Tig Mode

    50 volts and that each horizontal division represents 2 milliseconds in time. Horizontal Sweep ....2 ms/Div. Coupling .........DC Note: Scope probes connected at machine Trigger ........Internal output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 62: Normal Open Circuit Voltage Waveform-Dc Tig Mode

    50 volts and that each hori- zontal division represents 2 milliseconds in Horizontal Sweep ....2 ms/Div. time. Coupling .........DC Trigger ........Internal Note: Scope probes connected at machine output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 63: Normal Open Circuit Voltage Waveform-Ac Stick Mode

    50 volts and that each horizontal division represents 2 milliseconds in time. Horizontal Sweep ....2 ms/Div. Coupling .........DC Note: Scope probes connected at machine Trigger ........Internal output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 64: Normal Open Circuit Voltage Waveform-Dc Stick Mode

    50 volts and that each hori- zontal division represents 2 milliseconds in Horizontal Sweep ....2 ms/Div. time. Coupling .........DC Trigger ........Internal Note: Scope probes connected at machine output studs: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 65: Typical Output Voltage Waveform-Machine Loaded Ac Tig Mode

    2 milliseconds in time. The machine was loaded with a resistance grid bank. The grid load meters read 150 amps and 16VDC Note: Scope probes connected at machine output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 66: Typical Output Voltage Waveform-Machine Loaded Dc Tig Mode

    The machine was loaded with a resis- tance grid bank. The grid load meters read 150 amps and 16VDC Note: Scope probes connected at machine output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 67: Typical Output Voltage Waveform-Machine Loaded Ac Stick Mode

    2 milliseconds in time. The machine was loaded with a resistance grid bank. The grid load meters read 150 amps and 26VDC Note: Scope probes connected at machine output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...

  • Page 68: Typical Output Voltage Waveform-Machine Loaded Dc Stick Mode

    2 milliseconds in time. The machine was loaded with a resistance grid bank. The grid load meters read 150 amps and 26VDC Note: Scope probes connected at machine output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...
  • Page 69 50 Coupling .........DC volts and that each horizontal division repre- Trigger ........Internal sents 2 milliseconds in time. Note: Scope probes connected at machine output terminals: (+) probe to electrode, (–) probe to work. SQUARE WAVE TIG 175...
  • Page 70 F-38 F-38 NOTES SQUARE WAVE TIG 175...

  • Page 71: Scr Bridge Assembly Removal And Replacement

    SCR BRIDGE ASSEMBLY REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 72 5. With the 5/16” nutdriver remove the assembly. See Figure F.8 . three screws holding the case back to the internal divider panel. See Figure F.7. REAR PANEL MOUNTING SCREWS FIGURE F.7 CASE BACK MOUNTING SCREWS SQUARE WAVE TIG 175...
  • Page 73 AC SCR heat sink. sleeving. 17. Using the 7/16” wrench remove the Note placement of sleeving and cable positive lead from the right side ties for reassembly. positive heat sink. SQUARE WAVE TIG 175...
  • Page 74 SCR BRIDGE ASSEMBLY REMOVAL AND REPLACEMENT (continued) PLUG J1 REMOVED G2986-[ ] S-W TIG 175 CONTROL FIGURE F.9 PLUG J1 ON CONTROL BOARD PLUG J1 DIODE PIGTAIL CONNECTION FIGURE F.10 DIODE PIGTAIL CONNECTION TO POLARITY SWITCH LEAD. SQUARE WAVE TIG 175...
  • Page 75 8. Assemble the diode pigtail lead to the polarity switch lead. See Figure F.10 . Be sure to replace sleeving and secure with cable ties. Position with harness and secure with cable ties. SQUARE WAVE TIG 175...
  • Page 76 F-44 F-44 NOTES SQUARE WAVE TIG 175...

  • Page 77: Polarity Switch Removal And Replacement

    POLARITY SWITCH REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 78 See wiring diagram. Label lead and connection point for reassem- bly. 11. Using the 1/2” wrench remove the flat copper lead from the polarity switch. This lead connects to the high frequency transformer coil and the by-pass board. See wiring SQUARE WAVE TIG 175...
  • Page 79 7. Assemble the flex lead from diode D1 to the rear gang of the polarity switch. Make certain washers are in place and the nut is tight. SQUARE WAVE TIG 175...
  • Page 80 F-48 F-48 NOTES SQUARE WAVE TIG 175...

  • Page 81: High Voltage Transformer Removal And Replacement

    HIGH VOLTAGE TRANSFORMER REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 82 5. Remove the lead splice from the other primay lead that is connected to lead #237 and the C4 capacitor. See wiring diagram. Cut any necessary cable ties. TRANSFORMER SECONDARY LEADS FIGURE F.11 SECONDARY LEADS AT HIGH FREQUENCY STARTER BOARD SQUARE WAVE TIG 175...
  • Page 83 5. Reconnect the two secondary leads to the high frequency arc starter board assembly. SLOTTED REAR MOUNTING INSULATORS NOTE: On some machines the mounting screw configuration may be FRONT MOUNTING different. INSULATOR FIGURE F.12 HIGH VOLTAGE TRANSFORMER MOUNTING INSULATORS SQUARE WAVE TIG 175...
  • Page 84 F-52 F-52 NOTES SQUARE WAVE TIG 175...
  • Page 85 REMOVAL AND REPLACEMENT WARNING Service and repair should be performed only by Lincoln Electric factory trained per- sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau- tions detailed throughout this manual.
  • Page 86 8. Remove plug J3 from the control board and push through the interior divider panel. 9. Using the 1/2” wrench remove the choke lead from the polarity switch. See wiring diagram. Label lead and connection point for reassembly. SQUARE WAVE TIG 175...
  • Page 87 B230 and B232 to the main transformer leads. See wiring dia- gram. Insulate connections. 11. Replace any previously removed cable ties. Clear leads and check for “shorts” or “grounds”. 12. Perform Bridge Assembly Replacement Procedure . SQUARE WAVE TIG 175...
  • Page 88 F-56 F-56 NOTES SQUARE WAVE TIG 175...

  • Page 89: Retest After Repair

    RECOMMENDED METERS FOR MACHINE OUTPUT TESTS VOLTMETER: AC and DC True RMS Meter - Fluke 8922A or equivalent AMMETER: Columbia Type AX AC or DC Tong Ammeter IMPORTANT: IF OTHER TYPE METERS ARE USED RESULTS MAY NOT BE ACCURATE. SQUARE WAVE TIG 175...
  • Page 90 F-58 F-58 NOTES SQUARE WAVE TIG 175...
  • Page 91 Control PC Board (G2986) Schematic Part 1 of 2..... G-5 Control PC Board (G2986) Schematic Part 2 of 2..... G-6 SQUARE WAVE TIG 175...
  • Page 92 NOTES SQUARE WAVE TIG 175...
  • Page 93 ELECTRICAL DIAGRAMS Wiring Diagram WIRING DIAGRAM - SQUARE WAVE TIG 175 (208/ 230/ 1/ 60) H3 (230V) VOLTAGE RECONNECTION H2 (208V) 230 VOLT CONNECTION (AS SHOWN) H1 and H3 TO POWER SWITCH. R 209 W X3 H2 NOT CONNECTED; INSULATE.
  • Page 94 C1 AND C2 MUST ALWAYS BE ELECTRODE WORK ELECTRICAL SYMBOLS PER E1537. CONNECTED ACROSS POWER SWITCH. 7-12-96 L10059 NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. SQUARE WAVE TIG 175...
  • Page 95 NOTE: 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 SQUARE WAVE TIG 175 in danger to the Machine Operator or Technician.
  • Page 96 NOTE: 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 97 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. Improper PC board repairs could result in damage to the machine.
  • Page 98 Please include the machine’s code number and how the problem was resolved. Thank You, Technical Services Group Lincoln Electric Co. 22801 ST. Clair Ave. Cleveland, Ohio 44117-1199 FAX 216-481-2309 SVM Number ___________________________...

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