Lincoln Electric SQUARE WAVE SVM141-A Service Manual Download

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TROUBLESHOOTING & REPAIR

F-48

SQUARE WAVE TIG 275

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SCR BRIDGE ASSEMBLY REMOVAL AND REPLACEMENT

(continued)

REPLACEMENT PROCEDURE

Refer to Figures F.11 - F.13.

1. Carefully place the new SCR bridge assembly

in position in the TIG 275.

2. Using the 3/8” wrench, install the four mount-

ing screws.

Use Penetrox A13 joint compound on all alu-
minum connections.

3. Assemble lead “B” onto the AC left heat sink.

4. Assemble the shunt to the right side negative

heat sink.

5. Assemble the X2 transformer secondary lead

onto the right side heat sink.

6. Feed the J1 plug and harness through the

internal divider and install the plug into the
control board.

7. Assembly the “NEG” lead to the D1 diode pig-

tail. Replace and secure sleeve insulation.

8. Assemble the “POS” lead to the left side heat

sink.

9. Carefully position the fan motor assembly into

place.

10. Attach the fan motor assembly onto the glas-

tic divider using the three screws previously
removed.

11. Carefully position the case back into place,

being careful not to disconnect the leads
from the circuit breaker or receptacle.

12. Secure the case back with the nine screws

previously removed.

13. Assemble the case sides and top.

Summary of Contents for SQUARE WAVE SVM141-A

Page 1: ...portantly think before you act and be careful SERVICE MANUAL For use with machine code numbers 10523 10525 Square Wave TIG 275 Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC View Safety Info View Safety Info View Safety Info View Safety Info RETURN TO MAIN INDEX SQUARE WAVE TIG 275 Sales and Service through Subsidiaries and Distributors Worldwide Cleveland Ohio...

Page 2: ...HEIR DOCTOR BEFORE OPERATING Read and understand the following safety highlights For additional safety information it is strongly recommended that you purchase a copy of Safety in Welding Cutting ANSI Standard Z49 1 from the American Welding Society P O Box 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 C...

Page 3: ...the electrode holder work clamp welding cable and welding machine in good safe operating condition Replace damaged insulation 3 g Never dip the electrode in water for cooling 3 h Never simultaneously touch electrically hot parts of electrode holders connected to two welders because voltage between the two can be the total of the open circuit voltage of both welders 3 i When working above floor lev...

Page 4: ...arting a fire Remember that welding sparks and hot materials from welding can easily go through small cracks and openings to adjacent areas Avoid welding near hydraulic lines Have a fire extinguisher readily available 6 b Where compressed gases are to be used at the job site special precautions should be used to prevent hazardous situations Refer to Safety in Welding and Cutting ANSI Standard Z49 ...

Page 5: ...uttes de laitier en fusion sont émises de l arc de soudage Se protéger avec des vêtements de protection libres de l huile tels que les gants en cuir chemise épaisse pan 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 6 Eloigner les matériaux inflammables ...

Page 6: ...5 Welding Operation B 6 Stick Welding B 9 Auxiliary Power B 9 Accessories Section C Maintenance Section D Safety Precautions D 2 Routine and Periodic Maintenance D 2 Overload Protection D 2 Fan As Needed F A N D 2 Service Procedures D 2 Component Location and Access D 3 Spark Gap Adjustment D 3 Theory of Operation Section E General Description E 2 Input Power Circuit E 2 Output Rectification Contr...

Page 7: ...nmental Rating A 3 Machine Grounding and High Frequency Interference Protection A 3 Input Supply Connections A 4 Input Reconnect Procedure A 5 User Supplied Connectors A 6 Output Connections A 6 Work Cable Connection A 6 TIG Torch Connection A 7 Twist Mate Adapter for LA 9 and LA 17 TIG Torch A 8 Twist Mate Adapter for LW 18 and LW 20 TIG Torch A 8 Stick Electrode Cable Connection A 9 Return to Ma...

Page 8: ...bient 3 25 0 mm2 3 25 0 mm2 8 8 4 mm2 8 8 4 mm2 Input Amperes 130 120 61 49 Height Width Depth Weight Power 24 06 in 19 15 in 28 00 in Approx 330 lbs Source 611 mm 486 mm 711 mm 150 kg Lift Hook add 3 57 91 mm Power Source 33 40 in 27 65 in 40 65 in Approx 375 lbs on 848 mm 702 mm 1033 mm 170 kg Undercarriage PHYSICAL DIMENSIONS Fuse Super Lag or Breaker Size 1 150 150 70 60 1 Also called inverse ...

Page 9: ... not followed ENVIRONMENTAL RATING The Square Wave TIG 275 power source carries an IP21S environmental rating It may be used in normal industrial and commercial environments It is rated for use in damp dirty rain sheltered environments MACHINE GROUNDING AND HIGH FRE QUENCY INTERFERENCE PROTECTION The frame of the welder must be grounded A ground screw marked with the symbol is located at the right...

Page 10: ... electrical conductors within 50 ft 15 2m of the welder should be enclosed in grounded rigid metal lic conduit or equivalent shielding Flexible helical ly wrapped metallic conduit is generally not suit able 8 When the welder is enclosed in a metal building the metal building should be connected to several good earth driven electrical grounds as in 5 b above around the periphery of the building Fai...

Page 11: ...MPLE On a 208 230 460 volt welder LOW is 208V MID is 230V and HIGH is 460V Make sure all connections are tight Replace the case side and all screws INSTALLATION A 5 A 5 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC FIGURE A 2 RECONNECT PANEL INSTRUCTIONS...

Page 12: ...cable Skin the cable jacket to 1 50 in 38 1 mm for a 2 0 thru 3 0 70 thru 95 mm2 cable 2 If necessary trim the cable end of the rubber boot to match the diameter of the cable 3 Slide the rubber boot onto the skinned cable end Use soap for lubricant if required 4 Slide the copper tube into the brass plug Insert skinned cable into the copper tube 5 Tighten set screw s to collapse copper tube Screw s...

Page 13: ...failure The optional water solenoid valve may also malfunction When the water solenoid valve option is installed into the Square Wave TIG 275 connect the coolant supply line from either cooler outlet or single pass supply to the Water Inlet fitting located on the machine s case front Connect the TIG torch s smaller water fitting to the Water Out fitting also located on the case front A non metalli...

Page 14: ...and LW 20 TIG TORCH The Twist Mate connection allows fast and reliable TIG torch connections to the electrode terminal of the Square Wave TIG 275 The Twist Mate adapter and strain relief boot needed to connect an LW 18 or LW 20 torch or any equivalent water cooled TIG torch with the fittings shown in the diagrams under step 2 and 3 are included with the Square Wave TIG 275 Assemble the the LW 18 o...

Page 15: ... source For more details see M19116PRINT included with the machine STICK ELECTRODE CABLE CONNECTION The Twist Mate connection allows fast and reliable stick electrode attachment to the electrode terminal of the Square Wave TIG 275 welding power supply Assemble the electrode cable by attaching the correct Twist Mate adapter and electrode holder to an ade quately sized welding cable See Table A 1 an...

Page 16: ...ES A 10 A 10 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 17: ...ttings B 5 Welding Operation B 6 TIG Welding B 6 TIG Welding Guidelines B 6 TIG Welding Sequence of Operation 2 Step TIG Mode B 7 TIG Welding Sequence of Operation 4 Step TIG Mode B 7 Hand and Foot Amptrol Operation B 8 Advanced TIG Welding Features B 8 AC Wave Balance and Auto Balance B 8 Stick Welding B 9 Auxiliary Power B 9 60 Hertz Domestic Machines B 9 50 60 Hertz European Machines B 9 Return...

Page 18: ... in the Safety section if welding must be per formed under electrically hazardous condi tions such as welding in wet areas or on or in the workpiece FUMES AND GASES can be dangerous Keep your head out of fumes Use ventilation or exhaust to remove fumes from breathing zone WELDING SPARKS can cause fire or explosion Keep flammable material away Do not weld on containers that have held combustibles A...

Page 19: ...and nuisance shut downs 2 STEP 4 STEP TIG STICK mode control switch 4 STEP mode requires the use of an optional Arc Start Switch This welding mode reduces fatigue by elimi nating the need to manually control the weld current during the weld Down Slope Time control is active in 4 STEP TIG mode It controls the amount of time approximately 1 to 10 seconds it takes the weld current to ramp down from t...

Page 20: ...opean Schuko type Receptacle with 2 Amp Circuit Breaker European Model Only Low Voltage Trigger Circuit 18 VAC for maximum operator safety Remote Receptacle for Amptrol or Arc Start Switch connection Gas Valve Inlet fitting conforms to Compressed Gas Association CGA standards WELDING CAPABILITY The Square Wave TIG 275 is rated at 275 amps 31 volts at 40 duty cycle on a ten minute basis for DC TIG ...

Page 21: ... is active in 4 Step TIG mode only It adjusts the time from 0 5 to 10 seconds the welding output takes to ramp down from the preset level to 25 of that level 5 2 Step 4 Step TIG Stick Mode Control Switch This switch selects the welding mode desired TIG 2 Step TIG 4 Step or Stick Read the complete Operating Instructions section for more information on TIG 2 Step and TIG 4 Step 6 Trimmer Potentiomet...

Page 22: ...ctrode sizes stickouts currents cup or nozzle sizes are shown in Table B 1 SINCE WELDING APPLICATIONS CAN VARY THIS CHART IS INTENDED AS A GUIDE ONLY OPERATION B 6 B 6 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC 1 When used with argon gas The current r...

Page 23: ... solenoid valves will close To make another weld repeats steps 9 and 10 TIG WELDING SEQUENCE OF OPERATION 4 Step TIG Mode 1 Connect an Arc Start Switch to the Remote Amphenol 2 Turn the welder gas supply and water supply if so equipped on The digital ammeter voltmeter dis play will illuminate when the power is on 3 Select the 4 Step TIG Mode with the 2 Step 4 Step TIG Stick switch 4 Set the maximu...

Page 24: ...is near the tungsten operating range In the example above a 3 32 tungsten may be used on DC to weld near 200 amps To start the weld the operator may have to depress the Amptrol approxi mately 1 4 of the way down or to nearly 50 amps in order to start the arc Merely depressing the Amptrol to its 5 amp minimum position will not start the arc ADVANCED TIG WELDING FEATURES AC WAVE BALANCE AND AUTO BAL...

Page 25: ...are sig nificantly higher than their running current These high er starting currents may cause the circuit breaker to open If this situation occurs the user should refrain from using the Square Wave TIG 275 auxiliary for that equipment 50 60 HERTZ EUROPEAN MACHINES The Square Wave TIG 275 machines rated for 50 60Hz operation provides 2 amps of 220 volt AC power at a continental European Schuko typ...

Page 26: ...ES B 10 B 10 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 27: ...CESSORIES Accessories Section C Accessories Included with Machine C 2 Optional Accessories C 2 Section C 1 Section C 1 SQUARE WAVE TIG 275 Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 28: ...52 95 Twist Mate Cable Plug for 2 0 to 3 0 Work Lead K932 1 Undercarriage When the undercarriage is properly installed the Square Wave TIG 275 lift bail is nonfunctional Do not attempt to lift the power source with the undercarriage attached THe undercarriage is desinged for hand moving only mechanized towing can lead to personal injury and or damage to the Square Wave TIG 275 K1622 1 Twist Mate A...

Page 29: ...E SECTION Maintenance Section D Safety Precautions D 2 Routine and Periodic Maintenance D 2 Overload Protection D 2 Fan As Needed F A N D 2 Service Procedures D 2 Component Location and Access D 3 Control PC Board D 3 Display PC Board Arc Starter Bypass PC Board D 3 Spark Gap Assembly High Voltage Transformer D 3 Main Rectifier D 3 Spark Gap Adjustment D 3 ...

Page 30: ...ontinue to run to cool the power source No welding is possible until the machine is allowed to cool and the Thermostatic Protection Light goes out FAN AS NEEDED F A N The Square Wave TIG 275 has the F A N circuit fea ture which means the cooling fan will operate only while welding then for about 6 minutes after welding has stopped The cooling fan will operate conintuous ly if the yellow Thermstati...

Page 31: ...unted to the main transformer in front of the cooling fan SPARK GAP ADJUSTMENT The spark gap is set at the factory to a gap of 0 015 inches 0 4 mm This setting is adequate for most applications Where less high frequency is desired the setting can be reduced to 0 008 inches 0 2 mm To adjust the spark first be sure that the input power to the machine is OFF AT THE DISCONNECT SWITCH OR FUSE BOX The h...

Page 32: ...TOC Return to Master TOC 4 3 5 12 11 2 1 9 8 13 10 7 6 SQUARE WAVE TIG 275 FIGURE D 2 MAJOR COMPONENT LOCATIONS 1 CASE FRONT WITH DISPLAY BOARD 2 INTERNAL DIVIDER WITH CONTROL BOARD 3 CASE SIDES 4 CASE TOP 5 CASE BACK 6 FAN MOTOR ASSEMBLY 7 RECONNECT PANEL 8 BASE 9 HIGH VOLTAGE TRANSFORMER 10 MAIN TRANSFORMER 11 CHOKE 12 OUTPUT RECTIFIER BRIDGE 13 HIGH FREQUENCY UNIT SPARK GAP ASSEMBLY ...

Page 33: ...utput E 6 SCR Operation E 7 Protective Circuits E 8 Thermal Protection E 8 Overload Protection E 8 INPUT POWER SWITCH MAIN TRANSFORMER POLARITY SWITCH SCR BRIDGE X1 X2 AC AC DC DC CONTROL BOARD 18VAC 18VAC 115VAC FAN REMOTE RECEPTACLE H1 H2 H3 SHUNT 115VAC HIGH VOLTAGE TRANSFORMER CIRCUIT BY PASS BOARD HI FREQUENCY TRANSFORMER C H O K E WORK ELECTRODE THERMAL LIGHT GAS VALVE OUTPUT CONTROL MODE SW...

Page 34: ...gh current out put available at the main secondary winding X1 and X2 This 78 VAC winding supplies power to the weld ing arc In addition four auxiliary windings are incor porated in the main transformer The 115 VAC winding supplies power to the 115 VAC receptacle Through the control board it also powers the gas solenoid the high voltage transformer and the cooling fan The cooling fan is activated o...

Page 35: ...res them to the feedback information received from the shunt and sends the appropriate gate firing signals to the output SCR bridge The control board regulates the firings of the output SCRs which control the output of the machine See SCR Operation The control board also monitors the ther mostats and controls the gas solenoid the thermal light and the cooling fan THEORY OF OPERATION E 3 E 3 SQUARE...

Page 36: ...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 Diagram are the subject of discussion FIGURE E 4 HIGH VOLTAGE HIGH FREQUENCY CIRCUIT INPUT POWER SWITCH MAIN TRANSFORMER POLARITY SWITCH SCR BRIDGE X1 X2 AC AC DC DC CONTROL BOARD 18VAC 18VAC 115VAC FAN REMOTE RECEPTACLE H1 H2 H3 SHUNT 115...

Page 37: ... configuration resulting in a controlled DC output Since the choke is in series with the nega tive leg of the bridge and also in series with the weld ing load a filtered DC is applied to the output terminals The bypass board protects the internal circuitry from interference INPUT POWER SWITCH MAIN TRANSFORMER POLARITY SWITCH SCR BRIDGE X1 X2 AC AC DC DC CONTROL BOARD 18VAC 18VAC 115VAC FAN REMOTE ...

Page 38: ...he out put terminals THEORY OF OPERATION E 6 E 6 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC FIGURE E 7 AC WELDING OUTPUT FIGURE E 8 AC SQUARE WAVE WELDING CURRENT GENERATION INPUT POWER SWITCH MAIN TRANSFORMER POLARITY SWITCH SCR BRIDGE X1 X2 AC AC DC...

Page 39: ...e This gate pulse must be more positive than the cath ode voltage Since there is a standard PN junction between gate and cathode the voltage between these terminals must be slightly greater than 0 6V Once the SCR has fired it is not necessary to continue the flow of gate current As long as current continues to flow from anode to cathode the SCR will remain on When the anode to cathode current drop...

Page 40: ... to run and welding output will be disabled Once the machine cools sufficiently the thermostats are self resetting If the shutdown is caused by excessive output or duty cycle and the fan is operating normally the power may be left on and the reset should occur within a 15 minute period If the fan is not functioning properly or the air intake louvers are obstructed the input power must be removed a...

Page 41: ...al Open Circuit Voltage Waveform DC TIG Mode F 34 Normal Open Circuit Voltage Waveform AC Stick Mode F 35 Normal Open Circuit Voltage Waveform DC Stick Mode F 36 Typical Output Voltage Waveform Machine Loaded AC TIG Mode F 37 Typical Output Voltage Waveform Machine Loaded DC TIG Mode F 38 Typical Output Voltage Waveform Machine Loaded AC Stick Mode F 39 Typical Output Voltage Waveform Machine Load...

Page 42: ...y contribute to the machine symptom Perform these tests checks in the order listed In general these tests can be con ducted without removing the case wrap around cover Step 3 RECOMMENDED COURSE OF ACTION The last column labeled Recommended Course of Action lists the most likely components that may have failed in your machine It also specifies the appropriate test procedure to verify that the subje...

Page 43: ...PC Board from the static shielding bag and place it directly into the equipment Don t set the PC Board on or near paper plastic or cloth which could have a static charge If the PC Board can t be installed immediately put it back in the static shielding bag If the PC Board uses protective shorting jumpers don t remove them until installation is complete If you return a PC Board to The Lincoln Elect...

Page 44: ...ce before you proceed Call 216 383 2531 or 1 800 833 9353 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION OUTPUT PROBLEMS The machine is dead No weld out put no 115 VAC at the receptacle 220 VAC receptacle on European models only 1 Check the input voltage The input voltage must match the rating plate and the voltage con nection Refer to Reconnect Procedure in the I...

Page 45: ...welding output The 115 VAC is present at the receptacle 220 VAC receptacle on European mod els only 1 Make sure the polarity switch is in the proper position and func tioning correctly 2 One of the thermostats may be tripped Allow the machine to cool The thermal light will be on 3 Make sure the welding cables torch and connections are in good operating condition 1 Check for loose or faulty con nec...

Page 46: ... the unit until the ther mal light is off 2 The air louvers may be blocked Remove the air obstruction and allow the unit to cool 1 One of the thermostats may be faulty Check or replace See the Wiring Diagram 2 Check for loose or faulty wires on the thermostats and associ ated circuitry See the Wiring Diagram 3 The fan motor may be faulty or mechanically obstructed The fan should run when welding o...

Page 47: ...e operates correctly in the TIG mode 1 Check the electrode cable and holder for loose or faulty con nections 2 Make sure the Stick TIG switch S3 is in the proper position and operating correctly 1 Check the Stick TIG switch S3 and associated leads See the Wiring Diagram 2 The control board may be faulty The machine welds at a very low output regardless of the current control setting 1 If welding i...

Page 48: ...ss of the current control setting 1 If welding in the TIG mode the remote control device may be defective 1 Perform the SCR Bridge Test 2 Perform the T1 Transformer Test 3 Check the current control for proper operation Normal resis tance is 10 000 ohms See the Wiring Diagram 4 Check leads 221 and 222 between the output shunt and the control board See the Wiring Diagram 5 The control board may be f...

Page 49: ...Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 216 383 2531 or 1 800 833 9353 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION OUTPUT PROBLEMS The machine makes a very loud buzzing noise in DC Stick or in DC TIG modes There is no current draw from the machine s output ter minals The machine is not exter nally lo...

Page 50: ... sure that the machine is grounded properly according to the installation instructions If there are other high frequency sources in the area make cer tain that they are grounded properly 2 Make sure the Amptrol is oper ating properly 3 Check to make sure that the input voltage is correct for the machine to reconnect configura tion Refer to Reconnect Procedure in the Installation section of this ma...

Page 51: ...NT S RECOMMENDED COURSE OF ACTION TIG WELDING PROBLEMS No high frequency The machine is in the TIG mode and has normal output 1 If the machine is in a highly dirty environment with conductive contaminants check and clean the spark gap with a low pres sure air stream per the mainte nance instructions 2 Check the spark gap operation and setting Normal is 0 015 Refer to the Maintenance Section of thi...

Page 52: ... 2531 or 1 800 833 9353 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION TIG WELDING PROBLEMS The high frequency spark is pre sent but weak 1 The spark gap may be too large Check and reset per instructions in the Maintenance Section of this manual 2 The work and or torch cables may be in poor condition allow ing the high frequency to lead to ground Use good quality ...

Page 53: ...e machine has normal open circuit voltage Refer to Technical Specifications in the Installation section 1 The torch may be faulty Check or replace 2 The current control may be set too low 3 The tungsten electrode may be contaminated Replace or sharpen 4 The electrode may be too large for the process 5 If a helium blend is being used as a shielding gas reduce the percentage of helium 6 Check the we...

Page 54: ...00 833 9353 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION STICK WELDING PROBLEMS The stick electrode blasts off when touched to the work piece 1 The welding current may be too high for the electrode size Reduce current control setting or use a larger diameter elec trode 1 Perform the SCR Bridge Test 2 The control board may be faulty Variable or sluggish welding a...

Page 55: ...tivated and or the welding arc is estab lished The voltmeter will nor mally display open circuit volt age in the Stick mode before the arc is established 1 Check the connections and associated leads between the display board and the control board Plugs P4 P20 and P21 See the Wiring Diagram 2 The display board may be faulty 3 The control board may be faulty The voltmeter always reads 000 but the we...

Page 56: ...act the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 216 383 2531 or 1 800 833 9353 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION FUNCTION PROBLEMS The ammeter display reads 000 The machine has output but no control 1 None 1 Check leads 221 and 222 between the output shunt and plug J2 on the control board S...

Page 57: ...he 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 216 383 2531 or 1 800 833 9353 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION FUNCTION PROBLEMS The AC wave balance control does not function properly 1 The AC wave balance control is...

Page 58: ...electrical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical trou bleshooting assistance before you proceed Call 216 383 2531 or 1 800 833 9353 WELD TEST DESCRIPTION This procedure will disabl...

Page 59: ...er to the TIG 275 machine 2 Using the 3 8 nut driver remove the right side case cover 3 Locate the Spark Gap Assembly at the lower right side of the machine See Figure F 1 4 Carefully remove the two leads and washers from the Spark Gap Assembly 5 Insulate the leads from each other and from the case When power is applied to the machine there is a very high voltage present at these leads 6 When volt...

Page 60: ...to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531 or 1 800 833 9353 WELD TEST DESCRIPTION This test will d...

Page 61: ...AD 204 PIN 13 LEAD 211A G3360 TEST PROCEDURE 1 Remove main supply power to the machine 2 Using the 3 8 nut driver remove the case left and right side covers 3 Locate plug J8 on the control board See Figure F 2 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 4 Carefully apply the correct input power mak ...

Page 62: ...s functioning properly a If all of the secondary voltages are missing or incorrect make certain that the correct input voltage is being applied to the correct primary leads See Table F 1 b If the correct input voltage is being applied to the primary leads and any or all of the secondary voltages are incorrect the T1 transformer may be faulty See Main Transformer and Output Choke Removal and Replac...

Page 63: ...DARY WINDINGS SECONDARY VOLTAGES PLUG J8 PIN 1 LEAD 210 TO PLUG J8 PIN 9 LEAD 209 18 VAC PLUG J8 PIN 6 LEAD 201 TO PLUG J8 PIN 4 LEAD 204 18 VAC PLUG J8 PIN 2 LEAD 231 TO PLUG J8 PIN 12 LEAD 232A 115 VAC PLUG J8 PIN 13 LEAD 211A TO PLUG J8 PIN 14 LEAD 212 23 VAC X1 TO X2 78 VAC PRIMARY WINDINGS1 PRIMARY VOLTAGES H1 TO H2 208 VAC H1 TO H3 230 VAC H1 TO H4 460 VAC NOTE If the input voltages vary the...

Page 64: ...anty For your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531 or 1 800 833 9353 WELD TEST DES...

Page 65: ...r to the TIG 275 7 Activate the torch trigger and check for approximately 115 VAC at the solenoid leads 234 and 235 If the correct volt age is present the solenoid should activate and gas should flow 8 If voltage is present at leads 234 and 235 and the solenoid does not activate the solenoid may be defective The solenoid can be further checked by removing leads 234 and 235 from the solenoid and ap...

Page 66: ... and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531 or 1 800 833 9353 WELD TEST DESCRIPTION The Static ...

Page 67: ...ter TOC Return to Master TOC TROUBLESHOOTING REPAIR F 27 F 27 SQUARE WAVE TIG 275 STATIC SCR TEST continued FIGURE F 4 PLUG J1 LOCATION ON CONTROL BOARD S W TIG 275 CONTROL G3360 J1 J8 TEST PROCEDURE 1 Remove main supply power to the TIG 275 and remove the case top and left side 2 Locate and remove plug J1 from the control board See Figure F 4 ...

Page 68: ...nd check from cathode to anode of SCR1 See Figure F 5 If a low resistance is indicated in either direction SCR1 is faulty Replace the SCR Bridge Assembly See SCR Bridge Assembly Removal and Replacement 4 Repeat Step 3 testing SCR2 SCR3 and SCR4 5 To further check the SCR s functions use an SCR tester and proceed to the Active SCR Test NOTE Also check diode D1 6 Replace plug J1 on the control board...

Page 69: ...y warranty For your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531 or 1 800 833 9353 WELD DE...

Page 70: ... G3360 J1 J8 TEST PROCEDURE 1 Remove main supply power to the TIG 275 machine 2 Locate and remove plug J1 from the control board See Figure F 6 3 Perform the following test for all four SCRs See Figure F 8 4 Construct the circuit outlined in Figure F 7 One 6V lantern battery can be used Resistor values are 10 The voltmeter scale should be low approximately 0 5 or 0 10 volts 5 Battery Test Check th...

Page 71: ...rn to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ACTIVE SCR TEST continued FIGURE F 7 ACTIVE SCR TEST SETUP R2 SW2 SW1 V R1 6volt Lantern Battery A G C SCR under test R1 4 ohms 10 watts R2 3 ohms 10 watts Resistor valves are 10 ...

Page 72: ...eads higher than zero the SCR is shorted 8 With switch SW 1 closed close switch SW 2 for two seconds and release The voltmeter should read 3 to 6 volts before and after switch SW 2 is released If the voltmeter does not read or reads only while SW 2 is depressed the SCR or battery is defective Repeat Battery Test Procedure described in Step 5 9 Open switch SW 1 disconnect the gate lead G and revers...

Page 73: ...epresents 50 volts and that each horizontal division rep resents 2 milliseconds in time NOTE Scope probes connected at machine output terminals probe to electrode probe to work NOTE AC balance control set at Balanced position SCOPE SETTINGS Volts Div 50 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM AC TIG MODE 0 V 50 V 2 ms CAUTION HIGH VOLTAGE H...

Page 74: ...t each vertical division represents 50 volts and that each horizontal division represents 2 milliseconds in time NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 50 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal NORMAL OPEN CIRCUIT VOLTAGE WAVEFORM DC TIG MODE 0 V 2 ms 50 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage...

Page 75: ...ach vertical division represents 50 volts and that each horizontal division rep resents 2 milliseconds in time NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 50 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal 0 V 2 ms 50 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all voltage and waveform ch...

Page 76: ...erated from a prop erly operating machine Note that each vertical division represents 50 volts and that each horizontal division represents 2 milliseconds in time NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 50 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal 0 V 2 ms 50 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damag...

Page 77: ...ting machine Note that each vertical division represents 20 volts and that each horizontal division rep resents 2 milliseconds in time The machine was loaded with a resistance grid bank NOTE Scope probes connected at machine output terminals probe to electrode probe to work NOTE AC balance control set at Balanced position SCOPE SETTINGS Volts Div 20 V Div Horizontal Sweep 2 ms Div Coupling DC Trig...

Page 78: ...cal division represents 20 volts and that each horizontal division represents 2 milliseconds in time The machine was loaded with a resistance grid bank NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 20 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal 0 V 2 ms 20 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equi...

Page 79: ... division represents 20 volts and that each horizontal division rep resents 2 milliseconds in time The machine was loaded with a resistance grid bank NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 20 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal 0 V 2 ms 20 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipm...

Page 80: ... division represents 20 volts and that each horizontal division rep resents 2 milliseconds in time The machine was loaded with a resistance grid bank NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 20 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal 0 V 2 ms 20 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equipm...

Page 81: ... or non functioning output SCR Note that each vertical division represents 50 volts and that each horizontal division represents 2 milliseconds in time NOTE Scope probes connected at machine output terminals probe to electrode probe to work SCOPE SETTINGS Volts Div 50 V Div Horizontal Sweep 2 ms Div Coupling DC Trigger Internal 0 V 2 ms 50 V CAUTION HIGH VOLTAGE HIGH FREQUENCY can damage test equi...

Page 82: ...will invalidate your factory warranty For your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 253...

Page 83: ...se pliers remove the two secondary leads from the quick connects on the high frequency arc starter board assem bly See Figure F 9 4 Disconnect the in line splice quick connect from one primary lead to lead 238 Cut any necessary cable ties 5 Remove the lead splice from the other prima ry lead that is connected to lead 237 C6 capacitor and R5 resistor See the Wiring Diagram Cut any necessary cable t...

Page 84: ... INSULATOR SLOTTED REAR MOUNTING INSULATORS REPLACEMENT PROCEDURE 1 Carefully position the new high voltage trans former in place in the two rear mounting insu lators See Figure F 10 2 Install the front mounting insulator and mount ing screw 3 Using the phillips head screw driver tighten all three mounting screws making certain the insulators are positioned correctly 4 Reconnect the two primary le...

Page 85: ...factory warranty For your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531 or 1 800 833 9353 W...

Page 86: ...8 nut driver remove the case sides and top 3 Using the 3 8 nut driver remove the nine screws from the case back 4 Carefully remove the case back and set aside NOTE The receptacle and circuit breaker leads will still be attached See Figure F 11 5 With the 3 8 nut driver remove the three screws mounting the fan motor bracket assembly to the internal glastic divider panel See Figure F 12 6 Carefully ...

Page 87: ... the D1 diode pigtail NOTE It will be necessary to remove the sleeve insulation to gain access to the con nection 9 Remove plug J1 from the control board Also remove the plug and lead harness from the internal divider panel 10 With the 1 2 wrench remove the X2 trans former secondary lead from the right side heat sink assembly It is not necessary to remove the jumper lead or the 216 lead 11 With th...

Page 88: ...sink 4 Assemble the shunt to the right side negative heat sink 5 Assemble the X2 transformer secondary lead onto the right side heat sink 6 Feed the J1 plug and harness through the internal divider and install the plug into the control board 7 Assembly the NEG lead to the D1 diode pig tail Replace and secure sleeve insulation 8 Assemble the POS lead to the left side heat sink 9 Carefully position ...

Page 89: ... your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531 or 1 800 833 9353 WELD DESCRIPTION This...

Page 90: ... PANEL CONTROL KNOBS OUTPUT CONTROL KNOB ALLEN SCREW NAMEPLATE POLARITY SWITCH HANDLE SCREW POLARITY SWITCH PROCEDURE 1 Remove the input power to the TIG 275 machine 2 Using the 3 8 nut driver remove the case sides and top For Steps 3 8 see Figure F 14 3 Using the 5 64 allen type wrench remove the output control knob 4 Using the phillips head screw driver remove the screw from the polarity switch ...

Page 91: ...turn to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC POLARITY SWITCH REMOVAL AND REPLACEMENT continued FIGURE F 15 POLARITY SWITCH CONNECTIONS 253 X1 MICRO SWITCH LEADS B POS NEG CHOKE ...

Page 92: ...31B 115VAC 232B B X3 W X8 W 204 18VAC R 210 B X9 W X7 W 201 18VAC W X10 W 209 H1 H2 208V H3 230V H4 460V S F S F 78VAC X1 X2 E F D B C B A X1 POS B FRONT GANG POLARITY SWITCH MICRO SWITCH AC A C D E B F OPEN DC B D C E A F G H CLOSED DC B D A E C F G H CLOSED REAR GANG MICRO SWITCH 312 275C NO NC D2 S2A H G NEG S2 POLARITY SWITCH REAR VIEW SHOWN IN AC POSITION POS SCR3 SCR4 D1 R7 X2 NEG G1 G2 218 ...

Page 93: ...e Wiring Diagram Label lead and connection point for reassembly Also remove lead 253 14 Using the 1 2 wrench remove the choke lead from the polarity switch See the Wiring Diagram Label lead and connection point for reassembly 15 With the 1 2 wrench remove the X1 sec ondary lead from the polarity switch See the Wiring Diagram Label lead and connection point for reassembly 16 Carefully unsolder the ...

Page 94: ...ill invalidate your factory warranty For your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshoot ing assistance before you proceed Call 216 383 2531...

Page 95: ...EDURE 1 Remove the input power to the TIG 275 machine 2 Perform the SCR Bridge Assembly Removal Procedure 3 Label and remove lead 232B from the circuit breaker located on the case back 4 Label and remove lead 231B from the recep tacle located on the case back 5 Remove Plug J8 from the control board See Figure F 17 6 Using the mini molex extraction tool remove the following six leads from plug J8 S...

Page 96: ...r reassembly 11 Using the 5 16 nut driver remove the one screw from the lower front corner of the glas tic reconnect panel 12 Remove the H1 capacitor lead from the capacitor terminal 13 Using the 5 16 nut driver remove the four screws from the glastic choke baffles 14 Remove the glastic reconnect panel by lifting up on the choke baffle and sliding the recon nect panel away from the machine Clear a...

Page 97: ...assembly from the choke lead 22 Carefully slide the panel away from the transformer about two inches 23 Remove the left side choke glastic baffle 24 Remove leads 314 and 316 from the choke thermostat See the Wiring Diagram 25 Remove lead 315 and 316 from the X1 secondary lead thermostat See the Wiring Diagram 26 Disconnect the primary thermostat lead splices 313 and 315 See the Wiring Diagram 27 W...

Page 98: ...y to the choke lead 4 Attach the lead side panel to the base with two screws 5 Attach the left side panel to the metal lift bail baffle 6 Connect the X1 transformer lead and the choke lead to the polarity switch 7 Connect the H1 primary lead to the input line switch 8 Fit the choke baffle and glastic reconnect panel together and attach them with screws 9 Attach the H1 capacitor lead to the capacit...

Page 99: ...IG MODE OCV AC 70 76 VAC DC 59 67 VDC MAXIMUM ACCEPTABLE OUTPUT VOLTAGE AT MINIMUM OUTPUT SETTINGS DC TIG Mode 5 Amps 13 Volts MINIMUM ACCEPTABLE OUTPUT VOLTAGE AT MAXIMUM OUTPUT SETTING DC TIG Mode 300 Amps 32 Volts 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 ...

Page 100: ...ES F 60 F 60 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

Page 101: ...ction Section G Wiring Diagram L10747 G 2 Wiring Diagram L10747 2 G 3 Control Board Schmatic G3358 1 G 4 Control Board Schmatic G3358 2 G 5 Display Board Schematic L10768 G 6 Bypass Board Schematic S22530 G 7 Display Board Layout L10770 1 G 8 Control Board Layout G3360 1 G 9 Bypass Board Layout L10121 1 G 10 TABLE OF CONTENTS ELECTRICAL DIAGRAMS SECTION ...

Page 102: ...231 209 235 238 234 212 204 201 236 261 247 211A 232A 220A H1 NC CLOSED CLOSED OPEN R1 277 J20 R4 276 J21 277A H2 W 209 18VAC X7 R 210 W 201 X8 L2 460 VOLT CONNECTION AS SHOWN CONNECT A TO HIGH H4 TO GROUND PER 230 VOLT CONNECTION CONNECT A TO MID H3 7 24 98 7 24 98 C L2 SV1 235A 234A F S BALANCE CONTROL X5 L4 C5 T2 F E D C X2 X1 T1 78VAC S W 204 A C D E B F B D C E A F G H G DC 211 DC C6 277B 245...

Page 103: ... B ROBOTIC INTERFACE CONNECTION CURRENT CONTROL L2 N C NOT PRESENT ON EARLIER PC BOARDS SV1 AMPTROL W R B B W H B W D H1 NC CLOSED CLOSED OPEN R1 277 J20 R4 276 J21 277A LOW NO 314 216 G4 217 H4 POS D FRONT GANG R2 BALANCE CONTROL X5 L4 C5 T2 F E D C X2 X1 T1 78VAC S W 204 A C D E B F B D C E A F G H G DC 211 DC C6 277B 245 254 J2 J1 255 AT MINIMUM D F J7 J8 PC BOARD T3 GAP SPARK L3 REMOTE X2 NEG ...

Page 104: ...D22 X6 4 5 6 Q13 2N4403 47 5 R104 GATE SCR 3 GATE SCR 1 41 SUPPLY J8 16 PIN J5 14 PIN J7A 8 PIN J7 8 PIN J4 10 PIN Q J2 4 PIN J1 8 PIN J3 4 PIN J6 4 PIN VOLTAGE NET FRAME CONNECTION POWER SUPPLY SOURCE POINT EARTH GROUND CONNECTION COMMON CONNECTION 637 99 39 17 4 OCI TRI DZ C LABELS X 6 LAST NO USED D R 818 Q17 2N4403 D G S 15A 60V Q8 3 1 2 10 0K R191 10 0 R158 10 0 R168 47 5 R96 J1 4 J1 6 47 5 R...

Page 105: ... 3043 OCI2 2 6 1 4 X11 1 2 3 150 R618 50V 0 1 C270 68 1K R23 3043 OCI3 2 6 1 4 1 00K R211 C100 CNY17 3 OCI5 4 2 1 6 5 X17 8 6 9 4 75K R585 400V 1 C84 C74 10 0K R179 D76 6 81K R542 C91 Q18 2N4401 GAS DRIVING CIRCUIT PULSER_PRESET 10 0K R584 3000V 0047 C88 4 7 35V C272 t 24 PTC2 Set control pot at max t 24 PTC5 50V 0 1 C152 t 24 PTC6 t 24 PTC4 39mH 1A L3 5W 10V DZ38 3 32K R472 39mH L4 15V 3000V 0047...

Page 106: ...8 VOLTS 53 D SUPPLY C LABELS EARTH GROUND CONNECTION R 128 POWER SUPPLY SOURCE POINT 12 LAST NO USED X VOLTAGE NET COMMON CONNECTION DZ 1 18 FRAME CONNECTION Vsp WORK 20 10 OE D1 Q5 Q6 LE Q7 Q4 Q3 Q2 Q1 Q0 Vcc GND D7 D5 D3 D4 D0 D2 D6 74HC373 X11 8 13 2 5 9 15 18 12 1 19 7 14 11 16 17 3 6 4 48 23 XTAL PA1 EXTAL PE1 PD2 XIRQ VRL IRQ IC1 PA2 RESET PD1 PD0 PA3 PA7 PE0 PE3 PE2 PD3 PD5 PD4 MODA Vss VRH...

Page 107: ... Graphic Graphic FRAME CONNECTION ARC STABILIZER CAPACITOR RESISTOR N A SHOW THE EXACT COMPONENTS COMMON CONNECTION AND SCREW TO STEEL STANDOFF ON MACHINE MFD 022 50V CAPACITORS UNLESS OTHERWISE SPECIFIED SINCE COMPONENTS OR CIRCUITRY ON RESISTORS Ohms POWER SUPPLY SOURCE POINT VOLTAGE NET 1A 400V CONTROLS HAVING A COMMON CONNECTION MADE THROUGH HOLE WITH SOLDER PAD HOLE WITH SOLDER PAD 80J 150V T...

Page 108: ...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 ...

Page 109: ...4 R542 R539 R499 R486 R485 R484 R483 R482 R481 R480 R477 R476 R474 R473 D79 C198 C200 C201 C204 C207 C231 C232 C233 D70 D72 D76 D77 D78 R34 C17 C183 DZ20 DZ21 DZ24 DZ22 DZ23 D64 DZ1 D46 D44 DZ4 D22 D21 D14 D20 DZ2 D45 D4 D54 D55 D36 D35 DZ9 DZ11 DZ14 C82 C103 C108 C104 C106 C99 C65 C158 C2 C180 C181 C197 C80 C66 C107 C95 C88 C190 C195 C196 D56 D57 D58 D59 D48 D50 D51 D52 D49 L2 L1 L5 L4 L6 L7 L8 O...

Page 110: ...s 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 Improper PC board repairs could result in damag...

Page 111: ...es G 11 G 11 SQUARE WAVE TIG 275 Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC ...

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