Lincoln Electric Precision TIG 375 Service Manual Download Page 143

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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 pro-

vided 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 damage to the

machine.

ELECTRICAL DIAGRAMS

G-31

PRECISION TIG 375

PC BOARD ASSEMBLY - TIG OPTION - ABOVE CODE 11000 (G4761-1)

UNLESS OTHERWISE SPECIFIED:

CAPACITANCE = MFD/VOLTS

INDUCTANCE = HENRIES

RESISTANCE = OHMS

G4761-1

INDUSTRIAL TIG

ADVANCED CONTROL PC BOARD ASSEMBLY

1:1

G4040

Jbarto

T Nguyen

UNLESS OTHERWISE SPECIFIED TOLERANCE

MANUFACTURING TOLERANCE PER E2056

ON 2 PLACE DECIMALS IS ± .02

ON 3 PLACE DECIMALS IS ± .002

ON ALL ANGLES IS ± .5 OF A DEGREE

WITH PUBLISHED STANDARDS.

MATERIAL TOLERANCE (" ") TO AGREE

DO NOT SCALE THIS DRAWING

DRAWN BY:

DESIGN INFORMATION

ENGINEER:

APPROVED:

REFERENCE:

EQUIPMENT TYPE:
SUBJECT:

SCALE:

MATERIAL

DISPOSITION:

APPROVAL

DATE:

PROJECT

NUMBER:

CRM38259

PAGE ___ OF ___

ENGINEERING CONTROLLED

MANUFACTURER:

DOCUMENT

NUMBER:

DOCUMENT

REVISION:

THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OWNED BY LINCOLN GLOBAL, INC. AND MAY NOT BE DUPLICATED, COMMUNICATED

TO OTHER PARTIES OR USED FOR ANY PURPOSE WITHOUT THE EXPRESS WRITTEN PERMISSION OF LINCOLN GLOBAL, INC.

PROPRIETARY & CONFIDENTIAL:

3/5/2007

RELEASED A.01 FROM "X"

CHANGE DETAIL:

761-

NOTES:

N.A.

CAUTION:

THIS DEVICE IS SUBJECT TO DAMAGE BY STATIC ELECTRICITY. SEE E2454

BEFORE HANDLING.

N.B. PROGRAM

X14

WITH

ITEM 2

AND LABEL X14 WITH PART NUMBER OF

ITEM 2.

N.C. APPLY

ITEM 3

TO COMPONENT SIDE OF BOARD AS SHOWN.

N.D. DO NOT COAT WITH ENCAPSULATION MATERIAL.

N.E. KEEP MOUNTING HOLES FREE OF ENCAPSULATION MATERIAL. (5 PLACES)

N.F. KEEP TOP SURFACE OF TRIMMERS FREE OF ENCAPSULATION MATERIAL. (2 PLACES)

N.G. KEEP TOP SURFACE OF DIP SWITCH FREE OF ENCAPSULATION MATERIAL.

N.H. APPLY

ITEM 3

AROUND BASE OF J2 & J3 ON BACK SIDE OF BOARD. LIMIT HEIGHT TO

.125 +0/-.0625 INCHES.

N.J. APPLY

ITEM 3

TO CONNECTOR’S PLASTIC MOUNTING PINS.

{

N.A.

{

N.D.

2 3 4 5 6 7

PRECISION TIG

ADVANCED CONTROL

HOT START

ARC FORCE

G4761-1

R116

R15

R144

R67

R16

R12

R151

C53

D13

C50

R121

D12

R156

R60

C37

R159

R157

R24

D14

C63

R176

R105

C28

C19

R146

DZ4

C57

C29

J20

R87

R155

C36

TP4

R89

C35

C55

TP5

R158

C56

R145

C52

R39

R148

R120

R118

C38

LED1

C54

C34

TP2

R14

R102

C46

R123

R88

R99

C10

R104

R177

R119

LED2

R103

C49

R150

C30

C51

R149

C32

D11

R152

R64

R66

R117

R153

R154

D10

R107

TP1

J21

R85

J1,J20,J21

J2, J3 MOUNTED

ON BACK OF BOARD

N.E.

N.F.

N.G.

.20

3.30

ALL COMPONENTS AND MATERIALS USED IN THIS

ASSEMBLY ARE TO BE RoHS COMPLIANT PER E4253

REVISION CONTROL

G4761-1A0

PART NO. IDENTIFICATION

CODE

TEST PER

COAT WITH E1844 AND E3668

SCHEMATIC REFERENCE:

SEE ELECTRONIC FILE FOR ADDITIONAL INFORMATION.

E4298-AC

G4760-1A0

4 LAYER BOARD BLANK PANEL

.20

2.60

5.30

5.50

2.75

3.50

N.B.

MAKE DETAIL

MANUFACTURE PER E1911

BUY BLANK COMPLETE

(6 BOARDS PER PANEL)

N.H.

X X

XX XX

N.J.

N.C.

ITEM

QTY

PART NUMBER

DESCRIPTION

G4761-A

PC BOARD BLANK

S26859-1

PSOC SOFTWARE (X14)

AS REQ E2861

SEALANT

REFERENCES

QTY

PART NUMBER

DESCRIPTION

C1, C2, C4, C5, C7, C10,

C12, C14, C15, C17, C18,

C19, C20, C26, C29, C30,

C31, C32, C33, C34, C38,

C39, C43, C45, C49, C50,

C51, C52, C53, C54, C55,

C56, C57, C62, C63, C65

S25020-3SMT

CAPACITOR,SMD,CERAMIC,0.1MF,50V,10%,X7R,S0805

C3, C8, C58, C64, C66

S25020-2SMT

CAPACITOR,SMD,CERAMIC,0.022MF,50V,10%,X7R,S0805

S25020-5SMT

CAPACITOR,SMD,CERAMIC,2700pF,50V,5%,X7R,S0805

C9, C27, C28, C46

S25020-27SMT

CAPACITOR,SMD,CER,0.1MF,50V,-20%+80%,Z5U,S0805

C11

S25020-9SMT

CAPACITOR,SMD,CERAMIC,47pF,50V,5%,COG,S0805

C35, C36, C37, C48

S25020-24SMT

CAPACITOR,SMD,CERAMIC,1.0MF,25V,10% ,X7R,S1206

C60

S25020-14SMT

CAPACITOR,SMD,CERAMIC,330pF,100V,5%,COG,S0805

S25040-2SMT

DIODE,SMD,1A,400V,DO-214BA/AC

D2, D3, D4, D5, D6, D7,

S25049-4SMT

DIODE,SMD,SCHOTTKY,DUAL,0.200A,30V,SOT-23

D9, D10, D11, D12, D13,

D14

S25040-5SMT

DIODE,SMD,DUAL,0.200A,70V,UFR

DZ1, DZ5

S25046-1SMT

ZENER DIODE,SMD,0.5W,5.1V, 5%,SOD123

DZ3

S25046-4SMT

ZENER DIODE,SMD,0.5W,12V,5%,SOD-123

DZ4

S25046-3SMT

ZENER DIODE,SMD,0.5W,18V, 5%,SOD123

S24020-12

CONNECTOR,MOLEX,MINI,PCB,12-PIN,TIN

J2, J3

S21135-10

CONNECTOR,MOLEX,MINI,BLIND,F,10-PIN

J20

S24020-2

CONNECTOR,MOLEX,MINI,PCB,2-PIN,TIN

J21

S24020-4

CONNECTOR,MOLEX,MINI,PCB,4-PIN,TIN

LED1, LED2

S25080-2SMT

LED,SMD,GREEN,CLEAR,S1206

OCI1

S15000-34SMT

IC,SMD,OPTOCOUPLER,HMA124

Q2, Q3, Q6, Q7, Q8

S25050-1SMT

TRANSISTOR,SMD,NPN,0.5A,40V,SOT-23,MMBT4401LT1

S25051-4SMT

TRANSISTOR,SMD,NMF,SOT-23,0.115A,60V,7002LT1(SS)

R1, R2, R3, R4, R5, R8,

R25

S25000-2211SMT RESISTOR,SMD,METAL FILM,1/10W,2.21K,1%,S0805

R6, R10, R13, R14, R16,

R17, R18, R21, R26, R28,

R29, R32, R33, R48, R52,

R58, R59, R61, R65, R72,

R82, R84, R85, R89, R92,

R101, R102, R103, R104,

R116, R120, R123, R128,

R130, R135, R137, R138,

R139, R140, R141, R143,

R151, R152, R153, R154,

R155, R157,

S25000-1002SMT RESISTOR,SMD,METAL FILM,1/10W,10.0K,1%,S0805

S25058-1SMT

TRIMMER,SMD,ST,1/4W,10K,10%,LINEAR

R9, R148, R175

S25000-6810SMT RESISTOR,SMD,METAL FILM,1/10W,681OHMS,1%,S0805

R11, R35, R36, R106,

R111, R124

S25000-3320SMT RESISTOR,SMD,METAL FILM,1/10W,332OHMS,1%,S0805

R12, R45, R169, R170,

R171

S25000-1000SMT RESISTOR,SMD,METAL FILM,1/10W,100OHMS,1%,S0805

R15

S25000-1372SMT RESISTOR,SMD,METAL FILM,1/10W,13.7K,1%,S0805

R20

S25000-1501SMT RESISTOR,SMD,METAL FILM,1/10W,1.50K,1%,S0805

R22, R142, R144

S25000-2212SMT RESISTOR,SMD,METAL FILM,1/10W,22.1K,1%,S0805

R23, R136, R158

S25000-2002SMT RESISTOR,SMD,METAL FILM,1/10W,20.0K,1%,S0805

R24, R44, R110, R178

S25000-1211SMT RESISTOR,SMD,METAL FILM,1/10W,1.21K,1%,S0805

R27, R46

S25000-3323SMT RESISTOR,SMD,METAL FILM,1/10W,332K,1%,S0805

R30, R31, R70

S25000-4752SMT RESISTOR,SMD,METAL FILM,1/10W,47.5K,1%,S0805

R34, R37, R38, R50, R67,

R75, R76, R127, R131,

R132, R133, R181

S25000-5110SMT RESISTOR,SMD,METAL FILM,1/10W,511OHMS,1%,S0805

R39, R60, R66, R87,

R105, R126, R166, R167,

R177

S25000-4751SMT RESISTOR,SMD,METAL FILM,1/10W,4.75K,1%,S0805

R41, R172, R176, R182,

R183

S25000-47R5SMT RESISTOR,SMD,METAL FILM,1/10W,47.5OHMS,1%,S0805

R42, R43, R47, R64, R68,

R71, R83, R88, R90, R91,

R107, R109, R112, R121,

R145, R146, R147, R174,

R179

S25000-1001SMT RESISTOR,SMD,METAL FILM,1/10W,1.00K,1%,S0805

R49, R51, R77, R134,

R180

S25000-4750SMT RESISTOR,SMD,METAL FILM,1/10W,475OHMS,1%,S0805

R54, R69

S25000-3321SMT RESISTOR,SMD,METAL FILM,1/10W,3.32K,1%,S0805

R55, R125

S25000-1821SMT RESISTOR,SMD,METAL FILM,1/10W,1.82K,1%,S0805

R57, R97

S25000-10R0SMT RESISTOR,SMD,METAL FILM,1/10W,10.0OHMS,1%,S0805

R73, R74, R150

S25000-1003SMT RESISTOR,SMD,METAL FILM,1/10W,100K,1%,S0805

R86

S25000-3162SMT RESISTOR,SMD,METAL FILM,1/10W,31.6K,1%,S0805

R94, R118

S25000-7501SMT RESISTOR,SMD,METAL FILM,1/10W,7.50K,1%,S0805

R95, R117

S25000-2671SMT RESISTOR,SMD,METAL FILM,1/10W,2.67K,1%,S0805

R96

S25084-2SMT

THERMISTOR,SMD,PTC,0.35./1.4OHMS,2.0A

R98, R99

S25001-1210SMT RESISTOR,SMD,121OHMS,1/4W,1206,1%,TR

R108, R122

S25000-9091SMT RESISTOR,SMD,METAL FILM,1/10W,9.09K,1%,S0805

R114, R115

S25000-2000SMT RESISTOR,SMD,METAL FILM,1/10W,200OHMS,1%,S0805

R119, R129

S25000-1822SMT RESISTOR,SMD,METAL FILM,1/10W,18.2K,1%,S0805

R149, R159

T10812-41

TRIMMER,ST,1/2W,10K, 10%,LINEAR

R156

S25000-1652SMT RESISTOR,SMD,METAL FILM,1/10W,16.5K,1%,S0805

S19869-8

SWITCH,DIP,SPST,8-CIRCUITS????SET_SWITCH_POSITIONS????

S15128-11SMT

IC,SMD,COMPARATOR,QUAD,2901D

X2, X6, X11

S15128-28SMT

IC,OP-AMP,SMT,QUAD,HIGH-PERF,33074ADT

S25067-1SMT

IC,BIPOLAR,TIMER,SOIC-14

X8, X13

S15128-4SMT

OP-AMP,SMD,QUAD, GEN-PURPOSE,224D

X9, X12

S15018-6SMT

IC,SMD,CMOS,SWITCH,ANALOG,QUAD, 4066BD(SS)

X10

S25057-2SMT

POT,SMD,DIGITAL,10K,1-CHNL,SOIC-8

X14

S25073-12SMT

IC,SMD,CMOS,PSOC,8-BIT,CY8C27643,TFN49(SS)

X15, X16

S25065-3SMT

IC,SMD,CMOS,INVERTER,SCHMITT,HEX,VHC14(SS)

REFER TO ELECTRONIC COMPONENT DATABASE FOR SPECIFICATIONS ON ITEMS LISTED BELOW

G-31

Summary of Contents for Precision TIG 375

Page 1: ...Safety Depends on You Lincoln arc welding and cutting equipment is designed and built with safety in mind However your overall safety can be increased by proper installation and thoughtful operation o...

Page 2: ...INJURY OR DEATH KEEP CHILDREN AWAY PACEMAKER WEARERS SHOULD CONSULT WITH THEIR DOCTOR BEFORE OPERATING Read and understand the following safety highlights For additional safety information it is stron...

Page 3: ...es from sparks and the rays of the arc when welding or observing open arc welding Headshield and filter lens should conform to ANSI Z87 I standards 4 b Use suitable clothing made from durable flame re...

Page 4: ...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 W...

Page 5: ...onnel travaillant proximit au soudage l aide d crans appropri s et non inflammables 4 Des gouttes de laitier en fusion sont mises de l arc de soudage Se prot ger avec des v tements de protection libre...

Page 6: ...ion C Maintenance Section D Theory of Operation Section E Troubleshooting and Repair Section F How to Use Troubleshooting Guide F 2 PC Board Troubleshooting F 3 Troubleshooting Guide F 4 Test Procedur...

Page 7: ...Ranges A 3 Safety Precautions A 4 Stacking A 4 Lifting and Moving A 4 Tilting A 4 High Frequency Interference Protection A 4 Input Electrical Connections A 5 Ground Connection A 5 Output Cables Connec...

Page 8: ...Power 40 AC DC Stick Balance TIG Unbalance 70 Penetration AC TIG 60 AC DC Stick Balance TIG Unbalance 70 Penetration AC TIG 100 AC DC Stick Balance TIG Unbalance 70 Penetration AC TIG Idle Amps Rated...

Page 9: ...lance Penetration with out Standard Power Factor Correction Capacitors Based on the 1999 U S National Electrical Code RECOMMENDED INPUT WIRE AND FUSE SIZES Input Voltage phase Frequency 208 1 60 230 1...

Page 10: ...N ENVIRONMENTAL RATING Precision TIG 375 power sources carry an IP21S Environmental rating They are rated for use in damp dirty rain sheltered environments HIGH FREQUENCY INTERFERENCE PROTECTION The f...

Page 11: ...n the welder is enclosed in a metal building several earth driven electrical grounds as in 5 above around the periphery of the building are rec ommended Failure to observe these recommended installati...

Page 12: ...ange this con nection designations on the reconnect panel LOW MID and HIGH correspond to the name plated input voltages of a triple voltage welder Dual voltage welders use only LOW and HIGH EXAMPLE On...

Page 13: ...be damaged Never allow the torch to touch the cylinder Keep cylinder away from live electrical cir cuits Maximum inlet pressure 150 psi The Precision TIG machines do not have Hi Freq available at the...

Page 14: ...pumps and large motors have starting currents which are significantly higher than their running current These higher starting currents may cause the circuit breaker to open See next paragraph Both the...

Page 15: ...am The robotic interface functions with the Precision TIG set to either TIG or STICK mode but must be in REMOTE switch position for the Preset Control inter face to function When in the REMOTE positio...

Page 16: ...0 NOTES PRECISION TIG 375 A 10 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 T...

Page 17: ...3 Controls and Settings B 4 Welding Operation B 5 B 8 Internal Set Up Controls B 9 2 Step Trigger Modes B 10 4 Step Trigger Modes B 11 TIG Weld Cycle Chart B 12 Set Up for TIG Amptrol Welding B 13 Ma...

Page 18: ...s AC DC Stick SMAW capability with adjustable Arc Force availability A TIG Pulse Panel Power Factor Capacitors and a Water Solenoid are available as field installed optional kits Also a new Undercarri...

Page 19: ...257 series cannot be used for torch connection PRECISION TIG 375 CODES ABOVE 11000 RECOMMENDED EQUIPMENT INTERFACE TIG water cooled TIG air cooled Machine PT375 Welding Package K2624 1 PT375 K2622 1 2...

Page 20: ...position No panel light When the Polarity Switch is set to AC the TIG mode provides continuous high frequency to stabi lize the arc for AC TIG welding Hi Freq turns on after preflow time with the arc...

Page 21: ...TE posi tion this knob sets the maximum welding level that the Peak output can be set with the remote Amptrol The new MicroStartTM Technology minimum current circuit provides for low end welding down...

Page 22: ...n 5 0 1 2 3 4 5 Description HS TIG Hot Start of output setting 0 Only setting for SS0 above 10 20 30 40 50 60 70 80 90 UP Upslope Time None Only setting for SS1 SS2 above 0 5 sec 1 0 sec 1 5 sec 2 0 s...

Page 23: ...et receptacle is provided for the connection of an Amptrol or other remote control See Figure B 2 When the Current Control Switch See Item 5 is in the REMOTE position the Amptrol or other remote 10K p...

Page 24: ...ined by the SPOT TIME control A red panel light is ON to indicate SPOT mode 14 PULSE FREQUENCY CONTROL This knob is used to set the Pulse Frequency over the peak pulse range of about 0 1 pps to 20 pps...

Page 25: ...00 Prevents stubbing of the electrode by providing extra output current if the arc voltage drops below the level required to sustain the welding arc High 65 and Low 12 factory set levels are selectabl...

Page 26: ...put Current Gas Pre Flow Post Flow Normal Sequence Torch Button Output Current Gas Pre Flow Post Flow START CRATER CURRENT UP SLOPE DOWN SLOPE With DIP Switch 2 OFF With DIP Switch 2 ON As Shipped Act...

Page 27: ...ly end down slope and maintain crater current Hold the trigger for more than 1 second to activate the restart function When the trigger is released up slope will occur Hold the first trigger pull to m...

Page 28: ...ope Time DOWNSLOPE Adjust 0 10 sec w Advan Panel Fixed 0 sec w o POSTFLOW Adjust 2 60 sec or x2 CRATER FILL LEVEL Advanced Panel Select Mach Min or MIN Setting as w o Panel With PULSE ON No Pulsing Du...

Page 29: ...output level FIGURE B 6 A Ad dv va an nc ce ed d P Pa an ne el l C Co on nt tr ro ol ls s SETUP GUIDELINES FOR TIG WELDING WITH AN AMPTROL Both the Hand and Foot Amptrols work in a similar manner The...

Page 30: ...gsten in AC and DC applications Balanced Wave Unbalanced Wave requires derating of the electrode MAKING A TIG WELD WITH AN AMPTROL 1 Install welding equipment per Section A 5 2 Setup controls per Sect...

Page 31: ...TABLE OF CONTENTS ACCESSORIES Accessories Section C Optional Equipment for Codes Above 11000 C 2 Optional Equipment for Codes Below 11000 C 3 Return to Master TOC Return to Master TOC Return to Master...

Page 32: ...oolant inlet and cooler receptacle of Precision TIG Cannot be used with a water cooler K870 Foot Amptrol Single pedal foot activation of arc start switch and output control with 25 plug cable K870 1 S...

Page 33: ...ed in the package K1828 1 Under Cooler Cart Includes a cooler in a drawer with hoses and a lockable storage drawer on a dual bottle undercar riage see below K1869 1 Undercarriage Includes a dual bottl...

Page 34: ...4 NOTES C 4 PRECISION TIG 375 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 TO...

Page 35: ...tions D 2 Routine and Periodic Maintenance D 2 Overload Protection D 2 Service Procedures D 3 Component Location and Access D 3 Spark Gap Adjustment D 3 Under Cooler Service D 3 Major Component Locati...

Page 36: ...the machine with the cooling air The cooling fan will oper ate briefly when the machine power is initially turned on and continuously while the yellow Thermal Shutdown Light is lit see Thermostatic P...

Page 37: ...less high frequency is desired the setting can be reduced to 0 008 inches 0 2 mm Use extreme caution when working with the high frequency circuit The high voltages developed can be lethal Turn the in...

Page 38: ...n 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 Case Front Assembly 2 Arc Starter and Bypass Assembly 3 Case Bac...

Page 39: ...1 X2 AC AC DC DC SHUNT CHOKE HIGH FREQUENCY TRANSFORMER HIGH VOLTAGE TRANSFORMER THERMOSTAT 115 VAC 115 VAC 115 VAC FANS GATE LEADS FEEDBACK GAS SOLENOID 115 VAC 115 VAC LED s THERMOSTATS 20 VAC 20 VA...

Page 40: ...ow of shielding gas It features a stick output terminal front and a universal Tig torch connection box rear for simultaneous but separate electrode outputs INPUT POWER CIRCUIT The desired single phase...

Page 41: ...mer and the cooling fan The advanced control panel also plugs into and interfaces with the control board THEORY OF OPERATION FIGURE E 3 OUTPUT RECTIFICATION CONTROL BOARD AND FEEDBACK POWER SWITCH REC...

Page 42: ...NIMUM OUTPUT CONTROL MAXIMUM OUTPUT CONTROL PROTECTION BOARD REMOTE RECEPTACLE METER STICK TIG SWITCH BALANCE CONTROL POST FLOW LOCAL REMOTE SWITCH Precision Tig 375 FROM CONTROL BOARD X3 STICK OCV BO...

Page 43: ...OWER FACTOR POLARITY SWITCH BYPASS BOARD WORK FRONT ELECTRODE REAR ELECTRODE 78 VAC X1 X2 AC AC DC DC SHUNT CHOKE HIGH FREQUENCY TRANSFORMER HIGH VOLTAGE TRANSFORMER THERMOSTAT 115 VAC 115 VAC 115 VAC...

Page 44: ...rminals The bypass board protects the internal circuitry from interference THEORY OF OPERATION FIGURE E 7 AC WELDING OUTPUT POWER SWITCH RECONNECT PANEL OPTIONAL POWER FACTOR POLARITY SWITCH BYPASS BO...

Page 45: ...t of current into the gate This gate pulse must be more positive than the cathode voltage Since there is a standard PN junction between gate and cathode the voltage between these terminals must be sli...

Page 46: ...L PROTECTION This welder has thermostatic protection from excessive duty cycles overloads loss of cooling and excessive ambient temperatures When the welder is subjected to an overload or inadequate c...

Page 47: ...cal Output Voltage Waveform AC Tig Mode F 40 Typical AC Voltage Waveform 50 AMPS AC Tig Mode F 41 Typical AC Voltage Waveform 2 AMPS AC Tig Mode F 42 Typical Output Voltage Waveform 200 AMPS DC Tig Mo...

Page 48: ...te to the machine symptom Perform these tests checks in the order listed In general these tests can be conducted without removing the case wrap around cover Step 3 RECOMMENDED COURSE OF ACTION The las...

Page 49: ...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 P...

Page 50: ...re you proceed Call 1 888 935 3877 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 1 C...

Page 51: ...1 Check for loose or faulty connec tions on the heavy current carry ing leads Polarity switch output choke output terminals etc 2 Check for faulty connections or a defective thermostat Check leads 213...

Page 52: ...ght 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 fa...

Page 53: ...of the heavy current carrying leads 3 Perform the SCR Bridge Test 4 Perform the T1 Transformer Test 5 Check the output current con trols for proper operation Normal resistance is 10 000 ohms See the W...

Page 54: ...ng 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 output current con trols for proper operation Normal resistanc...

Page 55: ...inal insu lators for cracks or signs of over heating 1 Diode D1 may be shorted Check and replace if necessary 2 Check the polarity switch S2 for proper function and correct con nections 3 Perform the...

Page 56: ...nterference Make 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 prop e...

Page 57: ...e control board 1 Check the high voltage trans former T2 The normal resis tance of the secondary winding is 12 5k ohms ELECTRIC SHOCK CAN KILL When 115 VAC is applied to T2 a very high voltage is deve...

Page 58: ...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 lea...

Page 59: ...may be a welding proce dure problem When AC TIG welding the arc is erratic and there is a loss of clean ing of the work piece 1 The tungsten electrode may be small for the process Use a larg er diame...

Page 60: ...Jumper in connector J 3 If the machine functions normally the Advanced Process panel or harness is defective 1 Welding current may be too high for the electrode size Reduce current control setting or...

Page 61: ...nel or harness is defective 1 Check that either the advanced control board or jumper plug is in J3 on the control board 1 Check R1 potentiometer and associated leads between the control board and plug...

Page 62: ...for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION FUNCTION PROBLEMS The meter does not...

Page 63: ...ch set ting on the board See Installation Manual 1 Check plug J3 on the control board Either the jumper plug or the advanced control board must be plugged into J3 TROUBLESHOOTING REPAIR TROUBLESHOOTIN...

Page 64: ...8 NOTES F 18 PRECISION TIG 375 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 T...

Page 65: ...u 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 C...

Page 66: ...the Mode Switch to the TIG mode and without closing the arc start switch preset the panel maxi mum output control so the panel digital meter reads 200 amps 2 Using a DC avg digital test voltmeter wit...

Page 67: ...X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X DZ16 C47 R274 D58 R93 D21 X11 D65 C106 C35 Q17 D80 Q23 Q14 C31 R96 C128 C152 R318 R333 C76 R331 DZ22 D67 C155 R134 X10 R205...

Page 68: ...2 F 22 PRECISION TIG 375 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 NOT...

Page 69: ...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...

Page 70: ...he input power to the Precision TIG 375 machine 2 Using the 3 8 nut driver remove the right side case cover 3 Locate the Spark Gap Assembly at the lower rear right side of the machine See Figure F 3 4...

Page 71: ...oughout 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 ble...

Page 72: ...o step 6 See Wiring Diagram 6 Unplug P22 from protection board Measure resistance at P22 See Tables 7 If readings below are OK protection board is bad 8 If readings below are wrong remote amptrol or r...

Page 73: ...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 1 888 935 3877...

Page 74: ...rrect transformer secondary voltages per Table F 3 5 Carefully check for 63 5 VAC at leads 267 to lead 268 Lead 268 is located at the background rectifier Note Lead 267 is located at resistor R8 See W...

Page 75: ...X2 X1 TO X3 PRIMARY WINDINGS H1 TO H2 H1 TO H3 H1 TO H4 SECONDARY VOLTAGES 20 VAC 18VAC 85 VAC 75 VAC PRIMARY VOLTAGES 208 VAC 230 VAC 460 VAC NOTE If the input voltages vary the secondary voltages w...

Page 76: ...0 NOTES F 30 PRECISION TIG 375 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 T...

Page 77: ...eason 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 p...

Page 78: ...igger and check for approximately 115 VAC at the solenoid leads 231A and 235 If the correct voltage is present the solenoid should activate and gas should flow 8 If voltage is present at leads 231A an...

Page 79: ...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 1...

Page 80: ...y 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...

Page 81: ...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...

Page 82: ...Figure F 8 3 Perform the following test for all four SCRs See Figure F 8 4 Construct the circuit outline in Figure F 9 One 6V lantern battery can be used Resistor val ues are 10 The voltmeter scale s...

Page 83: ...ter reads 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...

Page 84: ...8 NOTES F 38 PRECISION TIG 375 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 T...

Page 85: ...rom a properly operating machine Note that each ver tical division represents 20 volts and that each horizontal division represents 5 milliseconds in time NOTE Scope probes connected at machine output...

Page 86: ...l voltage and waveform checks with high frequency circuit OFF Perform High Frequency Disable Procedure This is the typical AC output voltage waveform generated from a properly operating machine Note t...

Page 87: ...generated from a properly operating machine Note that each ver tical division represents 20 volts and that each horizontal division represents 5 milliseconds in time NOTE Scope probes connected at ma...

Page 88: ...erform all voltage and waveform checks with high frequency circuit OFF Perform High Frequency Disable Procedure This is the typical AC output voltage waveform generated from a properly operating machi...

Page 89: ...to work NOTE AC balance control set at Balanced position TYPICAL OUTPUT VOLTAGE WAVEFORM MACHINE LOADED TO 200 AMPS DC TIG MODE HIGH VOLTAGE HIGH FREQUENCY can damage test equipment Perform all volta...

Page 90: ...4 F 44 PRECISION TIG 375 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 NOT...

Page 91: ...ughout 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 bles...

Page 92: ...o cut lead 7 Using a 7 16 nut driver disconnect heavy black leads S and F See Figure F 12 8 Using a 3 8 nut driver remove the screw securing the spark gap assembly box See Figure F 12 This will allow...

Page 93: ...TRANSFORMER REMOVAL AND REPLACEMENT continued Figure F 12 3 8 Screw Leads S and F Locations Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC...

Page 94: ...8 NOTES F 48 PRECISION TIG 375 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 T...

Page 95: ...etailed 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 electric...

Page 96: ...cess to the control board and its plugs 4 From left to right label and disconnect plugs J4 J5 J6 J8 J9 J10 J11 J12 See Figure F 14 5 Cut any necessary cable ties 6 Using a phillips head screwdriver re...

Page 97: ...VAL AND REPLACEMENT continued J12 J11 J10 J9 J8 J6 J5 J4 Figure F 14 Control Board Plug Locations Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Return to Mast...

Page 98: ...2 F 52 PRECISION TIG 375 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 NOT...

Page 99: ...his 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...

Page 100: ...Wiring Diagram 6 Remove the three screws mounting the Heat Sink Assembly to the Lift Bale Assembly Note placement of Insulators for reassembly 7 See SCR Replacement Procedures 8 Replace all leads baff...

Page 101: ...or are unable to perform the test repairs safely contact the Lincoln Electric Service Department for electrical trou bleshooting assistance before you proceed Call 1 888 935 3877 DESCRIPTION This proc...

Page 102: ...lint free cloth or paper towel 4 Inspect the mounting surfaces of each new diode Remove all burrs and wipe clean Do not use steel wool or any abrasive cleanser on the diode mount ing surface 5 Apply a...

Page 103: ...er to the technician or machine operator and will invalidate your factory warranty For your safety and to avoid elec trical shock please observe all safety notes and precautions detailed throughout th...

Page 104: ...COMMENDED THAT ALL NEW HARDWARE LEAF SPRING AND HOUSING BE USED FOR REASSEMBLY 2 Remove the old SCR 3 Clean the area on the heat sink around the SCR mounting surface Using a putty knife or similar too...

Page 105: ...spring Orient the leaf spring so that it s ends are curved upward toward the bolt heads See figure F 21 Pressing on the bolt heads should pro duce a rocking motion of the spring in its housing If the...

Page 106: ...turn 4 Tighten first cap screw 1 2 turn 5 Tighten second cap screw 1 2 turn 6 Tighten first cap screw 1 4 turn 7 Assembly now has proper clamping force 8 Perform the Active SCR Test CLAMPING PROCEDUR...

Page 107: ...on the bolt heads should produce a rocking action of the spring in it s housing 5 Insert clamp assembly thru heat sinks Install nuts Tighten clamp nuts equally on bolts until finger tight Be sure tha...

Page 108: ...2 F 62 PRECISION TIG 375 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 NOT...

Page 109: ...s 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 as...

Page 110: ...slot head screw drivers carefully pry the polarity switch handle from the shaft 8 Carefully peel back the lower nameplate on the case front located around the polarity switch to gain access to the pol...

Page 111: ...RCUIT VOLTAGES MAXIMUM AC OPEN CIRCUIT VOLTAGE MAXIMUM DC OPEN CIRCUIT VOLTAGE 75 VAC 68 VDC MAXIMUM ACCEPTABLE OUTPUT VOLTAGE AT MINIMUM OUTPUT SETTINGS DC TIG Mode 2 5 Amps 20 Volts MAXIMUM ACCEPTAB...

Page 112: ...6 F 66 PRECISION TIG 375 NOTES 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 T...

Page 113: ...2 G 14 Control P C Board Schematic Codes above 11000 G4762 Page 3 G 15 Control P C Board Schematic Codes above 11000 G4762 Page 4 G 16 Control P C Board Schematic Codes above 11000 G4762 Page 5 G 17 C...

Page 114: ...220A G4 218 SCR4 D1 X1 NEG SCR3 POS SCR1 SCR2 252 B 224 G4047 3 8 2002A PRECISION TIG 375 WIRING DIAGRAM L9 L10 L6 L5 L4 L13 L11 411 W 403 404 405 406 407 408 409 410 401 402 TIG OPTION PCB J1 1 3 4 5...

Page 115: ...20A G4 218 SCR4 D1 X1 NEG SCR3 POS SCR1 SCR2 252 B 224 G4047 1 3 8 2002A PRECISION TIG 375 WIRING DIAGRAM L9 L10 L6 L5 L4 L13 L11 411 W 403 404 405 406 407 408 409 410 401 402 TIG OPTION PCB J1 1 3 4...

Page 116: ...S INTO LOWER SWITCHED RECEPTACLE PRECISION TIG 375 WIRING DIAGRAM L9 L10 L6 L5 L4 L13 L11 411 W 403 404 405 406 407 408 409 410 401 402 TIG OPTION PCB J1 06 17 20 02 1 3 4 5 6 8 9 10 7 2 1 3 4 5 6 8 9...

Page 117: ...VIEW OF CONNECTOR ON PC BOARD ELECTRICAL SYMBOLS PER E1537 SYMBOLES LECTRIQUES SELON E1537 S MBOLOS EL CTRICOS CONFORME A E1537 COMPONENT VALUE UNITS RESISTORS OHMS WATTS CAPACITORS MFD VOLTS 8 0F CON...

Page 118: ...BINA DE RELEVADOR DE 12V DE AC DIODE ROUE LIBRE DIODO DE RUEDA LIBRE L1 INDUCTEUR DE SORTIE STARTER INDUCTOR DE SALIDA ESTABILADOR INDUCTEUR DE HAUTE FR QUENCE INDUCTORES DE ALTA FRECUENCIA STARTERS T...

Page 119: ...R X14 231B 231E 236 TOROID TOROID HI FREQ 115VAC GAS 115VAC FAN 115VAC 235 260 265 266 252 253 MICRO SWITCH ON POLARITY SWITCH VOLT FEEDBACK ELECTRODE VOLT FEEDBACK WORK 265 266 252 253 MICRO SWITCH O...

Page 120: ...BALANCE REMOTE RED GREEN GREEN GAS GREEN THERMAL YELLOW B W B W B W B W 331 332 333 B W 334 335 331 331 332 332 333 333 334 334 335 335 B W B W B W B W B W 6J10 1J10 7J10 2J10 8J10 3J10 9J10 4J10 10J1...

Page 121: ...AGE 1 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Ret...

Page 122: ...GE 2 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Retu...

Page 123: ...GE 3 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC Retu...

Page 124: ...C159 37 S16668 5 CAPACITOR CEM O 022 50V 20 C14 C127 2 S13490 25 CAPACITOR TAEL 4 7 35V 10 C15 C141 C164 3 S13490 181 CAPACITOR ALEL 22 63V 20 C22 C51 2 T11577 54 CAPACITOR CD 750PF 1000V 10 C23 C39 C...

Page 125: ...62 PAGE 1 G 13 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sectio...

Page 126: ...62 PAGE 2 G 14 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sectio...

Page 127: ...62 PAGE 3 G 15 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sectio...

Page 128: ...62 PAGE 4 G 16 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sectio...

Page 129: ...62 PAGE 5 G 17 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sectio...

Page 130: ...38 C62 C72 C73 C74 C75 C79 C80 C88 C91 C104 C107 C112 C128 C134 C142 C144 C145 C146 C147 C150 C151 C152 C153 C154 C156 C159 C170 31 S16668 5 CAPACITOR CEMO 022 50V 20 C22 C51 2 T11577 54 CAPACITOR CD...

Page 131: ...CHANGE J23 2 MFD CAPACITORS RESISTORS Ohms UNLESS OTHERWISE SPECIFIED 1A 400V ELECTRICAL SYMBOLS PER E1537 DIODES UNLESS OTHERWISE SPECIFIED GENERAL INFORMATION 1 4W 022 50V LABELS UNLESS OTHERWISE SP...

Page 132: ...d may result in danger to the Machine Operator or Technician Improper PC board repairs could result in damage to the machine ELECTRICAL DIAGRAMS G 20 PRECISION TIG 375 PC BOARD ASSEMBLY PROTECTION M16...

Page 133: ...ED 1 4W OF A COMPLETE ELECTRICAL SYMBOLS PER E1537 EARTH GROUND CONNECTION Graphic Graphic FRAME CONNECTION ARC STABILIZER CAPACITOR RESISTOR N A SHOW THE EXACT COMPONENTS COMMON CONNECTION AND SCREW...

Page 134: ...e 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 ELECTRICAL DIAGRAMS G 22 PRECISION TIG 375 PC BOA...

Page 135: ...ION OWNED BY THE LINCOLN ELECTRIC CO AND IS NOT TO BE REPRODUCED DISCLOSED OR USED WITHOUT THE EXPRESS PERMISSION OF UNLESS OTHERWISE SPECIFIED THE LINCOLN ELECTRIC CO CIRCUIT BOARD S WITH PUBLISHED S...

Page 136: ...y result in danger to the Machine Operator or Technician Improper PC board repairs could result in damage to the machine ELECTRICAL DIAGRAMS PRECISION TIG 375 PC BOARD ASSEMBLY BYPASS AND CE L10882 1...

Page 137: ...4039 PAGE 1 G 25 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sect...

Page 138: ...4039 PAGE 2 G 26 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sect...

Page 139: ...3 D4 D5 D6 D7 D9 5 S25040 5SMT DIODE SMD DUAL 0 200A 70V UFR DZ1 1 S25046 1SMT ZENER DIODE SMD 0 5W 5 1V 5 SOD123 DZ2 DZ3 2 S25046 4SMT ZENER DIODE SMD 0 5W 12V 5 SOD 123 N D J1 1 S24020 12 CONNECTOR...

Page 140: ...4760 PAGE 1 G 28 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sect...

Page 141: ...4760 PAGE 2 G 29 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sect...

Page 142: ...4760 PAGE 3 G 30 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Return to Section TOC Return to Section TOC Return to Section TOC Return to Sect...

Page 143: ...1 S25020 5SMT CAPACITOR SMD CERAMIC 2700pF 50V 5 X7R S0805 C9 C27 C28 C46 4 S25020 27SMT CAPACITOR SMD CER 0 1MF 50V 20 80 Z5U S0805 C11 1 S25020 9SMT CAPACITOR SMD CERAMIC 47pF 50V 5 COG S0805 C35 C...

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Summary of Contents for Precision TIG 375

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Lincoln Electric Precision TIG 375, Service Manual, Page: 143 / 143

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Summary of Contents for Precision TIG 375

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