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OWNER`S MANUAL TIG160S/180S/200S TIG180A/250A/400A INSTRUCTION MANUAL PRODUCTS INTRODUCE Tig160S/180S/200S are single process argon-arc welding. Tig180A/250A/400A are two processes of sticking and argon-arc welding(choose it by function switch). As sticking , outer characteristics of welding machine are continue current and arc drive controlling .It is constant current characteristics when arc voltage is normal ,it makes that welding current will not be changed with arc length .Current will become higher and higher with arc voltage down-slope ,when arc voltage is too low ,it makes that arc length will return into normal range (it is arc driving). When arc voltage is too low to support arc, voltage will down slope immediately in order to protect from splashing which is caused by short circuit . Arc welding characteristic is continue current ,welding current will not change arc length ,so current is very stabilizing .When electrode circuit is short ,current will declined to 0 automatically in order to protect tungsten ad work piece . TIG160S/180S/200S/180A/250A/400A MAIN TECHNICAL DATA Model TIG160S TIG180S TIG200S TIG180A TIG250A TIG400A Item Power voltage(v) AC200v±15% 50/60 AC200v±15% 50/60 AC200v±15% 50/60 AC200v±15% 50/60 Three phase AC380v±15%, 50/60 Three phase AC380v±15%, 50/60 Input current(A) 160 180 200 180 250 400 No-load voltage(V) 42 55 42 55 75 82 Output current adjustment range (A) 10~160 10~180 10~200 10~180 10~250 25~400 Rate work voltage(V) 16.4 17 18 17 20 26 Driving adjustment range (A) -- -- -- -- 0~100 0~100 Duty cycle 60% 60% 60% 60% 60% 60% loss 35 40 35 40 60 100 Pilot arc model HF HF HF HF HF HF Efficiency 85% 85% 85% 85% 85% 85% Power factor 0.93 0.93 0.93 0.93 0.93 0.93 Insulation class B B B B B B Protection class IP21 IP21 IP21 IP21 IP21 IP21 Weight(kg) 8 9 9 8 13 22 Overall Dimensions 371x155x287 371x152x287 371x155x287 371x152x290 423x205x357 473x330x360 No-load (W) INSTALLATION When use longer cable ,please choose cable of bigger section in order to protect voltage from stepping down .If torch cable is too long ,it maybe effect to function of arc-striking and other function of system .So we suggest that user must use coordinated length which is recommended by manufacturer . Input Cable Connection 1. Every welding machine has disposed a once power cable, power cable must be connected to corresponding voltage in compliance with input voltage .If single phase 220v DC power cable is connected to 380v AC power cable by carelessness ,it makes power is in over-voltage protection position . Please turn power supply off first ,then connect to power cable of 220v and open machine again . Input voltage of TIG160/180/200 is single phase 220v . Input voltage of TIG250/400 is three phase 380v . 2. Make sure that power cable is connected to power switch or connector firmly and prevent from oxidizing . Check if the power voltage is inside waved range . Output Cable Connection 1. Argon-arc welding:TIG160S/180S/200S 1) Connect to gas source : Make sure that argon tube is connected to copper tip tightly .Supply gas circuit must includes gas cylinder ,argon flow meter and gas tubes .Tubes must be tied firmly by laryngeal hoop or something else in order that gas is leaked and air come into . 2) Make sure that mantle has been grounded by cable whose section is min 6 square millimeter in order to prevent static electricity and leaking .The cable is connected to the ground plug pin behind machine . 3) Connect welding torch according to diagram .Electrify integration connector of welding torch and air plug are installed to coordinated connectors then tighten firmly . 4) Mobile plug of return circuit cable is inserted in mobile socket of positive electrode then tightened it clockwise rotation firmly , another terminal of grounding pincer clamps work piece . 2.Sticking And (TIG180A/250) Argon-arc Welding Two Processes Machine When use argon-arc welding ,please connect as aforementioned .When use sticking ,pay attention as following: 1) Every machine has a pair of mobile plugs ,cable of welding handle is connected to black mobile plug ,another terminal of grounding pincer is connected to red mobile plug ,then they must be tightened . Make sure secondary cables (handle cable and grounding cable) are connected to mobile plug reliably . 2) Insert the mobile plug in mobile socket , then tighten it .Or the plug and socket will be burned up if current is too high or working time is too long . Pay attention the electrode of connection cable ,There are two methods of connection that are positive connection and negative connection .Positive connection is that work piece is connected to positive electricity and torch handle is connected to negative electrode , negative connection is that work piece is connected to negative electricity and torch handle is connected to positive electrode . OPERATION TIG160S/200S Control Panel Description 1. Argon-arc Welding 1) Make sure the power switch is on “on” position ,and the indicator will be lit . 2) Open the valve of argon cylinder ,adjust the volume of flow meter and make it is adequate to welding . 3) Inter axial-flow fan begins to work ,press the control knob of torch ,the electromagnetic valve will start ,user can hear sound of HF arc-striking ,at the same time torch tip will flow out argon . 4) Knob of arc-striking push is use to adjust welding function ,specially in low current arrange ,that is cooperated with knob of welding current adjustment ,they may adjust current of arc-striking and be out of control of knob of welding current adjustment .So machine can grain powerful energy and push current can achieve effect that may imitate DC welder revolving . 5) It is 2-4 mm from welding tungsten electrode to work piece ,press control knob of torch ,burn and strike arc , sound of HF arc-striking will be diminished .The welding machine can be operated now . 2. Sticking Description 1) 2) 3) 4) Open the power switch of front control panel ,fan starts to working . Make sure the function switch is on “down” position . Set the welding current is adequate to thickness of work piece . Adjust welding characteristic by drive knob (TIG250/400) . NOTE: Do not touch any cable and connector when the machine is working ,it will damage to health of people and machine . Stainless steel sheet tungsten sticking data (for reference only) Thickness (mm) Connection model Tungsten electrode diameter(mm) Wire diameter (mm) Current type Welding current (A) Argon flow (L/min) Welding speed (cm/min) 1.0 1.2 1.5 Connect directly 2 2 2 1.6 1.6 1.6 DC positive connect 7~28 15 5~19 3~4 3~4 3~4 12~47 25 8~32 Titanium and titaniferous-alloy tungsten sticking data (for reference only) Thickness Slope Number Tungsten Wire Welding Air flow Tip inter- (mm) model of electrode diameter current (L/min) diameter welding diameter layer 0.5 I shape 1 1.5 1.0 30~50 8~10 6~8 14~16 10 1.0 1 1.0 1.0~2.0 40~60 8~10 6~8 14~16 10 1.5 1 2.0 1.0~2.0 60~80 10~12 8~10 14~16 10~12 2.0 1 2.0~3.0 1.0~2.0 80~110 12~14 10~12 16~20 12~14 2.5 1 2.0~3.0 2.0 110~120 12~14 10~12 16~20 12~14 3.0 Y shape 1~2 3.0 2.0~3.0 120~140 12~14 10~12 16~20 12~14 4.0 2 3.0~4.0 2.0~3.0 130~150 1212~ 12~14 20~25 18~20 5.0 2~3 4.0 3.0 130~150 14~14 12~14 20~25 18~20 6.0 2~3 4.0 3.0~4.0 140~180 12~14 12~14 25~28 18~20 7.0 2~3 4.0 3.0~4.0 140~180 12~14 12~14 25~28 20~22 8.0 2~4 4.0 3.0~4.0 140~180 12~14 12~14 25~28 20~22 10 Double 4~6 4.0 3.0~4.0 160~200 14~16 12~14 25~28 20~22 20 Y shape 12 4.0 4.0 200~240 12~14 10~12 20 18 22 12 4.0 4.0~5.0 230~250 15~18 18~20 18~20 20 25 15~16 4.0 3.0~4.0 200~220 16~18 20~26 26~30 22 30 17~18 4.0 3.0~4.0 200~220 16~18 20~26 26~30 22 Aluminium and aluminium alloy tungsten electrode sticking data (for reference only ) Thickness Slope Number of Tungsten Wire Preheat Welding (mm) model welding electrode diameter temperature current layer(positive diameter Argon flow (L/min) Tip interdiameter (mm) /reversal) (mm) 50~80 50~80 7~9 8~12 8 8~12 (℃) 1.5 I 1/0 2 1.6~2.0 2 shape 1/0 2~3 2~2.5 --- 3 4 5 8 10 12 16 20 Y model 1/0 3 2~3 -- 15~180 8~12 8 1~2/1 4 3 -- 180~200 10~15 8~12 1~2/1 4 3~4 -- 180~240 10~15 8~12 2/1 5 4~5 100 260~320 16~20 10~12 3~4/1~2 5 4~5 100~150 280~340 16~20 14~16 3~4/1~2 5~6 4~5 150~200 300~360 18~22 14~16 4~5/1~2 6 5~6 200~220 340~380 20~24 16~20 4~5/1~2 6 5~6 200~260 360~400 25~30 20~22 16~20 Double 2~3/2~3 6 5~6 200~260 300~380 25~30 16~20 22~25 Y shape 2~3/2~3 6~7 5~6 200~260 360~400 30~35 20~22 Stainless steel impulse tungsten electrode argon-arc welding data Thickness (mm) 0.3 0.5 0.8 Current (A) Sustained time (s) Impuls e cardinal volume impulse Cardinal volume Impulse frequency (Hz) 20~22 55~60 85 5~8 10 10 0.06~0. 08 0.08 0.06 0.06 0.08 8 7 5 Welding speed (cm/min) 50~60 55~60 80~100 TIG180P/TIG200P/TIG315P(IGBT) PRODUCTS INSTUCTION TIG180P/200P/315P are impulse inverter DC argon-arc welding and sticking two processes machines ,They are new type welding machines ,specially TIG315P is developed by advantaged electron switch device (IGBT) of 90`s. It has functions as follow: 1) Supply gas beforehand . 2) Current is up slope . 3) Current is down slope . 4) Shut gas off relayed . 5) Control arc- striking automatic . 6) Collect arc . 7) Impulse current frequency . 8) Impulse current empty rate . 9) Impulse cardinal volume etc.. TIG180P/TIG200P/TIG315P(IGBT) MAIN TECHNICAL DATA Model TIG315(IGBT) TIG200P TIG180P Input voltage(v) Three phase 380v±10%,50/60Hz 220v±15%,50/60Hz 380v±10%,50/60Hz Input current(A) 12.7 20 20 Rate output voltage(v) 22.6 18 17 Rate output current(v) 5-315 10-200 10-180 No-load voltage(v) 54 42 55 Polite arc model HF HF HF Duty cycle 60% 60% 60% Cardinal volume current(A) 5-315 20-180 18-162 Current up-slope time 0-10(S) -- -- Current down-slope time 0-10(S) -- -- LF: 0.5-5 MF: 25-250 LF: 0.5-5 MF: 50-200 MF:0-250 10-90(%) -- -- Primary current(A) 5-315 -- -- Collect arc current(A) 5-315 -- -- Post flow(S) 1-10 -- -- Weight(kg) 35 9 8 540X285X445 423X205X357 347X152X290 Item Impulse frequency(Hz) Impulse wide Dimension(wxdxh)mm INSTALLATION 1. Connect to gas source : Make sure that argon tube is connected to copper tip tightly .Supply gas circuit must includes gas cylinder ,argon flow meter and gas tubes .Tubes must be tied firmly by laryngeal hoop or something else in order that gas is leaked and air come into . 2. Mantle must be grounded reliably by cable whose section is min 6 square millimeter .Make sure the grounding terminal of power socket is single grounded reliably . 3. Connect torch or welding pincer according diagram ,If user uses sticking ,make sure cable is connected to torch and mobile plug firmly .The way is that mobile plug should be inserted in mobile socket of negative electrode then tighten them clockwise rotation .If user uses impulse argon-arc welding ,make sure electrify integration connector is installed to interface of board and tightened them clockwise rotation by spanner then insert air plug of torch in coordinated interface of board and tighten its screw . 4. Insert mobile plug of cable in mobile socket of positive electrode and tighten them clockwise rotation , ground cable pincer of another extremity holds work piece . 5. Insert power plug in socket of coordinated model .Make sure supply power voltage is AC 220v and its error is inside allowable arrange . TIG180P/TIG200P/TIG315P(IGBT) OPERATION INTRODUCE 1. Argon-arc Welding Introduce TIG180P/TIG200P 1) Open power switch of front panel ,at this time indicator of power switch will turn on ,inter axial-flow fan begins to work . 2) Open argon cylinder valve ,adjust flow and make it is adequate to welding. 3) Make sure the welding change-over switch of front panel is on “top” position(TIG) . 4) If impulse change-over switch is on “down” position that indicate no impulse ,if switch is on “medium” position that indexes MF impulse(frequency is seen data diagram) ,if switch is on “top ” position that indicate LF impulse(frequency is seen data diagram) .User can choose freely according to welding requirement .Choose suitable impulse frequency by adjust impulse knob . 5) Current can be down-slope by current down-slope time knob ,if current need not be down-slope ,current down-slope time knob is revolved counter clockwise to end . 6) Make sure crest and volley current (when impulse switch is on “down” position ,there is no volley current.) are adequate to thickness of work piece . 7) Press control knob of torch , electromagnetic valve is starting and sound of HF arc-striking can be heard .At the same time argon is flowing out from torch burner . 8) It is 2-4 mm from tungsten electrode to work piece .Once torch knob is pressed and arc is burned ,sound of arc-striking is extinguished .Welding machine can be operated now . TIG315P(IGBT) 1. Open power switch ,fan is beginning to work . 2. Open the valve of argon cylinder and adjust the flow . 3. Make sure the welding change-over switch of front panel is on “up” position that is argon-arc welding(TIG) . 4. If impulse choose switch is on “down” position that indexes no impulse ,if switch is on “medium” position that indexes HF impulse ,if switch is on “up ” position that indicate LF impulse .User can choose freely according to welding requirement .Choose suitable impulse frequency by impulse adjustment knob . 5. Choose suitable welding pattern (2T/4T) :2T is normal impulse argon-arc welding ,4T is all functions welding .Operation description as following : 1) Adjust arc-striking current ,current up-slope time ,welding current ,cardinal volume current ,current down-slope time ,collect arc current and supply gas time . 2) It is 2-4 mm from tungsten electrode to work piece .Press switch of torch and burn arc ,then loose grip .At this time current slopes up to crest current ,user can operate normally .When work piece is finished welding ,press down hand switch and current slope down to collect arc current ,loose grip after the concave of welding spot is be smoothed . 6. Make sure crest and valley current are adequate to thickness of work piece( when impulse switch is on “down” position ,that is no valley current .) 7. Press control knob of torch , electromagnetic valve is started and sound of HF arc-striking can be heard .At the same time argon is flowing out from torch burner . 8. It is 2-4 mm from tungsten electrode to work piece .Once torch knob is pressed and arc is burned ,sound of arc-striking is diminished .Welding machine can be operate . STICKING DESCRIPTION 1. Open power switch of front panel ,fan is beginning to work . 2. Make sure function switch of front panel is on “down” position that is sticking . Impulse change-over switch and knob of current down-slope time will not work . 3. Make sure welding current is adequate to thickness of work piece . QUESTION IS BE RUN INTO IN WELDING Fittings ,gas ,environment factor ,supply power maybe have something to do with welding .User must try to improve welding environment . A. Black welding spot Welding spot is not prevented from oxidizing .User may check as following : 1. Make sure the valve of argon cylinder is opened and its pressure is enough .argon cylinder must be filled up to enough pressure again if pressure of cylinder is be low 0.5Mpa . 2. Check if the flow meter is opened and has enough flow .User can choose different flow according to welding current in order to save gas .But too small flow maybe cause black welding spot because preventive gas is too short to cover welding spot .We suggest that flow of argon must be kept min 5L/min. 3. Check if torch is in block . 4. If gas circuit is not air-tight or gas is not pure can lower welding quality . 5. If air is flowing powerfully in welding environment ,that can lower welding quality . 6. Empty rate is set too low . B. Arc-striking is difficult and easy to pause . 1. Make sure quality of tungsten electrode is high . 2. Grind end of the tungsten electrode to taper .If tungsten electrode is not grinded ,that will be difficult to strike arc and cause unstable arc . C. Current is not stabilizing when machine is been operating. It has something with factors as following : 1. Electric wire net voltage has been changed . 2. There is harmful interference from electric wire net or other equipment . NOTES OR PREVENTIVE MEASURES 1. Environment 1) The machine can perform in environments where conditions are dry with a dampness lever of max 90% . 2) Ambient temperature is between –10 and 40 degrees centigrade . 3) Do not place the machine in positions where the air flow through the cooling air slots is obstructed or limited . 4) Avoid to weld in sun shine or drippings . 5) Do not use the machine in environment where condition is polluted with conductive dust on the air or corrosiveness gas on the air . 2. Safety norms Riland welding machine has installed protection circuit of over voltage and current and heat .When voltage and output current and temperature of machine is exceed the rate standard ,welding machine will stop working automatically .Because that will be damage to welding machine ,user must pay attention as following : 1) The working area is adequately ventilated ! Riland welding is powerful machine ,when it is being operated ,it generated by high currents ,natural wind will not satisfy machine cooled demands .So there are two axial-flow fans in inter-machine to cool down machine . Make sure two ends of fan and front shutter are not in block or covered ,it is 0.3 meter from welding machine to objects of environment .User should make sure the working area is adequately ventilated ,it is very important to machine . 2) Do not over-load ! Keep welding current is not exceed max duty cycle current . Over-load current will damage and burn up machine . 3) No over-voltage! Power voltage can be found in diagram of main technical data .Automatic compensation circuit of voltage will assure that welding current keep in allowable arrangement .If power voltage is exceed allowable arrangement limited ,it is damage to components of machine . 4) There is a grounding screw behind welding machine ,there is grounding marker on it .Mantle must be grounded reliably with cable which section is over 6 square millimeter in order to prevent from static electricity and leaking . 5) If welding time is exceeded duty cycle limited ,welding machine will stop working for protection .Because machine is overheated ,temperature control switch is on “on” position . MAINTENANCE 1. Remove dust by dry and clean compressed air regularly ,if welding machine is operating in environment where is polluted with smokes and pollution air ,the machine need remove dust everyday . 2. Pressure of compressed air must be inside the reasonable arrangement in order to prevent damaging to small components of inter-machine . 3. Check inter circuit of welding machine regularly and make sure the cable circuit is connected correctly and connectors are connected tightly (specially insert connector and components ). If scale and loose are found ,please give a good polish to them ,then connect them again tightly . 4. Avoid water and steam enter into inter-machine ,if them enter into machine ,please dry inter-machine then check insulation of machine (include between connectors and mantle , between connectors and connectors ) 5. If welding machine will not be operated long time ,it must be put into packing box and store in dry environment . THECK FAULT 1. Maintenance or repairs performed by technical assistance centers not authorized by Riland will immediately render null and void the manufacturer warranty . 2. If user want to operate machine as following ,the operator must be a personnel in a specific field of electrify and safety . TIG160S/180S/200S/180A/180P/200P Faults Resolvable Methods 1.Power indicator is 1. Power switch is out of work . not lit ,fan does not 2. Check if electrify wire net (which is connected to input cable )is in work and no welding work. . output 3. Check if input cable is out of circuit . 2.Power indicator is lit ,fan does not work or revolve several circles ,no welding output 1. Maybe connect wrong to 330v power cause machine is in protection circuit ,connect to 220v power and operate machine again . 2. 220v power is not stable,(input cable is too slender)or input cable is connected to electrify wire net cause machine is in protection circuit .Add the section of cable and tighten input connector firmly .Close machine 2-3 minutes then open it again. 3. Cable is loosed from switch to power panel ,tighten them again . 4. Open and close power switch constantly in short time cause machine is in protection circuit Close machine 2-3 minutes then open it again . 5. Main circuit 24v relay of power panel is not close or has damaged .Check 24v power source and relay .If relay has damaged replace it with same model. 3. Fan is working , indicator is not lit and sound of HF arc-striking can not be heard ,wiping welding can not strike arc. 1.Positive and negative electrodes of VH-07 insert component voltage should be about DC308v from power panel to MOS board . (1) If circuit is broken and silicon bridge is poor contact . (2) If some of four high electrolytic(about 470UF/450V) of power panel capacitor is leaking . 2.There is a green indicator in auxiliary power of MOS board ,if it is not on ,auxiliary power is out of work .Check fault spot and connect with seller . 3.Check if connectors is poor contact . 4.Check control circuit and find out reasons or connect with seller. 5.Check if control cable of torch is broken. 4.Abnormal indicator is not on ,sound of HF arc-striking can be heard ,but there is no welding output . 1. Check if torch cable is broken . 2. Check if grounding cable is broken or not connected to welding piece . 3. Output terminal of positive electrode or torch electrify is loosed from inter-machine . 5.Abnormal indicator is not lit ,sound of HF arc-striking can not be heard ,wiping welding can strike arc . 1. Primary cable of arc-striking transformer is not connected to power panel firmly ,tighten it again. 2. Arc-striking tip is oxidized or too far ,give a good polish to it or change it is about 1 mm between arc-striking tip . 3. Switch(sticking/argon-arc welding) is damaged ,replace it . 4. Some of HF arc-striking circuit components is damage ,find out and replace it . 6.Abnormal indicator is lit but there is no welding output . 1. Maybe it is overheated protection ,please close machine first ,then open the machine again after abnormal indicator is out . 2. Maybe it is overheated protection ,wait for 2-3 minutes (argon-arc welding does not has overheated protection function .) 3. Maybe inverter circuit is in fault ,please pull up the supply power plug of main transformer which is on MOS board (VH-07 insert which is near the fan)then open the machine again. (1) If abnormal indicator is still lit ,close machine and pull up supply power plug of HF arc-striking power source (which is near the VN-07 insert of fan ),then open machine : a. If abnormal indicator is still lit ,some of fieldistor of MOS board is damaged ,find out and replace it with same model . b. If abnormal indicator is not lit , rise transformer of HF arc-striking circuit is damaged ,replace it . (2) If abnormal indicator is not lit , a. Maybe transformer of middle board is damage ,measure inductance volume and Q volume of main transformer by inductance bridge(L=0.9-1.6mH Q>35) .If volume is too low ,please replace it . b. Maybe secondary rectifier tube of transformer is damaged ,find out faults and replace rectifier tube with same model . 4.Maybe feedback circuit is broken . 7.Output current is not stabilizing or out of potentiometer control and sometime is high ,sometime is low . 1. 1K potentiometer is damage ,replace it . 2. All kinds of connectors are poor contact ,specially inserts etc. ,please check it . 8.Sticking spatter is much and caustic electrode of is 1.Electrode is connected wrong ,exchange grounding cable and handle cable . difficult . TIG250/400 Faults Resolvable Methods 1.Fan does not work and numerical screen is not indicating , there is no welding output . 1. Make sure air switch is closed . 2. Make sure electrify wire net of output cable can supply power . 3. Some of heat-variable resistors (four) of power panel is damaged ,when it happen ,general DC24v relay is open or connectors is poor contact . 4. Power panel (bottom board )is damaged ,DC537v voltage can be output . (1) Silicon bridge is broken or connector of silicon bridge is poor contact . (2) Power panel has been burned up . (3) Check contact and insert cable from air switch to power panel are poor contact ,check contact and insert cable from power panel to MOS board are connected reliably . 5. Auxiliary power of control panel is in fault . 2.Fan works ,abnormal indicator is not lit ,there is no sound of HF arc-striking ,wiping arc welding can not strike arc. 1. Check if all kinds of cables of inter-machine are poor contact . 2. There is some fault in control panel ,find out reason and connect with seller . 3. Control cable of torch is broken . 3.Abnormal indicator is not lit ,sound of HF arc-striking can be heard ,there is no welding output . 1. Torch cable is broken . 2. Grounding cable is broken or not connected to welding piece. 3. Positive electrode terminal or torch electrify terminal is loosed from inter-machine . 4.Abnormal indicator is not lit ,there is no sound of HF arc-striking ,wipe welding can strike arc. 1. Primary cable of arc-striking transformer is not connected to arc-striking panel reliably ,tighten it again . 2. Arc-striking tip is oxidized or too far ,give a good polish to it or change it is about 1 mm between arc-striking tip . 3. Switch(sticking/argon-arc welding) is damaged ,replace it . 4. Some of HF arc-striking circuit components is damage ,find out and replace it . 5.Abnormal indicator is lit and there is no welding output . 1. Maybe it is overheated protection ,please close machine first ,then open the machine again after abnormal indicator is not lit . 2. Maybe it is overheated protection ,wait for 2-3 minutes (argon-arc welding does not has overheated protection function .) 3. Maybe inverter circuit is in fault ,please pull up the supply power plug (VH-07 insert which is near the fan) near the transformer which is on MOS board then open the machine again. (1) If abnormal indicator is still lit ,close machine and pull up supply power plug of HF arc-striking power source (which is near the VH-07 insert of fan ),then open machine : a. If abnormal indicator is still lit ,some of fieldistor of MOS board is damaged ,find out and replace it with same model . b. If abnormal indicator is not lit , up-slope transformer of HF arc-striking circuit is damaged ,replace it . (2) If abnormal indicator is not lit , a. Maybe transformer of middle board is damage ,measure inductance volume and Q volume of main transformer by inductance bridge. Primary inductance and Q volume of TIG250 main transformer L=0.9-1.6mH Q>35. Primary inductance and Q volume of TIG400 main transformer L=1.2-2.0mH Q>35 . b. Maybe secondary rectifier tube of transformer is damaged ,find out and replace rectifier tube with same model . 4. Maybe feedback circuit is broken . 6.Welding current is 1. Secondary cable is too long and slander ,short length and increase not enough section of secondary cable . high ,current 2. If there is remote control device ,it is in remote control station . adjustment is out of 3. Maybe current adjustment potentiometer is damaged . control.