Tig Welder Wont Fire up (not sure which section sorry if wrong)

[glanzav.tee]

hi all i've joined this forum today hoping i'd get some answers and get my welding techniques brazing away

i have a slight problem i have a chinese tig 3 in 1 yeh i know i should have got a better one but i dont use it everyday its once ot twice in a year, but no it wont arc at all and the tig torch dont come on at all, i've opend it up and check where the clamp and arc stick has voltage approximately about 230 volts but if i try to weld no spark at all plain dead, i've removed the boards and have to say the top control board had quiet a lot of dry solder and some places non at all, i've gone through all this and checked all transistors resistors, diodes, transformer coils, relays which all click ok, so my question to you is have you any idea which controls the sparking or should i say the arcing. thankyou for everyone that answers but i should have bought a better one i know but budget as i dont use it much

 

[eddie49]

An inverter TIG will not be easy to troubleshoot and fix, especially if it is a "3 in 1" ( Arc, TIG, Plasma cutter ? ), and we don't have any data or parts. Initially, I'd try to contact the dealer where you bought it. The 230 volts you saw from earth clamp to arc lead is way too high. Was that AC or DC ? It should be about 50 to 80 VDC.
Most inverters start with a full-wave rectifier across the mains, with smoothing capacitors, giving about 325 VDC. Some large semiconductors chop this up into high-frequency AC, and then a ferrite-core transformer drops this to low voltage, high current AC, followed by more rectification back to DC for the arc or TIG torch. Please only troubleshoot these stages if you are confident working around live AC mains voltages.

 

[glanzav.tee]

its got 2 rectifiers both seem ok tested with ohms meter cannot remember which it was, but the 40amp relays dont work i may take some pictures with a digi cam to show more indepth

 

[glanzav.tee]

checked transformer thermal fuse blown but replaced temprary with a loop but ordered the thermal fuses so just to test and get it working i've got to look again to find the culprit any suggestions

 

[glanzav.tee]

found 2 dead rectifiers will replace 2moz now

 

[glanzav.tee]

An inverter TIG will not be easy to troubleshoot and fix, especially if it is a "3 in 1" ( Arc, TIG, Plasma cutter ? ), and we don't have any data or parts. Initially, I'd try to contact the dealer where you bought it. The 230 volts you saw from earth clamp to arc lead is way too high. Was that AC or DC ? It should be about 50 to 80 VDC.
Most inverters start with a full-wave rectifier across the mains, with smoothing capacitors, giving about 325 VDC. Some large semiconductors chop this up into high-frequency AC, and then a ferrite-core transformer drops this to low voltage, high current AC, followed by more rectification back to DC for the arc or TIG torch. Please only troubleshoot these stages if you are confident working around live AC mains voltages.

cheers for more information im confident with mains ac voltage not a noobie in that way lol i do house wiring and im a noob as an electrician do lcd tv repairs but beside that this is a new task for me there was one rectifier actually that was busy but if i supply the power to the top control board i still have the red led showing as if there is a fault which can only mean the control board is dodgy, the thermal fuse was burnt out but looped for now will look for more things

 

[glanzav.tee]

i got a problem when i check from the main board the power for the control board it has dc voltage but my meter says its negative when i have the positive probe on the read wire and negative on the negative any ideas ?