Practical answers on identifying, fitting and looking after the internal and external spare parts of a TIG welding unit.
How do I identify the right spare part for my TIG machine?
Start with the rating plate on the machine. It carries the type designation and the serial number, and makers state that the serial number is the proper way to identify parts for a specific machine and should be quoted when you order spares or arrange repairs. The plate also shows the manufacturer, the supply requirements and the performance of the machine.
Then use the parts list in the manual to find the item and part number. If you still have the old part, compare it with the picture and note any numbers on it. When in doubt, quote the type and serial number to our team and check against the manual.
My machine will not power up or keeps cutting out. What should I check before ordering a part?
Check the supply first. Some TIG units run from the mains, while add-on types take their supply from a separate welding power source, so check that the supply is on, that its cable connections are correct and secure, and that it meets the minimum voltage in the manual. A weak supply can cause an unstable arc or poor starting.
Then check the earth clamp and cable connections, the process and gas settings, and the condition of the tungsten. If an overheating light comes on, allow the unit to cool, make sure the cooling air can flow freely, and respect the duty cycle. If the fault remains, contact the maker's service agent.
Which parts on a TIG machine wear most and need replacing?
On the machine itself, the parts most often replaced are those that are handled or plugged in repeatedly: output and control sockets, gas couplings, switches and levers, handles and covers. Internal electronics such as circuit boards more often fail through overheating, damage or electrical faults than ordinary wear.
Makers advise daily checks of the torch parts and the tightness of the welding and earth cable connections, and replacement of damaged or worn parts and cables. Because wear depends on how the machine is used and where, the manual and a careful look at the machine are better guides than a fixed schedule.
How can I tell a socket or connector is loose or overheating?
Welding makers warn that a loose connection causes overheating, rapid deterioration and loss of efficiency, and that power connections can work loose and oxidise with frequent, large changes in temperature. Look for discolouration, melted or distorted plastic, a connector that moves in its socket, or a plug that is warm after welding.
Switch off and isolate the machine, then check that the plug seats and locks fully and clean any dirt from the outside. If a socket shows heat damage or the contacts are worn, have the part replaced rather than just cleaned, and make sure a competent person does any work inside the machine.
What must I do before opening the case of a welding unit?
Isolate it from every supply first, not just switch it off: unplug it from the mains, or for a unit fed from a separate welding power source, disconnect that supply as well. The HSE advises switching off and unplugging equipment before cleaning or adjusting it, and makers say to disconnect before handling electric cables or carrying out maintenance.
Some inverter makers also say to wait for stored energy in capacitors to discharge before opening the case. The wait is machine-specific, so follow the manual. If you cannot be sure the unit is safe, do not open it. Work inside a power source is for a competent person and should be covered by your risk assessment.
Who should fit internal parts such as circuit boards or switches?
Work inside a welding power source should be done by a competent person: someone with the training, skill and knowledge to do the task safely on that type of equipment. The HSE says repairs to electrical equipment should be carried out only by a competent person, and that faulty equipment should be taken out of use and checked. Some makers recommend that regular inspection and cleaning is done by an authorised service agent.
After a repair, the machine should be tested as the maker or the relevant standard requires. The standard for periodic inspection and testing of arc welding equipment also covers testing after repair.