Chinese plasma cutter/tig welder only getting a spark!

[Raylicker]

Hi all, I have an Accurate Tools plasma cutter/tig welder that was working fine. I went to use it the other day and now only getting a slight spark from the gun, also getting a little shock from case.. Getting arc on those two poles inside and don't see any burnt or anything abnormal inside. Attached are some pics of it.  Please anyone some help. Thanks for reading this.https://www.eevblog.com/forum/Smileys/default/scared.gif

[EPTech]

Hi there,

Sounds like the HF pilot arc is working but you do not get the main arc. Many things can cause this. Blown rectifier diodes are the most common.

Try measuring the voltage on the secondary side, while pressing the trigger. Do not measure at the torch or anywhere between the torch and the choke as this will possibly ruine your meter.

You should measure around 70V open circuit. Depends from welder to welder. It wil drop conciderably once you establish an arc.

Be carefull. You are measuring on a high engergy circuit. I advise using clamps to probe what you want to probe, then power on the unit, operate it, and then measure.

Good luck.

[trevatxtal]

Check the relays, common fail point.
Watch them when you press the trigger.