Are you making the right ground connection?
You are connecting the ground lead to the + terminal, not the - one?
(that has happened here before)
Not with both the torch and ground connected to the "-" supply.It should have still fired off even with the polarity reversed.....
Not with both the torch and ground connected to the "-" supply.
These little TIG's have a + terminal, a - terminal and a TIG torch plug. What they don't tell you is that the torch plug is internally connected to the - terminal.