High frequency is normal (between two points of spark is not small), arc can also be wiped, the current is not small (adjustable). It is difficult to start the arc.
High frequency plate pressing
There may be tungsten or card to the heart is not good, with sandpaper tungsten surface slowly, check whether the replacement of the heart,
That is, there is something wrong with your needle. Some of the machines are just the beginning of the time. The current is unstable and the current is steady
