Tattoo Machine Troubleshooting 
#A134 Armature bars goes down and stays there when footswitch is pressed.

Short Circuit Troubleshooting Answer # A134
Problem	Armature bar sticks to coil when  foot pedal is pressed.
Because	The electrical circuit is shorted and therefore constantly on.
Check	Solder lugs must not touch the frame.
Why	Electricity will flow through any circuit  that is on.
Cause	A solder lug is bent over and touching  the frame creating a new path  for the electricity.
Remedy	Bend the solder lug out so that it  no longer touches the frame.

Also see  needle insertion in tube.

(Bring up separate labeled parts window) then re-size the new window and drag it to the side so that you can see both windows.