Glad you think it's a bit of a random schematic too I thought it was just me! There's something wrong with the F type socket on the main unit. One tip is definitely gone but the new one and the tweezers start to work fine and hold temp when applied to a cold joint if I wiggle the connector about, so I need to get inside and see how the socket connects to the PCB, I think light exists down this `ere tunnel! Thanks for the guidance
