Newbie Wiring needing help! No sound when attaching ground wire to jack [ATL-1SB]

[JimC]

Ok I think I have a wire that has a central core attached to the pot, funnily enough it appears that the other end is partially stripped and tinned so I'll just need to cut it shorter.

NO!
Don't do that.
The blue earth wire needs to be taken off the output jack completely, and that stripped tinned shield wire soldered in its place.


BTW, as a general tip, I don't suggest lightly connecting the wires for testing. Connect them up as you mean to leave them.
Several reasons, but among them are
Once you have it working you really don't want to take it apart again and maybe get it wrong the second time.
It tends to be a lot more fiddly to reconnect wires that have already been soldered to tags that have already been soldered.
Modern plastic based components are prone to melt if overheated, so the fewer times you solder to them the better.
Connecting up less neatly for testing means its more likely something will go wrong.