Cliff input jack question??

[A string bounce]

Hi, this is my first post here, and sorry it’s a real lame one, I do apologise.
I currently have an unbranded 1 x12 cab that I want to put a Greenback into. At the moment it has a Cliff type input jack mounted to a pcb - unfortunately I can’t work out which is the pos / neg terminals as you can’t trace to the attached speaker wires? So my plan is to purchase a new Cliff jack and do away with pcb……
My ‘Lame’ question is - what lugs do I use? Pos / neg ?? I can’t seem to find any info on the net regarding this?? Any advice much appreciated. Thanks.

 

[GIBSON67]

The tip is positive on a plug so the furthest lug from hole will be positive.

 

[A string bounce]

Thank you!