Power connectors
What he said!! This is coming from a W520 workhorse with a number of T61s in various stages of repair. (along with an X60 with SSD/Win7pro/Mint17.1) The yellow power socket on R/T series machines is screwed to the frame and the wiring from it is brought out to a flat plug connected to a header on the planar board (as IBM used to call mobos) No amount of plug abuse is going to break that socket in a hurry!
A new 'proper' Thinkpad would be at the top of my wishlist for a new laptop..