I will try the one I found on Amazon.

My Portable is model 5126, made in late '91 in Cork, Ireland. Even with revisions, the display cable still gets damaged every time you take the display apart...

Mine is slightly worn (about ¾ of a millimetre). As a result I will NEVER take it apart again. Except if the cable is too damaged to work properly, then I'll have to crack it open again... 

I don't know for now, I've never seen the goddamn thing working. I will send the battery to be reconditioned on Tuesday. In the meantime I will try the silicon lube.