I think you are right I don't think its just the cable. Funny if its the LCD
panel with a solid line like that because I would expect faults on an LCD
panel to have just loads of pixels gone or totally blank screen all together
rather than a solid vertical line like that.
As I understand it, the signal goes from the display card through a
multiplexed parallel bus cable ( 16 bit wide from the look of the one on
a Portege of the same age) to the LCD unit, where the individual pixels
are addessed by row & column by the internal display drive circuitry,
more or less as a mapped memory space. A stuck drive transistor or three
on the column addressing would give exactly these symptoms, as would a
problem with the connection internal to the display unit between the
actual LCD & it's support circuitry.
Just a thought. It doesn't help with the cost of a new panel, I know....
Tciao for Now!