This looks like the old oxidation of the contacts problem for the screen. It is not a cable problem otherwise the rest of the screen would be faulty.
The trick I personally use is to take a piece of thin-ish card and slide it very, very, very gently along the elastomer material that connects the screen panel to the board. You may also want to spray on a little de-oxit or similar to clean the contacts as you massage the elastomer. You will need to remove the screen PCB from the case (four screws hold it in), then the elastomer strip sandwiched between the board and panel will be visible. I tend to power up the machine when I do this just so I can see which rows/cols are being cleaned, but it is not necessary. The rows appear to be ones controlled on the bottom of the screen towards the left side of the elastomer strip. You may also want to look for any general corrosion around the area. Just be very careful, they do not need to be moved much. I have used this trick on quite a few panels with similar problems and generally it works very well. The other option is to remove the screen PCB from the case and see if the problems clear, sometimes the mere flexing of the screen PCB when it is removed can fix the problem - over time the boards can warp slightly. This happened with the last LCD I repaired, removed the screen to clean the contacts and once it was removed it worked perfectly. Put it back into its case and it has been fine ever since. Quite interesting to put a voice and hand to the email :-D On 7/4/20, 6:03 PM, "M100 on behalf of me" <[email protected] on behalf of> wrote: <SNIP> >Here's a quick vid I made of the screen output. The columns don't really >become apparent until there's a full screen of text on display. <SNIP>
