Can’t Find Intermittent Problem In Electronic Components?
Now you have confirmed that the vertical section is giving intermittent problem because the moment you use the handle of the screw driver to gently knock on the board and the display goes back to normal again. You have spent your precious time to test on the components and hope to locate the bad component but you found all of them to be okay. Next you had replaced all of the components one by one and hope to find out which components that give intermittent problem but again the intermittent problem still exist even though you have try hard to solve it.
If you have replaced all of the components and still could not solve the problem then it is time for you to look at the circuit track for hairline crack. You would be surprise with the help of magnifying glass you could see such a tiny crack in between the circuit line. Some circuit boards were just too thin and easily breaks the circuit line/trace. Get a magnifying glass with the X10 range as you could easily see the crack (if there is a break in the line). Once you have located the break in the line you can always solder a wire (use a small wire) across it to make connection again.