Try performing touch switch testing and adjustment.

1. Display the touch switch test screen.
   
   - V10/V9 Standard/V9 Lite model
     Local mode→ [I/O Check] menu → [Touch switches and media] → [Test]
   
   - V9 Advanced model
     Touch switch testing and adjustment can only be performed on the V9100iW and
     V9070iW (analog resistive film type).
   
   1) Turn off power to the V9 series unit.
   2) Slide DIPSW2 to the up position to turn it ON.
   3) Turn on power to the V9 series unit and the touch switch test screen will appear.
   
   
   
2. Perform touch switch testing and adjustment. For more information, click here.
   
   

* On the V9 Advanced model, after completing touch switch testing and adjustment,
   turn off power to the V9 series unit and slide DIPSW2 to the down position to turn it OFF.