Agilent E4405B Display Problem

[User2938]

Hello, I recently acquired an Agilent E4405B spectrum analyzer which has a strange quirk ... there are pink/red vertical lines equally spaced across the screen. They are always there, unless a button is pressed, which causes something to be processed (change in settings, change in screen, etc.) at which point they turn back to white (or whatever their normal color is supposed to be) for an instant. However, about 1 second later they return to pink.  Seems like whenever a button signal goes high or low, the display looks as it should for a second or so.  I'm attaching a pic, where the lines are visible in the grid... they are across the entire screen but due to the camera lighting you just can't see them in the button labels.  Anyone know what would cause this and how to fix it?