[IKC2E51R8]

Only had a quick look and i do think its something in the beam current limiter, just by the way its behaving, I let it run and then turned the text on, when text is on the page number gets darker after a minute, then when text is turned off the whole screen goes dull as if the contrast is turned all the way down affects the whole screen including the OSD, then a second later it returns to normal brightness (Does the same in picture mode if rapidly going from a bright to dark image and vice versa so I think (maybe) a bad cap is drifting in value a bit in the BCL. I'll have to have a proper look when ive more time and energy. Pin 15 of IC7309 is the control pin for the BCL so i might temporarily disconnect it and see if it behaves the same way or not to confirm.