Plonk screen black (very weak)

the screen of my Plonk stays black. More precisely: When I darken the room, I can see a very faint, barely legible display. I changed Rack and isolated it in an empty Palette Case. Beside the screen the module works. I updated the firmware just now, no change (in the dark I can see the module confirming 1.16 at startup)
I did not use the module for some time before mounting it today. I never had a problem before. I did not use it a lot. I bought it in 2019.

The same problem with mine. Did you managed to solve it?

the module is being repaired…