I have a problem with the display-unit.

The display has become dim.
After 1min running the text vanishes completely.
Then I see only the red lines on my display.

I already checked the three fuses near the display-connector with an ohmmeter.
They are all ok.

I made a test with my spare unit.
I changed the display-unit.
The fault is definitely on the display-unit.

Any suggestions ?

Thanks
Andreas