DL2 not putting graphics out

Hi all

In production rehersals which i have 4 DL2's on. All 4 have been running great until 1 decided to only output a white 4:3 image. That one unit outputs the white 4:3 image as soon as the motion layer is at full. Global and graphics layers have no intensity control at all. I can see the unit though CMA and i can see all my content as well as the stock content.

Can anyone help?