Cannot switch out from RGBHV DL.2

Suddenly one of my Dl.2's will not switch out of RGBHV mode. I have tried all the usual steps (Dim to 0, wait, switch, restore), but not working. Of course this is the one that is the hardest to access. Need to try to get this working by tomorrow for an event. All other DL.2's are responding. Any tips or alternatives to make the switch. CMA can't from what I can tell.

If it is a hardware issue, what do I check? Would a software reimage help?