I have gone all the way up on a few dies for a few minutes. Usually this did not encourage them much. What did work for most dies is power cycling the cube while the controller card runs. There are more steps in Kurt's troubleshooting post that involve resetting the miner. I had to do this about 20-25 times in the first week.

If you reset 25 times and it still doesn't work then you'll be ready to RMA that cube. I had to do this with two of my cubes and a controller card. again with insufficient packaging. I don't know who would think a single cardboard strip would survive transport. Cubes were all over the place in one box, their metal shell bent on some.