I just purchased this unit, and it seemed to be working for a couple of weeks; when I turned the knob the light came on and temp went up, although I was having a little trouble keeping the temp steady. Now the knobs don't seem to be working, they are really hard, tight, to turn and no light. It's like all of a sudden they just quit. I do have two new wafers coming in the mail. Does anyone have any experience with this incubator that can help me out. I am really frustrated that I can't figure this out. I've not had to squish all of my eggs in to the little giant. I do have a manual that I downloaded, but it really doesn't explain the switches, very well.