I could not seem to turn the power of my HP 9300 printer on and off. What do I do? Most likely the back door of your HP printer isn't locked in place. To fix that you can follow the following steps. 1. Remove the back door. 2. Turn the knob to lock position. 3. Check the white plastic points on the sides of the back door aren't broken. (These tell the printer's sensor the back door is locked in place)
