Is the timer on your sun lamp stopping before the time runs out? If yes, then the timer knob has gotten pushed in and simply needs to be popped back into place.
Sometimes during shipping or regular use, the timer knob can get pushed in and cause it to snag on the screw behind it. If this happens, it is an easy fix that takes about 1-2 minutes.
In order to get the timer back into place, you will need something to put behind the knob to push it forward – a butter knife or flathead screwdriver work well.
Start by putting the flat object behind the timer knob. Gently make your way around the knob, slowly wedging it forward as you go. Once the timer gets pushed forward, you should be able to see a gap between the back of the knob and the sun lamp.
If the knob gets completely detached from the unit, simply put it back into place.
Now that the timer is back in place, your sun lamp is ready to go!