If you opened it completely down to the boards level, then maybe you have noticed that the pushbuttons are no reparable. They must be changed with new. They are not expensive, but you need some skills for de-soldering the existing ones and re-solder the new replacement. They look like: http://www2.mouser.com/ProductDetail/TE-Connectivity-Alcoswitch/1571218-6/?qs=sGAEpiMZZMvxtGF7dlGNpo%2feXpHuNkK6... And the datasheet : http://www.mouser.com/ds/2/418/NG_CD_157...-122444.pdf says that usually such pushbutton is good up to 1 million operations in normal conditions of temperature, humidity, assuming that is no overpressure or mechanical shock applied. If you have the skills worth to try it given the fact that the lamp is not cheap, but be ready for surprises as: maybe the wires between pushbuttons board and main board to have some problems or even the integrated circuits on the main board.