Bought new drain trough and watched video, When I began disassembly, I noticed the ice buildup around side of evaporator. Used hair dryer to defrost. Hardest part was removing/reinstalling the plastic cover over the evaporator. It has a lining of Styrofoam on the back and when I removed the plastic cover, the Styrofoam stayed on the evap. I very carefully took off the Styrofoam itself trying not to break it. It's probably there for insulation. In that area you have to twist, turn, pull up etc.- tight quarters. Easy to break the Styrofoam. Tip - put the Styrofoam back in the plastic cover before putting the whole cover back in. Video was very helpful.