DISCLAIMER - If you attempt to repair your own set, expect to void any warranty that might still exist. If you do additional damage, it's your own responsibility. Further, you are working with an appliance that is powered from you house mains. There is risk of shock with the potential of death or serious harm. Know what you are doing, and how to work safely with an electrical appliance.
Recently my 3+ year old 40" Samsung LCD TV started taking a long time to start up, with several cycles of relays clicking. In searching the net I found that others were having similar problems. Apparently, Samsung's power supply on several LCD models was somewhat under-designed, with four capacitors that slowly fail over time and which leads to the symptoms in the title.
There are several options for repair: 1) Take the set to a qualified repair shop (est $300 - $500). 2) Buy a new, replacement, power supply ($100 - $175). 3) Replace the offending capacitors ($4.00 - $15.00)
I chose option 3, spending $15.00 for a Samsung repair kit (contains 4-1000 uF, 25V, 105 degree C capacitors and "instructions"). If you want to keep the costs to a minimum, you can order an appropriate set of capacitors from Digi-Key or Mouser for about $0.65 each + s/h.
Tools you need:
Phillips screw driver able to reach recessed screws (about 1" deep)
Soldering Iron for general purpose electronic components.
Note: According to the Samsung repair kit instructions, this repair works with the following models:
Step 1: Remove the back of the set
Place monitor face down on a cushioned table. Remove screws from cover and remove screws from the stand. (If stand is attached)
I have an optional wall mount setup, requiring removal of the wall mount hardware from the rear cover - a total of 4 screws.