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
I have an optional wall mount setup, requiring removal of the wall mount hardware from the rear cover - a total of 4 screws.