TV powers on and the screen comes on for about 3 seconds....then the picture disappears but the audio stays on as well as the blue light. I can switch between inputs but the screen does not come on. Trying to figure out if this is the Main power supply or just the inverter. Any help would be appreciated.

If the TV has no picture or sound, but the led turns from red to blue or green that means the mainboard has sent the power supply board the start up signal. The first thing that needs to be done is the voltages need to be checked to the power board. Follow the steps.
1. Hold the (menu) and (vol-) buttons on the side of the TV.
2. While holding the (menu) and (vol-) button on the side of the TV you also need to press the (power) button on the side of the TV (NOT REMOTE).
3. When the blue light comes on and stays on wait 10 seconds then let go of the (menu) and (vol-) button.
4. Wait 30 more seconds. After waiting another 30 seconds you should see some type of picture appear on your screen. — If those steps do not work then you need to unplug your TV for 10 minutes then hold the (power) button on the side of your TV for 60 seconds - plug in and turn your TV on.

If those steps do not fix your problem I would check to see if your device is still covered under a warranty. If not I recommend www.tvrepairpros.com they will find a technician in your area to further assist you.

Hi, Do you have a make and model number for this TV?

Does the audio still work normally? If so uits most likely the inverter board which has failed and you can get a replacement inverter from www.tvcircuitboards.com

Did you check the service manual troubleshooting guide yet. You can try disconnecting the power to the inverter board and see if it will stay on and have sound.
Service manuals:
http://elektrotanya.com/?q=showresult&what=Sharp%20LC37SB24U&kategoria=&kat2=all

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm/

Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague

Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.
Or www.digikey.com just make sure to use caps with low ESR, 105c, high ripple current, long life rating such as PANASONIC FM or FC series.

1. Hold [menu] and [vol-] button on the side of the TV
2. while holding these, press the [power] button on the side of TV (NOT remote)
3. blue light comes ON and stays ON
4. wait 10 seconds then let go of [menu] and [vol-]
5. wait another 30 seconds and some type of picture should appear

I think this is right. I got it from the JVC call centers guys so sorry if I missed or messed up a step.

1. Hold [menu] and [vol-] button on the side of the TV
2. while holding these, press the [power] button on the side of TV (NOT remote)
3. blue light comes ON and stays ON
4. wait 10 seconds then let go of [menu] and [vol-]
5. wait another 30 seconds and some type of picture should appear

After being on a little while, the screen goes black (no audio as well) for 20 to 30 seconds. Green light stays on. Then, picture comes back on and takes a couple of seconds to get up to full brightness. About 5 seconds or so after the video comes back, the audio returns.

Until this morning, has only happened a couple of times a day, now happening more often. About 3 times in last 20 minutes.

KDF-E55A20 is about 3 years old.

my polaroid model #3200  does'nt come on!  the light goes from red to blue and nothing,the picture stays black with no flashing or flickering

it is a brandnew tv, so expected that it is under warranty,, it best for you to return where you bought so the warraty will not void. Big possible of factory deffect.