LG 37LC7D takes long time to power on

SOURCE: my 32%22 lg tv takes a long time to come on

Most likely the TV has a power supply related problem. It's possible that it maybe a bad capacitor or transformer on the power supply board is starting to fail. The most common thing to go out on flat panel TVs is the circuit board that supply power to the screen. Commonly called a Backlight Inverter Board. It maybe taking it's time to try and power up the screen. But, I can't say it's 100% the problem because I can't actually look at the tv over the internet. I can only make guesses with the symptoms.

You have a few choices:
1. You can try leaving the TV unplugged for 30 minutes so the TV can reset itself.
2. If by chance the TV is still under warranty, go that route.
3. If you have some electronic experience, if you can find and purchase a Service Manual over the internet; It will help you diagnose the source of the problem and fix it by soldering in the new part. The Service Manual will give you circuit diagrams, test points, and part# lists.Usually, cost under $20. And most cases the new part cost less than $15.
4. Pay a TV shop to do the repairs. It maybe costly, but get an estimate of how much they will charge. That way you can decide if it worth repairing or replacing the whole TV.

I hope I shed some light on the subject for you.

SOURCE: i have a lg 37lc7d will shut its self off

When it shuts off does the power light stay on like the unit is still on?If yes,try shining a bright flashlight at the screen and see if you can see any video.If you can your power and main boards are ok.you would then probably need an inverter board or panel.If it is shutting completely off you need a main total assembly since you have already replaced the power supply.The main total assembly is avery common issue on lg lcd tv's.

SOURCE: My tv is a lg

There's a good chance you have failing electrolytic capacitors either in the power section or the inverter section or both.
Any caps in these sections that look bulged at the top, or bulged/leaking at the bottom (look for discoloration of the circuit board around the base of the capacitor) need to be replaced.
If you repeatedly turn it off and on, eventually it'll probably stay on, but every time you turn it off, the unit will get harder and harder to start up until one day it just won't.
Sometimes you have to do the opposite to start it up and unplug it for some time and then try again.

If you aren't tech savvy, don't worry, read the rest of this solution and watch the videos.

If you are handy with a soldering iron and can identify the power supply and/or inverter / FM section for the backlights, an inexpensive handful of capacitors will likely fix you right up.
Match the capacitance on the capacitors. Go over voltage if you can, and still have them fit.
IE - it's not a bad idea to replace a 10V cap with a 16V or 25V or even a 50V, but don't replace a 680uF cap with a 500uF or a 1000uF (unless you are SURE it's only doing supply output ripple filtering,
and even then, you should go OVER, not under the uF rating).

Most of the caps that go are 10V 1000uF or 3300uF.

I found some great videos of the procedure (for many Samsungs with the same issue) on youtube.

http://www.youtube.com/watch?v=Mm51C_RDIZE
http://www.youtube.com/watch?v=BNHHrgX_6cs&feature=related
http://www.youtube.com/watch?v=8l0AUj8QUkg&NR=1&feature=fvwp
http://www.youtube.com/watch?v=Y7b_nTaZYcU&feature=related

As you can see, this issue spans plasma TVs, as well as large and small LCD TVs and monitors, amplifiers, computer power supplies and motherboards, and other electronic equipment.
The parts are cheap, and skill required is minimal.
A great parts source is Digi-Key, and you can order the parts online at www.digikey.com
They typically cost under a dollar a piece plus a flat shipping rate.
The parts usually arrive one business day later.
If you watch the third video, you will see that even someone with no soldering experience can perform these repairs as demonstrated by the woman in the video.