I have a lg tv model # du37lg30. after connecting power cord standbye light flashes from red to green and cannot get the tv to power on

SOURCE: LG LCD TV Standby Light Flashing Red Continuously

I have had this same problem twice in the past 3 months. So far both times I've been able to get it back after a week or two. I'm not sure what works, but unplugging and detaching the antenna and cable and waiting a few days seems to be the key. In both instances, I unplugged it for a few days then plugged it in for a few days and repeated the processes until I eventually got the steady red led. Both times prior to the red led the led would flash red then green and make a clickiing noise for several hours before I was able to get it working again.

SOURCE: My 42"LG 50 TV will not turn on

One important step to see if you are having an internal problem is to perform a power drain.

1. Unplug the product's power cable so that the device is not grounded to the house. Do not simply turn off the power-bar if one is in use.
2. Press and hold in the products power button for 1 minute to release the retained electricity from the capacitors and circuit board. 3. Plug the product back into the wall outlet rather than a power-bar to rule it out of contributing to the problem and turn the device back on.
If this does not work but you are still seeing a LED lit up, there is probably a problem between the TV's power supply and the mainboard and service maybe required.

SOURCE: tv won't turn on - power SUPPLY OK

bad main pcb

SOURCE: LG 42 TV powers up for only a second then goes back out.

Undo the back and see if the fuses are blown. Replace them if they are.

SOURCE: my lg tv (model number 42LH40) won't turn on

There might be an off on switch under the lower right hand corner of the set. (feel for it) and switch it.