Lg 32ln530b keeps turning on and off

there are noo 'bulbs' on an led tv

So did you check out the various components involved in creating the missing voltages? Transformers, caps, diodes, transistors, etc. Did you get the schematic for the power supply and scope it out?

Things do not just fix themselves - you have to check and probe for clues.

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis. http://electro-medical.blogspot.com/ To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board...

The main power supply regulator section circuit fault. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.
Search the site by type in the "brand name" to your device; in the "Search box at the top right of the display window of the Homepage" to get gathered related posts. .

Most likely the power supply unit
Testing LCD TV Power Supply BoardsSTEP BY STEP

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Line, faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

I have the same problem on my 32LN530B-UA. The fuse is still good. I dont see any blown items in the power supply.
Suspecting that this could be a main board problem?

Poor connections between the antenna and the wire that connects it to the TV is the 99% reason. The other 1% is improper direction when aiming the antenna.

Take the TV back, it should work out of the box. If you still have problem with another new TV, have the line voltage check.

How to fix repair vertical lines on half of LCD tv screen