20 Most Recent Samsung LN40B500 40 40" HDTV LCD TV Questions & Answers

Check to make sure you have 24vdc input

Power supply board most likely source, check for rounded tops on capacitors, a common cause.

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.

probably you have defect mainboard .

Hello, Good day.

It's the problem of overheating in the power supply board of the TV.on the power supply board of the TV there are few capacitors and IC.any of this IC is got short or may be weak.so due to this when you start the TV the current passes from electric outlet to the power supply board of TV.but when the current passes from that weak/faulty part at that time current gets stopped or slow and the board overheats and TV shuts off. this is a common problem faced by many other users too.the possible option to solve this issue is to check the power supply board by a meter and continuity tester and replace the faulty component on the board which is short due to which power supply board is getting overheated.its bit technical job but yes its not at all a costly repair to do or get it done by the technician. for required parts it can be easily available from local electronic hardware shop.
Hope this will help in solving the problem.....

The problem is the LCD panel went bad, it can't be repaired, you have to replace it.

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://electronicshelponline.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.

Caps can fail with no outward signs. It takes a special meter to test them. Your set may have a back light inverter that powers the back lights. When it fails, the picture cant be seen, but you have sound, to check this look for a picture on the screen using a flashlight