Samsung ln40c530f1f LCD won't turn on - no power led

[zcap]

Hi all.

I have a 40'' Samsung LCD TV that all of a sudden won't turn on. I think at some point it would take a few tries, but would eventually turn on, but now it is dead. No lights, sounds or anything when power is pressed.

Reading here, I thought it may be a power supply (model BN44-00340A). So I took out the power board (pics attached). Nothing obvious, nothing seems burned. All caps seem ok, fuses intact. I plugged the power supply in and tested all the voltages. They seem ok - either 5V or 13V as in the legend printed on the board. Could it work ok out of the TV, but still be bad under load? How can I make sure the power supply is ok?

Any other ideas?

[randtek]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

Hook the power board back up, then disconnect just the cable going from the power board to the main board. (CN1802 on power board end). Backlights should come on, and power supplies should come up to proper voltages. If this happens, 99% sure your power board is good.

[zcap]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

Thanks for reply Randek. Will try the test you suggested next week. If not the power supply, what else could it be, what should I test next?

[zcap]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

Ok, so I tested as Randtek instructed. Unplugged a cable from the main board to the power board. Applied power, backlight came right on. What should I test next? Attached are the pics of the main board.

[beano]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

im stuck at the same point my tv doing the same thing if you find out please let me know

[zcap]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

I never figured it out, my TV is still sitting broken. Power supply seems to be good, so it must be a main board. But replacing it altogether is too expensive, it goes for like $100 on ebay. Will have to trash it unless someone can tell me how to fix it on a component level.

[truep]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

Check the voltages on the three pin regulators on the main board and post them. BTW, keep looking for a new main board, the TV is worth a $100 replacement. if you do, be sure the number on the sticker exactly matches.

[truep]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

BTY, try plugging in all the power connectors, then disconnect the LVDS cable (that goes to the TCON board. Also check and see if there's a cable between the TCON and the Power
supply. If so, tru without that one connected.

[zcap]

Re: Samsung ln40c530f1f LCD won't turn on - no power led

Thanks truep. Can you be more specific where to check the voltages, are these the ones circled?

If I could be sure it is the main board, I'd replace it for a $100.