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bluextc89, Technician
Category: TV
Satisfied Customers: 6556
Experience:  Small Business Owner.
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My Samsung LN40B640R3F LED TV wont light up. The TV turns

Customer Question

My Samsung LN40B640R3F LED TV won't light up. The TV turns on normally except the screen never gets bright. If I shine a flashlight at the screen I can see the picture so everything seems to be working normally aside from the lack of backlighting.
Submitted: 4 years ago.
Category: TV
Expert:  bluextc89 replied 4 years ago.
Thanks for stopping by:

This would indicate a bad power supply, or LED inverter board.

I believe the inverter is incorporated on the power supply board in this TV.

Samsung will not see parts direct to the consumer - so your best option is to check eBay or for the exact board in your TV.

Should you have it repaired at a local Samsung Authorized repair center, expect to pay $180-$235 plus 1 hour shop labor.

If you have additional - Just Ask.

Customer: replied 4 years ago.

The sound still comes on so I wouldn't think the entire power board is bad.

Expert:  bluextc89 replied 4 years ago.

It's not. The circuit with the inverter is faulty. Repairing these multi-layer boards with the components compacted into a small footprint is difficult - even for a seasoned technician. That repair is as much as simply installing a new board in most cases.


Samsung advises replacing, rather than repairing, entire boards.

If you open up the set, and can get the board number, I may be able to help you locate a new one.