Have sound but no tv picture

That model used the same power supply that the Samsung 940mw uses and when the capacitors go out you get sound but no picture just like you are getting. The repair is easy, you just need to replace the bad capacitors on the power supply board. Here is a link to the repair guide for the 940mw that should help you get your 910 back going, same power supply so the same repair.

http://www.ccl-la.com/blog/index.php/repairing-the-samsung-940mw-lcd-tv/

I hope this helps.