I have a a very strange problem. My TV is a Samsung LE46A558P3F.
It is to do with the backlight settings. If I go into 'menu', and change 'backlight' to anything above 5, the screen cuts out - as in, completely black.
The tv is still on and audio is still fine. I have memorised the remote sequence to turn the backlight back down to 5. Doing so doesn't make the display work again straight away - but by powering off and on, it's working again (with backlight set to 5).
If I pull up the menu and set backlight to 4,3,2,1,0 the screen gets progressively darker, as you'd expect. Going 0,1,2,3,4,5 gets lighter again, as you'd expect. But as soon as you hit 6, the screen gets brighter for just a second then goes black. The only way to get picture again is as described above - doing it 'blind', use the remote to set the backlight to 5 or less, power off and on, tv is fine again. In fact, if you set it to 'dynamic' (which sets the backlight at 10) and power cycle the tv, again you get you get the nice bright picture you'd expect for just a second before going black again.
This is all regardless of input, by the way. All inputs - DTV, Ext1&2, HDMI1&2 behave the same way - will only display anything if backlight is set to 5 or less.
I am an electronics engineer to trade and have no issues with taking my TV apart (it's way out of warranty). I would like some advice, however, if this problem is known to you and if you can advise what the most likely part is that needs to be repaired/changed - the PSU, the mainboard, or the inverter/slave?