Screen shuts down after 15 minutes

Yes, it can be fixed but you have multiple problems. By the time you replace all that has to be you would be better off buying another disposable TV.

If you wish to get some details; check the site linked here. Pull up older posts.
http://electro-medical.blogspot.com/
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD screen are similar, irrespective of its brand and screen size.

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/

If your LCD TV or monitor has stopped working, or is displaying one of the following symptoms, then it's a candidate for some new capacitors
- Flickering screen
- Screen image disappears after several seconds
- Dim screen
- Slow start
- Power LED on, but no picture
- Unusual colors and/or lines
The primary cause of LCD TV and monitor failure is caused by faulty capacitors. You can examine the capacitors in your LCD TV or monitor and actually see if they are bad.
If they appear bulged on top, then they need to be replaced.
New capacitors will solve a host of problems in LCD monitors and TV's and will extend the life of your monitor or TV by several years.
Check the cables, connectors and connections.
Take it to a repair shop.

Shut down, unplug, remove battery, plug in, repeat process.

Unplug both the set and a box or receiver if used with the set, remove from power for several minutes and replug all to see if a reboot will help or not.

Hold the power button in for 10 to 15 seconds for hard shut down if that doesn't work unplug power for about 5 minutes then plug power back in and see what happens

Pioneer Elite Pro rear projection 620HD - Picture is still there but brightness and "white" have faded over years allowing for mediocre viewing when room is dark only. During the daylight picture is visible if viewed straight on and within 15 feet from set. Any suggestions?

tell it to go in normal mode just say sthat when u boot up cuse u shut down inproperley ok might wann buy new video card make sure it pluged in to a hi end power strip ok