Sylvania LC420SS8 LCD TV When i turn on tv it turns off with in seconds

Check its main power regualtor board. Replace it as card basis.

This seems to be it, hope this helps
http://www.manualnguide.com/download/manual-guide/sylvania-lc420ss8-owners-manual.html
:)

That is most likely a power supply problem. Check/replace the fuse as needed and try replacing the diodes that form a full bridge rectifier.

hi! i have here a couple of codes for your sylvania TV, just try them, 1046, 1465, hope this helps!!!! goodluck!!!

Because there are so many remotes for Comcast products I am not sure which code(s) is for you, so try this site:www.remotecodelist.com

Good Luck !

try this
http://2getdtv.com/directv/remote_codes.html

Hi there,

I have to LCD TV's and mine does this aswel so its nothing to worry about.

I know how irrating it can be, as i have one in my bedroom and you can hear it when your trying to sleep.

But honestly theres nothing wrong with it, they all do it, its to do with the power!

Please Rate.

Thanks

Simply unplug the set, let it sit for a minute or so, then plug it back in and turn it on. I had a similar problem with the same TV and it is working fine now.

http://www.sylvaniaconsumerelectronics.com/pdf/manual/LC420SS8.pdf

nice TV . heres the manual.

tv stays on for 10 seconds then shuts off