I haven't been able to find much information on this issue, but other Toshiba sets will go into a protection mode. Try unplugging for an hour, replugging the set in to see if you can fully reset. http://aaaateva.com/tv-repair/tv-brands-serviced/toshiba-tv-repair/toshiba-tv-codes/
If you're feeling up to the task, you can break out your trusty multitester, acquire a service manual, and start testing. If not, i'd just contact a local service center.