My Mitsubishi VS-50705 is dark on screen, do I need to replace the bulbs to fix it? where to buy the bulbs? Thanks

Replacing the crts in a tv should only be done by a professional servicer . There is high voltage in there that you need to know how to handle.There are many alignments to be done that requires some expensive equipment. I don't mean to be rude. The crts may not be the problem and only by being with the unit and truobleshooting it could a technician determine actually what the problem is. But my advise stands from my experiance that this tv is old and would be a money pit to repair. Replacing the crts in a tv should only be done by a professional servicer . There is high voltage in there that you need to know how to handle.There are many alignments to be done that requires some expensive equipment. I don't mean to be rude. The crts may not be the problem and only by being with the unit and truobleshooting it could a technician determine actually what the problem is. But my advise stands from my experiance that this tv is old and would be a money pit to repair.