i worked in sony service for almost 20 years. and my product category was TV. i always advised cutomers to stay out of it. and i fixed a lot of TV'S that cutomers tried to fix themselves. all they wound up doing was more damage. there should be a sticker on the back that says "refer service to quailified personel". something to that effect. on TV'S its good advise. you are going into a danger zone. very dangerous!!!!!
what did the picture look like??? was it bright with good color??? or was it dull and fuzzy looking??? if the later it is the tube. when the tube emmission goes down the pic looks bad and the IK circuit shuts off the video drive. if the pic looked good the posibilities are endless. and i worked on a ton that had "sentimental value". sorry but, i recommend a pro here. here is sonys search for repair: http://eservice.sony.com/webrma/web/index.do
you will probably have to pay for an est charge. Gary