Sound but no picture and then tv turns off..
Your symptom is that you have no picture but you have sound. And then the sound cuts out.
Sony Televisions have a circuit that blanks the video when there is a problem generating a picture. There may be something damaged in the video circuit, or in the video drivers on the CRT boards. Worst case scenario, you may have bad CRT’s in the set.
No matter which is the case, I would recommend that the set be looked at by a qualified technician.
This person could run some checks and lead you to a repair.
I could not recommend that you repair the set yourself.
There is a high risk of electrical shock when dealing with picture tubes and projection sets, as they have tubes that will hold a charge like a capacitor. This charge is around 30,000 volts.
I hope this information allows you to resolve this issue.
If I have helped you, please help me, and rate this Solution with the highest FixYa rating. If you cannot rate this post with the highest rating, then please comment to this post and I will try to help you further.