First, the model number you supplied, KV-34XTR10, is not a 50 inch set but a 43 inch tube set.
Secondly, the symptoms you relate of have audio but no video - or that it comes on late, and gets longer as time goes by, is related most often to failure of the high voltage system. The repair nearly always revolves around the flyback transformer and/or the horizontal deflection amplifier (the horizontal output transistor, for example).
The best repair method is to replace both the flyback and the horizontal output transistor because if only one is replaced it is common for the other to fail soon thereafter.
The repairs will cost around $200 to $300 if you have a local shop complete the job; if you DIY as a project the parts costs are around $35 to $40 for the flyback and $10 to $15 for the HOT. It takes a couple of hours of labor for the person if they have some electronics repair experience; longer if not.
Hope this helps.
PS: If you need a tech service I recommend you this one www.tvrepairjacksonvillefl.com
andrew
September 2012