Option 1
If you or your husband have some electronic
experience, if you can find and purchase a Service Manual over the internet; It will help you diagnose the source of the problem and fix it by soldering in the new part. The Service Manual will give you circuit diagrams, test points, and part# lists.
Usually, cost under $20. And most cases the new part cost less than $15.
Option 2
http://www.shopjimmy.com/catalogsearch/result/?q=42PC3D-UD
This link sells repacement boards for your TV. If you know which ones the tech said are bad, you can order them and replace the board yourself.
Option 3
Pay $475.00 to get it fixed. :(
I hope I shed some light on the subject for you.