Last year I found a decent sized vizio tv at a garage sale for $10, because there was no picture. My dad and I got it, and did a home test to discover that it was the inverter that needed to be replaced. Upon taking the back off, my friend and I found that there are two inverters. How do we know which ones, if not both, to replace, and where could I buy a replacement inverter? Also, would it just be cheaper to have a tv repairman look at it and fix it?