When turned on it has no picture but sound works
if your TV stays on, display glows, but there is no picture, most likely you have faulty t-con board and/or display itself. I've encountered the problem with both lately. I'd start with t-con(display adapter) board. it's not hard to replace and cost around $100 top. If that won't solve the problem, then it's a display panel itself. not an inverter, which is the part of power supply, but panel itself. Before replacing t-con, try to reach display's ribbon cable connectors, plugged into t-con board. disconnect first one and turn set on. If you see half of the picture, the display is bad.
If nothing changes, reconnect that cable and disconnect another one. If you see half of the picture, display is bad. If, still you don't get any picture, that's your lucky day! Display is good, t-con is bad. Replacing the display panel will void any reasonable repair option. Those crooks at "parts distribution' selling displays at the price of your TV, when you bought it: $1,500-2,000+. i don't understand why do they practice rip off. most likely to encourage customers to buy new junk and receive hefty bribes from "peoples republics" to stay in business. Anyway, it's a crazy globalism. that's why our country in default.
good luck with your project,