Not much help I know..... I had a similar telly JVC LT48C570 it'd switch on and then sometimes the led would blink about once a minute or so giving a click from the speakers, thats all it did. Since I couldn't get the firmware I got a board from Ebay that cleared my problem.
The main board is a T.MS3463S.711 with a LSC480 HN08-8 screen.
I would guess you checked the fuse on the Tcon mine was a badge clone for Curry's and PC world and wasn't listed on JVC site - they didn't want to know. What about the 3.3V supply from the DC-DC converter on the main board?
Dave