Allrighty then, so today i finally found some time to work on the TV again and i checked all the other boards but didn't find any other faults.
While checking the boards i found that one of the flat flex cables that was going to the aforementioned board was damaged and had to be replaced.
I dug around in my box of flax flex cables but didn't find any direct replacement so i made a cable from other bits and pieces.
The cable turned out well and i decided to plug the TV in and see if it works with the fixed cable.
At power up it had a pattern of white noise ( with colors ), which washed out and a moment later the TV came back to life with a "HFMI 1" and a "no signal, check signal cable" on the screen.
All was well untill about 10 seconds later the TV blew again.
The two big IGBTs that i had replaced blew in a way that all three pins are shorted together, just like the first ones that i replaced, the heatsink they were on got warm quite quickly as well.
Also when the image came up on the screen it was not sharp, the edges of rectangles were ever so slightly fuzzy.
So the TV works but i can't keep replacing IGBTs for 10 seconds of operation, i guess i'll have to put some fatter IGBTs?