Thanks for your thoughts.
Its not that long ago since i replaced the caps (electrolyte) on the D-Board when i had a blown Q510 VDrive transistor, but i will check again, maybe i missed one.
Anyway i took the following voltages.
IC1503
my reading / value in schematics
1 = 29,4 V / 26,8 V
2 = 1,4 V / 9,6 V
3 = 1,4 V / 9,6 V
4 = 1,0 V / 9,5 V
5 = 0 V / 0 V
6 = 1,2V / 14,4 V
7 = 22,6 V / 14,4 V
8 = 22,6 V / 14,4 V
9 = 29,4 V / 26,8 V
IC1502
1 = 10,8 V / 10,9V
2 = 6,8 V / 6,8 V
3 = 6,8 V / 6,8 V
4 = 6,8 V / 6,8 V
5 = 0 V / 0 V
6 = 9,2 V / 5,9 V
7 = 6,0 V / 5,9 V
8 = 9 V / 5,9 V
9 = 10,8 V / 10,9 V
Q1520
C = 17,5 V / 11 V
B = 4,2 V / 1,8 V
E = 3,6 V / 1,4 V
all while TV is on.
On the attached picture you can see the deformation a little bit