After many problems I got a picture with SCART at my old Toshiba-LCD-TV.
The DRAM is very instabile at the breadboard.
I wrote a loop that fast rewrites the characterset in 16 colors to the screen and tested it on my Commodore 1084s monitor. I think the problem is the dram-refresh at the breadboard. The screen flickers because of the rewrites - but it works!
To convert thy YPbPr output to RGB I built the interface from " Peter Zevenhoven ".