You may try lifting pin 12 & see if you get 1-2V P-P of video on the
pin. You could also try hooking in composite video at TP 6 from a DVD. Just
be sure to use isolation !
I just dont see having a run of bad ICs but its not impossible.
If it were an expensive power pack then I would suspect bootleg
Chi-Comm crap.
73 Zeno
LFOD !