Luka, do you have an oscilloscope? If all supply voltages are ok, next thing to check are waveforms as per timing diagrams here:
http://astroccd.org/2016/10/cam86/#more-1345
It looks like your ADC works as it should.
I made two mistakes while assembling my camera. First, I installed C15 and C16 capacitors because I was looking at schematic and not part list. Those capacitors are not needed , in fact camera was not working with them installed (no H1 output from horizontal driver).
Second mistake was C12, C13 and C14 where I mistakenly put capacitors with 10x needed value. Again, those capacitors control timing and camera produced only garbage.