I think I messed up my DChdmi/DCdigital installation

and ruined a perfectly fine Dreamcast. Controller port A is not working anymore, the others do work, and all the black colors on screen are messed up, there are blue vertical stripes visible on all black surfaces. The sound and the rest of the picture is ok. I can't get the OSD to show up, is this only possible from port A? I tested for bridges on the video chip, I can't find any. I checked the wires going to 601, 602 and reset. The reset wire is soldered to the resistor next to the testpad, the testpad went to my soldering iron.
Any help would be greatly appreciated.
If only the controller port would work again, that would be great.