My new Apple /// has a strange defect. The char-modes are corrupted whereas the graphics are fine. I can boot a floppy (Apple /// demo). I have reseated all ICs and replaced 2 which were so 'corroded' (blackened Silver pins) that i could noch clean then properly. The PSU is cleaned and checked for the right voltages (less than 5% drift). 2 popped filter capacitors were replaced. I am a little stuck now. Every character on screen has white (green 
) vertical lines that make it impossible to identify the actual character that is displayed.
I will (possibly) post some Images in the coming days...
-Jonas
Problem solved!
... it was one of the 2114 SRAMs from the char-generator.
Since i have 'some' spare parts, i could replace both SRAMs with the period-correct counterparts (1981).
-Jonas