I have a 1D4 revision, from one "recent" ( in amiga temporal terms ) batch, running with bppc rev0 ( which is known to be the most problematic one ) and I have had zero timming issues or strange lockups, etc.
Anyway, in tha page of ian stedman, is a guide of how to do the timming fixes to the 1200 mobbos, depending of the revision.
Tell he google "amiga ian stedman" and follow the rabbit
