Glen, thanks for your suggestions. More or less I tried all of that...
I am not worried about autofocus fault per se of course, but it seems to me it is the symptom that can indicate the location of actual fault(s) more precisely...
Anyway, what I really need now is the circuit schematic.. and this is what is probably not (easily) available.
BTW, opening and closing the memory door controls the FET (via main board processor) that I replaced.
Most likely the remaining fault is still on "power board"
http://www.dhcameras.com/canon-eos-4...ment-part-new/
I will also check the other fuses on main board as well (there are 2 more), FU02 is most likely to be blown because of the previous problem with CF card connector (now fixed)