I did find WHY my 001 works flawless on G3 B&W and G4s but not on my early 866 dual MDD.
http://archive.digidesign.com/compato/os9/mix/g4agp.html Apple Power Mac G4 MDD "Mirrored Drive Doors" Models — Dual 867 MHz, Dual 1 GHz, and Dual 1.25 GHz and d24 Hardware
Some Pro Tools d24 users (as well as some Digi 001 users) have experienced a system hang on startup with early models of these CPUs. If you have experienced this problem with either d24 hardware or a Digi 001 when connected to one of the "mirrored door" G4s, you should contact AppleCare at 1 800 APL-CARE (within the U.S.). For those customers outside of the US, there should be an AppleCare card included in your Apple product packaging which has the local AppleCare phone number. When contacting AppleCare, customers should refer to the "Digidesign Digi 001 or audio system".
The previous owner of my MDD used it with a HD2, so I think he did not contacted AppleCare...
Was there out a solution for this?
I am lucky to have almost the best pre-MDD CPU daughter board at GHz dual, and I am happy with the 001 on the DA, but maybe other user have a first MDD that can't run 001 or d24 too
My MDD works only with the 001 card. In fact you can use as if it were a ADAT I/O only board.
If I connect the external rack it refuses to boot. And if I made the connection with the computer booted it shuts down.
So a year ago when I had those troubles I decided to let the 001 stay
complete on my G3 B&W or my DA.
Now I have the MDD with an AM-3 and adding a Sonorus STUDI/O