Melott,
Here is an edit from the National Amiga Technical journals:
The RAMSEY and DMAC chips are important A3000 custom chips that, among other things, implement part of the A3000's onboard DMA SCSI host adapter. Nearly all A3000 were delivered with the revision combination of DMAC-02 and RAMSEY-04. The problem with this combination is, the DMAC-02 does not like 68040 boards like the A3640. There are both heat and timing problems. If you are lucky, the tolerances of your DMAC-02 are wide enough to work together with the A3640. If you are not so lucky, SCSI will not work correctly anymore with the A3640 installed.
Your very fortunate your DMAC is either an excellent 02, or you have an 04 in your machine. It's extremely hard to be critical of you, as your knowledge base equals or exceeds most Amiga users I can come in contact with. If you would like a copy of my Amiga technical journals and file database on CD, please let me know. It's over 650 Megabytes on a PC CD, so you'll need to turn off CrossDOS via a shell or command to see the long file names.
