DG used
in-house part numbers, very much like IBM and HP did. But I
haven't come across an equivalence list, so if you don't have the
schematics, you're lost.
I vaguely seem to recall I had a DG equivalence list
in the 90's.
Aha! Found a binder labeled "Components Guide" which has an equivalence list for
some discretes in the back, and enough plagiarism from the standard IC manuals in the chip
descriptions to help find the SSI/MSI original chips.
Same thing on the web at