I did this a number of years ago (20+ years ago). Removed a ram chip from an old broken HDD motherboard.
Soldered to the NEC8201 motherboard with a 3way switch on the rear to select, either of 2 banks from the new chip, or the external Ram Module if I so wished. refer: https://scout.homeunix.org/wib/public/web/nec8201/repainted_nec.htm <https://scout.homeunix.org/wib/public/web/nec8201/repainted_nec.htm> Cheers, TC
