I have been looking out for a 14MB ram card for my 180 powerbook for quite some time without success. Recently, i started thinking that maybe it would be possible to add the missing ram chips to the existing dram module already in there (4mb)??
When looking at the card itself (borrowed the picture from IFixit: https://www.ifixit.com/Guide/PowerBook+180+Ram+Replacement/7392)
(cant attach an image of it here, but here is a picture of it: https://d3nevzfk7ii3be.cloudfront.net/igi/BiYw1BxQCrmhMOHp.huge)
Afaik, the board is populated with TC518512FTL-80 (Toshiba) chips and these can be bought still.
Would it be as simple as soldering on 6 more of these to gain the full 14MB or is it more complicated than that?