Well, just yesterday I tested a set of RWS (RAM) replacement cards for the IBM 5110 from Patrick Lebbard from Canada - and I'm very impressed. They work well, I had them running for a few hours. Details are described here: https://voidstar.blog/ibm-5110-rws-ram-modern-make-replacements/ or VCF thread https://forum.vcfed.org/index.php?threads/ibm-5110-ram-timings.1253087/ I don't think he plans on becoming a retailer, they've offered up the schematic and such. But he did make these boards for me after I shipped him a set of the base connectors that you need (to adapt them to the 5110's A1 board) that I pulled from a known-broken board. His motivation is that he does have a 5100 also that he's trying to resurrect, so he plans to carry on and make an IBM 5100 version of these modules also (still resolving a few technical differences between them, so it's not working out just yet - but the 5110 version of these I can say seem flawless). Anyway, exciting stuff to see someone technically savvy enough to probe signals and reverse engineer 50+ year old tech! -Steve