I have such a beast, last played with it ~5 years ago and since then it's sitting in storage. Mine is in French (came from Canada) so I'm kind of interested in updating it to English, if possible - I'll be watching this space.

Floppy connector is proprietary, but I made a simple (passive. and ugly) adapter to normal floppy, I remember connecting one of my 5.25 inch drives so I can read my mid-90s floppies on the PS/1. I think I found all the relevant details on the net, but if they are gone I'll try to dig it and upload a photo / draw a diagram. It'll take a few days, most certainly.

Thanks quicknick

Does it happen to have any spare RAM upgrade module? 😀

I will see if I have around a molex 5V splitter connected to HDD power connector (as that is standard) - to see if it powers both FDD and HDD

also paying attention to the the power passed through the PS/1 FDD cable 😀
https://ps1stuff.wordpress.com/how-tos/ibm-ps … py-replacement/

now, did a bit of digging - looks like the ROM chip used in PS/1 2121 is an AMD AM27C1024-150DC UV EPROM (still have to check if this is the exact ROM chip in my machine [cannot do for now, as it is in storage], but the above is based on similar machine I found the details about on the web).

Not sure if the TL866 MiniTool ROM programmer can also write on this chip - the supported chips seem to cover AM27C1024, so for now I assume it does. Have to order some spare AM27C1024 chips and attempt to write the US ROM on it to test 😀

The earliest estimate to try this on my side is for late August/early September - but if anyone has a similar setup and can test this meanwhile, will be good to know if it works 😀))