SWTPC craze

You were lucky!. In the UK, you almost never find interesting stuff in charity shops. We have some ridiculous lawas that mean that all srcond-hand (mains) electrical stuff has to be safety tested by a 'qualified person' and very few charity shops have the ability to do that. My best find in such a place was when I spotted what appeared to be the contact end of an HP41 module in a box of mobile telephone hands-free kits, etc. I extracted it and found it was an HP41 module wire to a box that claimed to be a Hand Held Products EPROM box for the HPt1 (!). Of course I grabbed it. [For non HP calcualtor enthusiasts here, the HP41 had different memory spaces for the user program/data nad for machine code (which officially had to be in HP ROM modules). There was no way to run a machine code program from the user RAM. There were 3rd party solutions for people who wanted to wirte/run machine code programs without having HP make a module, one of which was a unit that took normal EPROM chips and made them appear as a ROM module to the HP41). -tony