Derek Fountain : ZX Spectrum Lower RAM Module,ZX Spectrum 16k to 48k RAM Memory Upgrade Kit (RAM, Logic Chips, Materials) | eBay,ZX Spectrum 16K to 48K memory upgrade kit,ZX Spectrum 48k Euro 1400 Power Supply – Baked – and thus goes by another day,Fitted a 62256 chip to the board - Grahams Wiki