64kB EPROM Adapter

27C256-top.jpgSolderless 64kB EPROM adapter for the Acorn BBC Model B

Introduction

This upgrade for the Model A/B alows a 32kB or 64kB EPROM to be installed in one of the four 16kB ROM sockets. Combine up to four ROM images in a single EPROM and using only one socket. Upto four modules can be installed for a total of 256kB of sideways ROM.

What is a paged ROM?

This adapter is ideal for people who want to keep their BBC as original as possible but expand it to make it more useful. Or people who want a simple plug and play memory expansion for the Model B.

Module Description

This adapter is designed to fit in one of the four ROM sockets on an unexpanded Model B. It has a socket for a 64kB EPROM chip on the top of the board. It provides up to 4x 16kB paged ROMs from one physical socket in the Model B. As it is a simple adapter with no active components it adds no additional current draw to the BBC's power supply unit. Typical use might be to combine BASIC, DFS filesystem and two utility ROM images into a single 64kB EPROM and install it in one socket.

This board is fully compatible with my other BBC memory upgrade boards allowing total flexibility in your BBC upgrades.

Features

  • Solderless - no permanent modifications required
  • Jumperless - no configuration required
  • Occuies one paged ROM socket on a model B
  • Up to 4x 16kB ROM images (64kB total)
  • Simple to install in a few minutes
  • Ultra low power & heat - negligible stress on the power supply

Kit Contents

Installation is very simple, solderless and completely reversible. The kit contains everything needed.

  • 64kB EPROM adapter
  • 2x IC clips for ROM image select lines
  • 2x wires to daisy chain multiple modules
  • Printed step by step instructions

Where to buy?

The modules are available for sale on eBay or direct through this website.

Contact me for more information

More detail