Unknown board A correspondent, Ken Mardle, has asked me to help identify the circuit boards shown on this page, which could possibly be from an early transistorised computer. Unfortunately I do not recognise them, although their distinctive connectors do look familiar to me. A photo of two of them is shown on the right.

He has five boards each with a paper adhesive label printed as follows:

  1. CE.4 5005114 Iss 3
  2. ST 8 883348 Iss 5
  3. CE.2 5004612 Iss 3
  4. CE.34 5015188 Iss 1
  5. LA 17 808835 Iss 2

Boards 2) and 3) look more-or-less identical in terms of their track layout and component placement although the actual components used on each board appear to be from different manufacturers.

The boards have passive components of British origin: Mullard/Philips "tropical fish" style 100nF capacitors, other plastic film capacitors marked GEC, and resistors marked with Welwyn's (old "W" within an Omega symbol) logo.

Unknown board However, the transistors, which are all marked CS4, are not British. On some boards they are marked SGS-F, while on others they carry a capital "M" marking and RRB (or possibly RR8). SGS was an Italian semiconductor manufacturer. One is shown to the right. The diodes are all marked CS2. On some boards they have a white body with red markings and are manufactured by ITT. On other boards they have a black body with white markings and carry a capital "M" . The similarity of the transistor and diode part numbers suggests that these are 'house codes' which therefore cannot be found in any data book.

Unfortunately none of the components seems to carry a recognisable date code.

Ken and I are both keen to find out more about these boards, so if anyone reading this knows anything about them, please