Elliott 402

The 402 was the last machine from Elliott Brothers (London) Ltd. to have (thermionic) valves as the

amplifying devices (excluding the 801 & 802 which still used valves in the trigger drive circuits).

The 402E was housed in five cabinets joined in a row and containing standard GPO racking. (For

readers who are not familiar with the GPO (often abbreviated to PO) or General Post Office, at that

time, all telephone communications equipment and mail handling were under control of the

government run GPO). The 402F required two more cabinets to accommodate the floating point

hardware. Each cabinet had a door at the front and back and the end cabinets had end-skins. Thus

the whole formed a fairly air-tight assembly so that the airflow could be directed through the racks to

effect adequate cooling. Each cabinet had an axial extractor fan at the top and each rear door had a

filter assembly at the bottom where fresh air was drawn in.