Tyco delay line memory

UvA Computer Museum catalogue nr 93.44

tyco delay line
This memory device has probably been used in a Control Data Corporation Model 711 or 713 alphanumeric display terminal (around 1970). Dimensions 26 * 29 cm, 2 cm high. Underneath the flat aluminium casing a small printed circuit board is mounted with (among other things) a 710 operational amplifier, a 7401 TTL chip, 5 transistors and the system's external connector. The air-tight aluminium cover was removed for this picture.
Visible is the coiled wire about 29 m long. The total delay time is 9819 microseconds. Hence at the maximal clock frequency of 1 MHz, the storage capacity is about 10000 bits.
An explanation of the delay line's operation is provided on a separate page.