Electronics

First-generation all-transistor logic with core memory.

Transistors are generally:

  • Telefunken AF 138 PNP Germanium, high-frequency
  • Telefunken AC 122 PNP Germanium, audio freqency

Architecture, Memory & Speed

15 displayed digits and 1 sign indicator lamp

Digit encoding and processing scheme to be determined

Core memory, 8 x 8 x 6 = 384 cores, Register layout to be determined

master clock, core cycle, full-number time - to be determined

Construction

Mechanical construction is complex, intricate and high quality. This is a typical finding in first generation machines from companies previously in the mechanical calculator business.

The electronics are contained on 13 single-sided phenolic circuit boards. The boards have an unusual double ended configuration which requires a card extender and a flying lead extender for in-circuit testing. This is rather inconvenient for troubleshooting.

While the electronics layout is quite compact the remainder of the machine is bulky and the extensive use of steel brackets and fixtures also makes is very heavy. There is a large fan across the width of the machine which adds to weight and bulk but was probably included due to the poor tolerance of germanium transistors to overheating. It's interesting that the whole machine is built to the proportions of a typewriter and is about the same size as a typewriter.

The keyboard is assembled from common industrial microswitches that are contained in an elaborate steel mechanism. Again, this is what one may have expected from a typewriter company that was comfortable with mechanical design but may have been less familiar with electrical parts and switches.