Rasa

Thyrotron Powered Spinning Stroboscopic Display?!

If this wasn't so unlikely, I'd not have believed it! What an interesting-sounding system of display... I'd love to see one in operation (from a distance!). This page may take some time to load; due to its interesting nature I have included a lot of pictures.

© Sergei Frolov The actual machine!

© Sergei Frolov RASA in all its glory.

© Sergei Frolov The keyboard and display area..

The name RASA was written with latin symbols (not Cyrillic PACA). This calculator was manufactured in Vilnius (now - republic Lithuania), at the same factory as the Iskra 1122.

© Sergei Frolov Inside, a morass of electronics!

© Sergei Frolov ... and wires!

The Amazing Display!

'The stroboscopic indicator was applied in the computer "RASA". The indication was carried out at the expense of bursts of thyratrons MTX-90 duration in 100 us, which lit curly cross-hatchings in a drum spun at speed of 1500 rev/min. Disadvantages: the large power consumption, noise originating by operation and others.'

^{Translation by Sergei Frolov}

© Sergei Frolov The thyrotron display in action.

© Sergei Frolov The display unit with faceplate removed.

© Sergei Frolov Inside the spinning digit drum.

Keyboard Functions

This is a RPN machine, with three roll-down registers. The keyboard has quite a number of interesting/unusual keys, and the non-obvious ones are shown and described here. Thanks to Sergei Frolov for the translations from the manual!

© Sergei Frolov The keyboard

Light overflow pointer (left) Clear all registers Clear last entered number Repeat Change sign

Display 2nd register Display 3rd register "Divide" key - equivalent to ENTER key on RPN calculators. Enter constant Recall constant Constant-mode indicator