Friden SBT-10
Key-set Electromechanical Calculator

Manufacturer: Friden
Model: SBT-10
Year: 1964 (introduced 1959)
Functions: Add, subtract, accumulate, multiply, divide
Keypad: Full
Digits: 10/20
Display: Dial

One of Friden's sophisticated S-series mechanical calculators.

Note the base, that's a full-coverage 3/4-inch-thick felt pad.

In their day, machines like this all came with dust covers, which were diligently placed over the machine at the end of the working day. This one has remarkably remained intact.

- Unit Log -

Serial Number: 945881
Year of Manufacture: 1964 (Serial no. age list at the Rauck Friden Web Site).
Date of Receipt: 2000s
Source: SPARC discard
State upon Receipt: Grimy, mould on plastic. Non-functional, stuck in activated state (motor always on).
Status: Jammed.

Date: 2013 Feb
Procedure: Exterior cleaned.

Date: 2013 Feb
Procedure: Multiplier keys removed and cleaned with TSP and alcohol. Orange keypad column bars removed for cleaning. Main keypad and right-side functions keys will not come off. Some in-place cleaning done.

Date: 2013 Feb
Procedure: Main drive shaft can be turned manually with bolt and crank. Carriage can be loosened, ready to silde out, but will not come off because add/subtract shaft is stuck and gears will not disengage.

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Mechanical Calculators