B3-11
Gold Medal of Exhibition of National Economic Achievement. There are two variants of the B3-11, curiously labeled "Epos 73" and "Epos 73A". Though identical in appearance, the earlier Epos 73 model (1977) has 4 ICs and computing logic like the B3-02 (i.e.: leading zeroes are not removed, calculator has fixed comma). The Epos 73A (1978) has a single K145IP11 IC, and has "modern" computing logic. On the Epos 73, the keys [C] and [CK] have identical function, whereas on the 73A the keys [C] and [CK] are different ([C] is all reset, [CK] is correct entry). Curiously, there is another machine called the Epos 73A (Soviet machines, in general, have avoided duplication of model numbering/naming, implying a centralized register of model names). The mortality rate of the B3-11 appears to be quite high; of the three in my collection to date, none of them work correctly! One, in particular, likes to have power applied for several minutes before working, whilst the others function intermittantly. A good thump usually helps these machines :) The small black button to the bottom right of the display is a power interrupt (there is no other power switch on the calculator). When the display cover was closed, it also interrupted the power (this design was also used in several early western calculators, including the Sanyo ICC-804D). To open the cover and turn on the calculator, one would push the black button. There is a fold-up foot on the back, towards the top, which will let the calculator sit on the desktop at a 10 degree slope. On the foot (on Epos 73A variants) there is room for a hand-engraved price. The display tube consists of eight 7-segment digits, with decimals. A sign/error display at far left can be just seen in the picture (directly under the 2nd and 3rd grille hole). 
Name:
B3-11
Quantity:
1
General
Date of Manufacture:
02-01-1975
Overall Condition:
Good condition
Serial Number:
386
Working Condition:
Fully Working condition
Acquired Date:
05-13-2013