Product number (P/N): 103,
Date of intro: 1975, Origin: Bulgaria (List), Dimensions: 137x73x33mm, Weight: 122g,
Power: 6V: (AA x4) + Adaptor,
Display: Type = Display (LED) (List), Digits = 8+1,
Number of keys: 20, #Key-Black: 11, #Key-White: 7, #Key-Yellow: 2,
Keyboard Array (Rows x Columns): 05x04, Keyboard Layout: [M] [C] [CM] [(SquareRoot)] [%] -    [(Division)] -    [x] -    [-] [M-] -  [.] [=] [RM] [+] [M+],
Miscellaneous switch: [ON-OFF],
Classification: / Pocket,
Featuring: Procent, Square root, Logic-technology: VLSI (Very Large Scale Integration), calculator-on-a-Chip, Memories: 1,
Components: 5 Capacitor(s), 4 Diode(s), 17 Resistor(s), 6 Transistor(s), 1 IC(s),
Main Components: ROCKWELL: A5502CB; or; ROCKWELL: A5502PB,
Serie-members: ELKA: 103 (version-1) (Red); ELKA: 103 (version-2) (Yellow),
Collector value: 7.5/10,
Courtesy of: CALCUSEUM (Serge DEVIDTS),
Info: SPIESS Heinz:
I noted that 40-some years ago I had added some additional functions by hand on the keyboard (F, MX, EX,1/x,X^2,+/-).
That reminded me that this must have been my first (but certainly not the last!) experience for ‘modding’ an electronic device:
making available functionality that was built in the device, but hidden from the user.
So, I opened it again to see what I actually had modified then to access the additional functions: It was the solder jumpers on the keyboard PCB which I changed from upper to lower contacts.
From what I know now after searching the WEB, this had changed my ELKA: 103 into an ELKA: 130