spell master Model: Spell master Radio shack 
Battery: 4 x 1,5 V type C
                       
AC adapter:
Year: 1988
                                 
Chip:

Info: The Radio Shack Spellmaster) was manufactured in 1988 and represents the last design iteration of the Speak & Spell family. The printed circuit board (PCB) itself is much smaller than the original Speak & Spell design.

ec 4000Model: EC-4000
Battery: BP6 , BP7
Adapter: AC9131 , AC9132
Year: 1979
Chip: TMC1501          
Info: The Radio Shack EC-4000 does not only look like an early TI-57 Programmable, it's 100% identical.





r spell math radio shackModel: Spell' N 
Battery: 4 x 1,5 V type C
                       
AC adapter:
Year: 1992
                                
Chip:

Info:

te 8000Model: TE-8000
Battery: no
Adapter: AC 110 volt
Year: 1973
Chip: TMS0105         
Info:TE8000 is a four-function desk calculator from 1973, built with a Texas Instruments single-chip processor.


te 8000 1

The calculator is housed in a rectangular plastic box finished in imitation woodgrain.

The main circuit board and the display tube board are fastened to the base with a pair of light metal brackets. A 2-pin mains connector and the power transformer are mounted at the rear of the box, with the power switch attached to the moulded top cover. The transformer secondaries are hard-wired to the circuit board.

The display uses a set of miniature eight-segment vacuum fluorescent tubes, Futaba type DG10R1. (The small eighth segment at the centre right gives a "proper" numeral 4, but the processor only drives the usual seven segments). Eight tubes are used for the numerical display, and one (at the right) for polarity and error indication.

The keyboard is built as a single module and is attached to the main board via a cable and edge connector.

te 8000 2

The TMS-0105 series single-chip processors contain all of the calculator circuitry with the exception of the power supplies and display drivers.

The rather untidy circuit board has a simple power supply at the rear and the TMS-0105 chip in the centre. The anode drivers for the nine tubes are at the left, with the eight segment drivers (seven plus decimal point) at the right. The keyboard attaches to the edge connector at the bottom.