DATAMATH CALCULATOR MUSEUM |
Privileg 861 MD
Date of introduction: | 1976 | Display technology: | Fluorescent |
New price: | Display size: | 8 | |
Size: | 5.4" x 3.3" x 0.8" 138 x 85 x 21 mm3 |
||
Weight: | 4.8 ounces, 135 grams | Serial No: | 76987 |
Batteries: | 2*AA | Date of manufacture: | mth 04 year 1976 |
AC-Adapter: | Origin of manufacture: | Far East | |
Precision: | 8 | Integrated circuits: | TMS1071 (KAΔ7611) |
Memories: | 1 | Displays: | ISE DP89A |
Program steps: | Courtesy of: | Joerg Woerner |
Quelle AG was - together with its arch rival Neckermann - one of the leading department stores in Germany and distributed most of their
electronic products under the "privileg" label. This Privileg 861 MD calculator
caught our attention in 2023 while researching Texas Instruments'
TMS1070 Product family of "single-chip
calculator circuits" and noticing the [+/−] key missing on the keyboard
of the related TI-2550 II. But
a much bigger surprise was the ancient Vacuum Fluorescent Display (VFD) used
with the featured calculator.
Dismantling
this Privileg 861 MD calculator manufactured in April 1976 by an unknown
OEM (Original Equipment Manufacturer) in Far
East reveals a very cost effective design using a single-sided printed circuit
board (PCB) centered around a TMS1071
single-chip calculator circuit connected to a 9-digit VFD, a keyboard assembly
and powered by 2 AA-sized alkaline batteries.
The
TMS1071 is a member
of the
TMS1000 Microcomputer family introduced in October 1974 with the
SR-16 calculator. While the
TMS1000 design was mainly intended for
designs using power-hungry LED displays with external display drivers, uses the
TMS1070 redesigned output drivers for the 11 R-Outputs (Display Scan) and 8
O-Outputs (Segments) that can withstand voltages up to -35 Volts and hence allows
direct operation of low-voltage VFDs.
The
Privileg 861 MD makes fully use of the TMS1070 design and we could identify on the
PCB both the voltage converter to generate a -30 Volts supply for the Ise
Electronic (ISE) DP89A display and the external "pull down" resistors for the R-
and O-Outputs. ISE invented VFDs in 1967, selling most of their displays under the Noritake brand. The
DP89A with its unique bathtub-style glass construction and two 14-pin connectors is one of the first multi-digit VFDs ever made
and branded with the rarer ISE logo.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, February 13, 2023. No reprints without written permission.