Panasonic JE-1604U

Date of introduction:  1980 Display technology:  Fluorescent
New price:   Display size:  10
Size:  7.3" x 6.1" x 2.1"
 185 x 156 x 54 mm3
Weight:  11.8 ounces, 334 grams Serial No:  1Y402007
Batteries:  2*D Date of manufacture:  mth 12 year 1981
AC-Adapter:  JL-046, JL-047, or JL-048 Origin of manufacture:  Japan
Precision:  20 Integrated circuits:  TMC1081NL (MBSL 8031)
Memories:  1 Displays:  Futaba 11-BT-16A
Program steps:   Courtesy of:  Joerg Woerner
    Download manual: (US: 2.8M Bytes)

Matsushita Electric Industrial Co., Ltd., founded by Kōnosuke Matsushita in 1918 as a light bulb socket manufacturer and better known under their current name Panasonic Corporation or National brand, is a major Japanese multinational electronics company, headquartered in Kadoma, Osakas. Matsushita introduced already in 1969 with the PANAC-12W (JE-240) their first electronic desktop calculator with 12-digit capability and Nixie tube display joining established Japanese manufacturers like Busicom, Canon, Sanyo, Sharp, Sony and Toshiba. Next important step in Matsushita's calculator line was the sleek Panasonic 1000 (JE-102) introduced in 1971 and based on seven LSI (Large Scale Integration) chips manufactured by Mitsubishi before introducing in 1972 the Panasonic 1010 (JE-1010) with just two Mitsubishi LSI chips and finally switching with the JE-801 and JE-1001 to Texas Instruments' single-chip calculator technology.

This JE-1604U desktop calculator was introduced in 1980 together with its portable twin JE-170U and provides 20-digit arithmetic and a 10-digit display. When the calculated result exceeds 10-digits before the decimal point, the overflow symbol "C" or "E" lights up at the left of the display and the approximate result can be obtained by multiplying the displayed number by 1010.

Dismantling the featured JE-1604U manufactured in December 1981 by Matsushita in Japan for the North American market reveals a cost optimized design based on a single-sided printed circuit board (PCB) centered around a TMC1081NL single-chip calculator circuit connected to the keyboard and powered by two DD-sized disposable Alkaline batteries.

The TMC1081NL 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 Vacuum Fluorescent Displays (VFDs).

The JE-1604U makes fully use of the TMS1070 design and we could identify on the PCB both the voltage converter to generate a -32 Volts supply for the Futaba 11-BT-16A VFD and the external "pull down" resistors for the R- and O-Outputs. A very similar design was introduced already with the TI-2550 II, the first application of the TMS1070 chip.

If you compare this JE-1604U with the JE-170U using an identical TMC1081NL chip, you'll notice a different number of keys and you might ask yourself: Are there even more features and functions available with the TMC1081 chip that neither of the two calculators is using? And how do they control a 10-segment display with just 8 O-Outputs? Hint: Only 9 segments are used with the two calculators. Learn more about Characterization of Single-Chip Calculator Circuits with the DCM-50A Platform.


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Joerg Woerner, December 28, 2022. No reprints without written permission.