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Wang 720B Electronic Calculator

Serial Number 875092

The Wang 700 series programmable calculator, announced in December of 1968, was designed to compete with the HP 9100 calculators that was killing the Wang 300 series calculator sales. The 700 series calculators leveraged work that Wang had done to make a computer to compete with the IBM 360. It is microcoded, like the HP 9100, to maximize the performance and flexibility of the calculator.

The 720 was introduced about 1970. Our 720B has 2k x 8 core memory, twice the amount in the original 700, and sold for $6,800. The 700 calculators are microprogrammed with a 2k x 43 ROP memory. The 720B includes additional microcode to support an IBM Selectric typewriter as a printer or plotter.

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5924 Cassette Read/Write Amps, Nixie Scanner & Decoders

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5926 Keyboard Interface, Core Memory Address Register

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5929 Core Memory Current Source, Temp. Compensation, X & Y Drivers

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6038 2K x 8 Core Memory Array

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5921 Core Memory Sense Amplifiers & Inhibit Drivers, Clock Generator

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5919 Data Bus Routing #1

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5920 Data Bus Routing #2

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5918 4-Bit Arithmetic Logic Unit

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5923 JH, JL, JAD (ROM Address)

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5922 ROM Microcode Decoding

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5927 Operation Mode Logic, Error Lamp Drivers, Display Blanking

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5928 I/O Interface Buffer

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5945 L505 Register Nixie Display Drive

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This is what is under the cover.

The boards front to back are:
5924 Cassette Read/Write Amps, Nixie Scanner & Decoders
5926 Keyboard Interface, Core Memory Address Register
5929 Core Memory Current Source, Temp. Compensation, X & Y Drivers
6038 2K x 8 Core Memory Array
5921 Core Memory Sense Amplifiers & Inhibit Drivers, Clock Generator
5919 Data Bus Routing #1
5920 Data Bus Routing #2
5918 4-Bit Arithmetic Logic Unit
5923 JH, JL, JAD (ROM Address)
5922 ROM Microcode Decoding
5927 Operation Mode Logic, Error Lamp Drivers, Display Blanking
5928 I/O Interface Buffer

5945 L505 Register Nixie Display Drivers are at the right.

The service record from our 720B.
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The Wang calculators stored programs on what looks like an audio cassette. but the oxide on the tape is better.

We recently received a large donation of DEC equipment, and this Wang 612 plotter was included.
The plotter plugs into the Teleprinter port on the calculator, and can send the data to the Teleprinter when not in use.

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