Early
Electronic
Calculator
Canon Canola EP151 Calculator

Manufacturer: Canon
Model: Canola EP151
Year: 1971
Form: Desktop
Functions: Basic four, rounding, accumulator
Number of Digits: 15
Display Type: PRI
Logic Technology: SSI,MSI,LSI
Memory Technology: MSI
Diodes: 206
Transistors: 57
Principal ICs: SN3900/4500 Series
IC Complement:Texas Instruments SN3920 (24), Texas Instruments SN3925 (24), Texas Instruments SN3931 (13), Texas Instruments SN4552 (17), Texas Instruments SN4553 (6), Texas Instruments SN4554 (56), Texas Instruments SN4556 (9), Toshiba TM4105
Texas Instruments TMS3314
Texas Instruments TMS4134
(152 total)
Tech. Data Level: 2
Tech. Data Source: RE
Tech. Data Pages: 21
Tech. Data:offline

An early electronic printing calculator. There is no display besides the printer and it doesn't print keypress digits until the entire number is entered.

The printer uses a form of electrographic printing requiring special paper. A rotating stylus scans across the paper delivering high-voltage pulses to burn pixels on the paper. A MOS character generator ROM like those used in CRT computer terminals of the day is used to generate the character pixel patterns.

Notes:
  • Unit will seem dead (no motor activity) until paper is manually fed down into the printer.


- Unit Log -

Serial Number: 200464
Year of Manufacture: 1971 (Integrated circuits stamped with 6927, 7031, 7126, etc.)
Date of Receipt: 08 Dec 2000
Source: Brownlee Office Equipment.
State upon Receipt: Some neon lamps light up. No printer motor activity.


Date: 02 Apr 2002
Procedure: Cleaned.


Date: 02 Apr 2002
Procedure: Portion of reverse engineering done: power supply, printer, clock, memory, character generator.


Date: 05 Apr 2002
Procedure: Filmy gunk on PCB edge connectors cleaned off. Upon reassembly unit seems to function properly, as far as it is possible to test it in the absence of the special paper required. Digit lamps and motor function as would be expected and a scope indicates the pixel stream is present at the printer.


Date: 05 May 2002
Procedure: Reverse engineering complete. Unit is back to being stuck in print more (CC2 presumably).


Date: 27 Dec 2004
Procedure: Half-role of aluminized paper received. Unit mostly functional, addition and subtraction work. Multiplication results in overflow lamp coming on, although the correct result will accumulate into the accumulator. MSD seems to print as '4' when it should be '0'.



  Canon Canola EP151
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