Toshiba BC-815

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Calculators: Handheld: Toshiba BC-815

		Size (approx):	83mm (max) x 170mm x 26mm (max) (w,h,d) Weight 188g excluding batteries and with strap, 270g including.
		Power:	6.0V DC, 4xAA size batteries. Also accepts adapter (BH-104/BH-108 for 100-120V, or BH-105/BH109 for 200-240V, 5V, 0.5W) through top end left hand side socket. Manganese battery life is quoted as 6hrs, alkaline as 20 hrs. The battery compartment has a ribbon to aid extraction.
		Case:	Sturdy feeling two-piece black plastic case with brushed aluminium front and keyboard surround; both of which sit in their own recesses. A blue and black logo is printed on the top section. An oversized neutral plastic display filter sits slightly proud and gives a bright display with wide viewing angle. The Casio-like keys are soft and squishy, with a soft click but work well.
		Display:	8 digit blue VFD with a ninth digit for negative, memory and error indication
		Features:	Four functions with square root, percentages and four function memory
		Age:	Date of purchase 15 August 1975.
		Manufacturer:	Toshiba (Tokyo Shibaura Electric Co. Ltd.). Made in Japan, Serial number F61949
		Comments:	High quality-feeling calculator, stuffed with components. Top-heavy appearance is due to the large display cover and battery storage area above. The original black plastic case has top-popper closing and a hole to pass the strap through. The logic is appalling - riddle with bugs, no recovery and an annoying input overflow. The factory must have been going at some rate: IC made in June, calculator in the shops and sold by August!

Components:	1 x IC: Toshiba T3189 5F (date code June 1975), 28 pin DIL, 0.6" width black plastic 1 x nine digit VFD, single glass tube, round face 2 x transistors 10 x diodes 8 x capacitors 15 resistors 2 x resistor arrays 1 x voltage converter transformer
Boards:	The keyboard assembly sits lose on top of the main board and is joined by a short 17-way ribbon cable.
Construction:	Remove the battery cover and you will see two lugs on the sides. Push these in and the case will separate. With further gentle levering, the front will lift off, hinging on the bottom edge..

Logic comments:	The (C) key clears the calculator whilst the (CE) key clears the last entry
	Input overflow in not suppressed, keying in a ninth digit causes and overflow which is not recoverable
	The minus sign is shown in the far left (ninth) digit thereby allowing full eight digit negative numbers
	Overflow shows the result with "E" in the far left (ninth) digit and is not recoverable
	Memory store is indicated by the decimal point of the far left (ninth) digit
	Overflow in memory results in an error message as above, but the original memory contents is maintained
	There is only automatic constant on divide and multiply
	Negative square roots are not allowed and display "E" in the far left (ninth) digit with "0." and is not recoverable
	Percentage are calculated to two fixed decimal points on: i.e. 50% of 50 shows as "25.00"
	There is a "battery alarm lamp" that lights the top right hand vertical segment of the ninth digit - thereby draining the batteries even more!
	It suffers the pseudo fixed decimal bug: key in (1)(+)(.)(0)(0)(0)(=) to get "1.000" which remains a three digit fixed decimal until more digits are needed, or you use multiply or divide
	It suffers the negative zero bug: key in (1)(-)(2)(=) to get "-1" now (+)(1) will give "-0"
	It suffers the divide to negative zero bug key in (-)(1)(=) to display "-1" then (/)(1)(0)(=)(=)(=) etc to eventually get "-0.0000000"
	The result of a square root dose not have trailing zero suppression i.e. (9)(SQRT) gives "3.0000000"

Toshiba BC-815 box

This bold box on the left is about the same size as the calculator at 103mm x190mm x 45mm. Both long sides contain stickers with the model number and serial number and the strap line "Toshiba Instant Genius".

Toshiba BC-815 Manual

A brief 8pp two colour manual in English only, with the occasional shaky translation into English.

Printed in Japan with no reference numbers or date. The calculator also came with a similar sized Service Warranty Card, the lower (missing) section of which was posted to their agent; ADM Services Ltd in Sunbury on Thames.

Ref: 1015702-1 M. Om 356 507 Ha

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