Toshiba BC-8018

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Calculators: Handheld: Toshiba BC-8018


		Size (approx):	75mm x 142mm x 19mm (max) (w,h,d) Weight 108g excluding batteries.
		Power:	3V DC using 2 x AA size batteries. Also accepts adapter (DC 3V, 0.3W BH-115 or BH-116) through a top side socket on the far left.
		Case:	Slim calculator made from two pieces of matt black plastic. The top houses a black and blue printed metallic sticker with the brand and model number in its own deep recess. There is a raised and flat neutral plastic display filter that gives a bright image. The keyboard surround (which is heavily inset) is brushed aluminium with black printed text for the on/off switch label and descriptor. The keys are squishy and look a lot like Casio keys with their individual escutcheons.
		Display:	8 digit blue VFD with a ninth digit for negative and error indication
		Features:	Four standard functions with percentages, square root and pi.
		Age:	1978
		Manufacturer:	Tokyo Shibaura Electric Co., Ltd., made in Japan, serial number 350557.
		Comments:	Nice simple calculator with a lovely blue colour theme that works well. The logic is sound but let down by the lack of recovery and negative square roots. There was also a model called BC-8018B that look exactly the same externally.

Components:	1 x cpu: NEC D1802C H66556, 28 pin DIL , 0.6" width black plastic 1 x 9 digit VFD: single tube flat face: NEC FIP LD8231 FIP9C5 No. 8E Japan (date code May 1978) 1 x transistor: D545 F7J (the latter may be a 1977 date code) 3 x diodes 7 x capacitors (one on the underside of the main board) 4 x resistors 1 x transformer: 583
Boards:	The main cpu board (101-622A) sits loose in the case with two guides and is attached to the also loose keyboard assembly via a 15-way ribbon cable.
Construction:	Extremely difficult to open as it is held together by very stiff sided lugs - don't bother as damage is highly likely. I started with the top lug that can be seen in the battery compartment - but it took half an hour of levering to eventually pop of the front.

Logic comments:	The (C/CE) key is used once to clear the last entry and a second time to clear the whole calculator
	Overflow on the input of a number is suppressed, typing in a ninth digit is ignored
	There is automatic constant on all four functions
	Negative numbers are flagged by a minus sign in the far left (ninth) digit thereby allowing full eight digit negative numbers.
	Overflow shows the result and "C" (or "E" if negative) in the far left (ninth) digit and is not recoverable
	Divide by zero shows zero and "C" in the far left (ninth) digit and is not recoverable
	Negative square roots are allowed and result in a negative number
	No bugs found

	With the front removed and the keyboard assembly bent back the main cpu board is exposed. Quite a large component count for its late date of 1978. They could have shrunk this design down as the lower space is not used at all except to hold the bent ribbon cable you can see at the bottom.