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Calculators: Handheld: Commodore F4146R (USA Type I)

Size (approx):

80mm x 150mm x 20-35mm  (w,h,d)
Weight 160g excluding batteries

Power: 6V DC, 4 x AA size internal rechargeable battery pack. It accepts an adapter/charger located on the top side in the middle. Use adapter DC640, 708 or 709, 6 Volts.
Case: Two-piece stippled black plastic case with no evidence of painted trim. Brand name plate is printed plastic strip stuck on its own recess above the display.  Keys in grey, white, red and blue with functions printed silver on the keyboard surround.    The keys are long travel squishy type but work very well.  A matching silver line segregates the financial functions.  Heavily inset and tilted red display filter is convex to work as an additional magnifying lens.  It works quite well giving a large bright display.
Display: 10 + 2 digit red LED with bubble lens and additional linear lens with a thirteenth (and third) digit for negative indication. The extra three exponent digits are .about three quarters of the size of the standard digits.
Features: Four functions plus percentages, change sign, double memory (with two functions each and a summation mode).  Above the line it has powers, reciprocal, register exchange, delta percentages and …. Help manual…
Age: 1976
Manufacturer: Commodore Business Machines, Inc. Palo Alto, California.  Made in USA. Serial No. 062703.
Comments: I think these are lovely as they are so strange now that spreadsheets do all the work for you. With 46 keys is this a button monster or what?  The F prefix of this period indicates a "Financial model", they used "SR" for Slide Rule (or scientific).  Good idea to install rechargeable batteries as this thing would have eaten power.  This is one serious calculator, although the "Made in USA" means assembled at best as all the components and boards are Japanese.  My particular example had a few LED segments off so may have been a bit of an unreliable display.  Logic sound but interesting that such a sophisticated calculator should have no square root, error recovery. To see the UK version click on Commodore F4146R.

Components: 1 x CPU: Commodore GHU-03A 7605 (week code 5 of 1976) 40 pin DIL 0.6" width
1 x unknown IC; Commodore GHU-01A 7605, 16 pin DIL 0.3" width (perhaps a keyboard multiplexer)
2 x display driver ICs: ITT 546A-5N 7601, 16 pin DIL 0.3" width
1 x 14 digit RED LED with bubble lens
1 x transistor
1 x diode
2 x capacitor
3 x resistors
Boards: The keyboard board sits underneath the main cpu board (PCB-200709 Part-1 Rev A) and is joined by a 21-way ribbon cable.  An additional 22-way cable links to the display board.
Construction: Remove the two long screws from the back and the rear section comes off easily by hinging from the bottom.

Logic comments: (CE) is used to cancel the last number entered and (C) to clear the whole calculator.
There is automatic constant on multiply and divide only
Input overflow is suppressed, inputting a thirteenth digit is ignored
Negative numbers are shown with a "-" in the far left (thirteenth) digit thereby allowing full eight-digit negative numbers
Divide by zero shows "E” in the left (twelfth) digit and is not recoverable
Overflow shows no number with "E" in the left (twelfth) digit and is not recoverable
The change sign can be used in mid-number entry
Memory store is not indicated; you have to remember it
The (CMP) key appears to be compute;  to work out 210 use (2)(Yx)(1)(0)(CMP) and it displays "1024"
Without a manual this is the best I can do for the other keys;
(X<>Y) exchanges the registers, (INT) is not integer or intercept as in some of the F range, (delta %) is operated by (4)(D%)(5)(=) "25%".
(N) enters the amount of time periods, (I) the percentage interest, (PV) present value, (FV) future value, (PMT) payment, (DP) could be depreciation?
Interesting, the lower grey keys are designed to be two-key sequences; such as (PER)(WEEK).  If you select one of these keys on its own its acts a a numerical entry key: i.e. (YEAR) = 1, (SEMI) = 2 etc.