Saturday, February 4, 2017

Retro Review: Texas Instruments BA II Financial Calculator (1984)

Retro Review:  Texas Instruments BA II Financial Calculator (1984)

BA II:  Finance Mode

BA II:  Statistics Mode

Company:  Texas Instruments
Mode:  BA II
Year: 1984
Batteries:  2 A76 batteries, or 2 357 batteries
Memory Registers: 1  (only 1, other variables can’t be recalled)

Where’s the Plus?

This review isn’t about the BA II Plus, this is an earlier model.  I purchased the BA II from a box in the Azusa Swap Meet last Sunday (January 28, 2017) for 1 dollar.  Thankfully the previous owner did not leave the old batteries so I didn’t have to worry about battery corrosion.  The previous owner (or one of them) has their name and address on the calculator.  Obviously for privacy issues I took of a couple of stickers containing the address.

The BA II is the second generation of the TI Business Analyst II (released in 1978).  The first generation of the Business Analysist II sold for $40-$45 new.  The Datamath page for the TI Business Analyst II:

Three Modes

The BA II has three modes which cycle by the key sequence [ 2nd ] [ FIX ] (Mode):

‘Profit Mode (no indicator):  Profit Margin mode.  Only the [CST] (cost), [SEL] (selling price), and [MAR] (margin) keys are active.  Solve for the following variables by preceding the key by [ 2nd ].

‘Finance Mode (FIN indicator):  Time Value of Money mode.  Only the [ N ], [ %i ], [ PMT ], [ PV ], and [ FV ] keys are active.  Solve for the following variables by preceding the key by [ 2nd ] or if you are working with beginning of period annuity by using [DUE] instead.  Also, the P/I (Principle and Interest of a single payment) and Acc/Bal (accumulated interest and balance) are also available.

‘Statistics Mode (STAT indicator): Statistics Mode, including linear regression.  The equation is y = a + b*x where a is the intercept and b is the slope.  Mean, deviation, and predictions are also available.

Other Functions
Percent Change:  Δ% has the syntax (new number [ 2nd ] [ % ] (Δ%) old number [ = ])

Fix Modes:  FIX 0-7 will fix the number to that decimal places.  Using FIX 8-9 engage floating mode.

Early Installment Weirdness

1. There is no [CPT] button like it would be prevalent on later Texas Instruments financial calculators. 

2. The sign of cash flow conventions are not followed.  See the example below:

Example:  Calculate the monthly payment of a $174,000 loan.  The loan is for 30 years, 4.65% annual interest, and no balloon payment (FV = 0).  Assume that FIX 2 is in affect and Finance mode is selected.

Remember N is the number of payments and %i is the periodic interest rate (in this case monthly).

174000 [PV]
30 [ * ] 12 [ = ] [ N ]
4.65 [ ÷ ] 12 [ = ] [ %i ]
[ 2nd ] [ PMT ]

The result of 897.21.  (There is no negative sign for outflow like in more current financial calculators, including the HP 12C)

Principal/Interest at the 60th payment:

60 [ 2nd ] [ x<>y ] (P/I)
Returns:  280.11 (principal) [ x<>y ] 617.10 (interest)

Accumulated Interest and Balance after 60 payments:

60 [ 2nd ] [ K ] (Acc/Bal)
Returns: 38804.61 (accumulated interest) [ x<>y ] 158,972.13 (balance)

My recommendation is to write down your answers and key in the time.

Final Verdict

The BA II is a good entry-level financial calculator.  Being it is a 1984, the patience will be required for some calculations. 


This is Edward Shore, 2017

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