Message #1 Posted by Palmer O. Hanson, Jr. on 12 Sept 2007, 2:03 a.m.
The beginning of the thread "Bugs - Bugs and Bugs" (23 August 2007) asked "Do any of you have lists of the bugs in the other brands ...?"
I have been out of commission for about two months with health problems. I am currently in a watch and wait mode so I will try to belatedly respond to the question with some history of bugs in the TI product line and one bug in the Casio product line. The listing is representative but by no means comprehensive.
I recognize three kinds of "bugs". The first kind includes mechanical and electrical deficiencies. The second kind includes software and mathemattical errors.
The third kind includes characteristics of a machine which Richard Vanderburgh called "unannounced features" and Maurice Swinen called "quirks" . These "bugs" were of interest to users but their use was not always supported by the manufacturer.and sometimes even discouraged by the manufacturer. The TI user community became somewhat obsessed with these unannounced features. Sometimes the results were trivial as when one individual reported that on the SR-52 pressing read followed by simultaneously pressiing B, INV, sin, STO, EE, 4 and 0 would turn on the card reader drive motor.
The random number generator in the first graphic calculator was supposed to yield uniformly distributed random numbers. It yielded random numbers which were not uniformly distributed. The distributionn changed when the calling routine changed. The bug was fixed in the fx-7000GA. (V11N1P8 of TI PPC Notes)
There were anomalies in the trigonometric functions and the logarithmic functions. These were similar to those seen in the original HP-35. For example, in the SR-52 the sine of 89.9999999954 is returned as 1.00000000004. V2N2P1 of 52 Notes)
The keyboard had a severe bounce problem. It was so bad that when the TI-55III became available with an improved keyboard one only had to send in a TI-55II to receive a TI-55III in return.with no questions asked. Unfortunately, the defective keyboard was also used in the ,BA-55, the TI-57LCD and the TI-88.
There was a problem in the statistics routine such that if the user entered 4, 5, 6, 7, and 8 the mean would be displayed as 6 but the value in the machine was actually 6 - 1E-10 ! This was caused by use of a different algorithm for statistics accumulation where, for example, the sum of the input values was not stored, but rather the current mean and the number of entries was stored. V8N1P26-27 of TI PPC Notes).
The memory registers used for the statistics routines cannot be accessed using the published procedures. There was an unpublished procedure for viewing the accumulations which started by pressing and holding the R/S, square root and OFF keys simultaneously. (V8N2P21 of TI PPC Notes). .
Some devices had memory problems such that a stored number would not be correctly recalled. The Service Manual presented a program for testing for this problem. The user community found that some faulty memories would pass the TI test and devised a more thorough test.
Capacitor C-7 which is part of the card reading circuitry was occasionally improperly positioned so that it could be touched by the negative battery pack terminal when the battery pack was in place.
The diagnostic routine in the Master Library module and the Agriculture module would fail if the calculator was in the Eng mode. On other modules with the diagnostic routine an INV Eng sequence at the begining of the routine eliminated the problem. (TI PPC Notes V8N2)
If INV Sum+ is executed with the y value in scientific notation an error would occur vbecause at ehtry to the statistics routine the sign of the exponent would be changed rather than the sign of the y value (Page 7 of the V5N2 issue of PPX Exchange)
The advance publicity for the CC-40 said that it had a 3/4 size QWERTY keyboard which could be used for touch typing. A 3/4 size keyboard is a little small -- adult fingers don't fit kiddy keys -- but the real problem was that the ENTER key was where the right shift key should have been.
The Mathematics module had two programming errors. Thre was an erroneous prompt in the Edit routine and the determinqant of a matrix was occasionally of the wrong sign.
Touch typing was no longer possible. The keyboard was too small and the rows did not have a half key displacement between rows.
The AC 9201 Power Supply could only be connected if the printer was connected.
The two prograqmming errors in the CC-40 Mathematics Module were corrected in the TI-74 Mathematics module.
The AC 9201 Power Supply could only be connected if the printer was connnected.
An ASM routine would successfully convert a program with labels to a program with direct addressing. The INV ASM routine which was supposed to convert a program with direct addressing back to a program with labels did not always work properly.(V13N1P8 of TI PPC Notes) . ,