TI-30 Manual Humor from 1976


No, this post is not glorifying the 1976 TI-30.

I was actually discussing HP calculators with a friend just right now, and I was telling him about the "click" which I have never felt. I then realized, well maybe the TI-30 that I took from my grandmother's house has that same click, so I took it out, and tried punching a few buttons.

It most definitely does not have the click (even pressing a button for an instant will cause it to register 2 or 3 presses) I took the manual out of its incredibley ugly case in order to find the date it was made. I started reading, and one of its features reads:

"Algebraic mode of entry allows you to enter mathematical sequences in the same order that they are algebraically stated"

This is quite obviously a stab at RPN (as by 76, HP had a good many calculators out).

I read on and found this:

"Disposable battery power source provides independence from AC power supplies. You can take weeks of computing power with you wherever you go by simply carrying a few spare batteries."

This is obviously a stab at the rechargeable batteries of the HP's of the time. I showed this to my friend (who perfers his TI's) and he was amazed.

I just found it interesting the ways that companies can make a bad feature sound good.



Hi Ben,

The nice thing about the TI-30 was that it was cheap. TI had much higher quality calculators of superior construction at the time. I have a TI-58C with excellent tactile feedback, although I believe that this is a model that was produced a bit later.

In the TI-30, TI was hardly attempting to compete with HP. It was going after the student market for a basic calculator. This model was roughly the equivalent of an
HP-6S or CASIO-fx260 today. It could handle basic scientific calculations for "Science 101" classes.


My first programmable (way back in 1979) was a TI-58 which I still have but the keyboard is very poor, difficult to use quickly and after five or six years a couple of the keys became very unreliable - had to press very hard to register and then they tended to register 2 or 3 times.

Had the same problems with a TI-30 except that the keys became defective much quicker.

Best, James


Woah, you were lucky, then. I had my TI-59 for a year, and by then 40% of its keys were bouncy and/or needed high pressure to register, plus the card reader was partially broken (it didn't sense anymore when a card was through and just kept on running).

I had it fixed, still under warranty, sold it, and bought a HP-41CV. It has seen heavy use, but it's still working perfectly. Quality really makes a difference.

Cheers, Victor


My first calc was a TI-30 from about 1977 or '78.

Ben stated:


I took the manual out of its incredibley ugly case...

It was denim-colored, as I remember...


"Disposable battery power source provides independence from AC power supplies. You can take weeks of computing power with you wherever you go by simply carrying a few spare batteries."

This is obviously a stab at the rechargeable batteries of the HP's of the time.

Interesting. Mine came with a rechargable 9V battery that quickly lost its ability to accept and retain a charge. I started using disposable 9V cells.

One day, I found myself in electronics class when another cell died. I hooked the TI-30 up to a DC power supply outputting 9.0 V measured by a multimeter. The display started going screwy shortly thereafter, and the TI ended up in the garbage, replaced a year later by a Casio LCD model. I'm still not quite sure what I did wrong; maybe the DC wasn't "clean" (steady).


The TI's reversed their red and black wires... black is positive on many models. Might have been the reason yours blew out.

The TI-30 was the best selling LED calculator of all time. Obviously there was a method to their madness.

My TI-59 still works fine (after card reader repair, of course). Still, I always hated the algebraic entry, and despite years of using the TI-59, RPN was still easy to pick up and use again. Still, the 59 was powerful, and I wrote every computer science assignment twice: once for the mainframe, once for the TI-59. It could do anything that was assigned. (1980)



Ahh, TI30.

Got my TI30 in summer of 1977 (summer of 6th grade). We were on vacation and my dad saw it on sale at Safeway in La Grande, Oregon for $25.95 - it came with a "Student Math Kit" textbook w/some interesting stuff. (That's where I found out about Stirling's Approx. for factorial/gamma... lotta fun.)

It was to replace an APF Scientific. My dad and I were in a ham radio class; he HATED to use shifted functions (never bothered me!). And the APF didn't have base-10 log/10^x functions so there was an extra step involved there too.

My TI30 keyboard (and my TI58's) never bounced. Pretty happy w/em. But not HP :)

But even then I couldn't resist playing w/the HP demos at the store...

Bill W
San Jose CA


Are you familiar with the Mach Number problem which appeared in the HP-67 and HP-97 manuals as a difficult equation which provided justification for choosing RPN over AOS? The accompanying writeup in those manuals emphasized the need to solve the Mach Number problem from the inside out.

Users did not have to work from the inside out to calculate the Mach number on the TI-30 or other AOS machines manufactured by TI. They only needed to have faith in the implementation of the parentheses routines and enter parentheses for brackets, braces and parentheses, remember that the square root must come at the very end, remember that you must add real multiply's where there are implied multiply's, and remember to add an equal after the last large closing bracket to multiply the value in the large outside brackets by five. If they watched the display as they proceeded they would even see most of the intermediate results mentioned in the writeups in the HP-67 and HP-97 manuals! So, the AOS user simply enters the equation in his machine as written and, voila, without any agonizing or analysis to decide where to start the problem, the answer appears in the display. The AOS sequence requires 73 steps. The RPN sequence requires 67 steps on the HP-67, but only 66 on the HP-41 where the square root key is not a second function.

AOS solves the problem the inside out, not because the user asks it to, but because that is how it must be done. With RPN the user must examine the equation and find the proper inside point at which to begin. With AOS the machine essentially does the thinking for the user. Higher order languages such as BASIC and FORTRAN also do the thinking for the user when algebraic expressions are entered.

The reason tbe Mach Number problem solves so nicely on the TI-30 is that the problem does not require pending operations or pairs of parentheses that exceed what the machine allows. The really curious aspect of the selection of the Mach Number equation to demonstrate the power of RPN is that the equation is of the exact level of difficulty which permitted straightforward solution by the least capable of the machines in the TI inventory at the time. If one wishes to make RPN machines look better than the AOS machines in evaluating algebraic expresions one must propose a problem which overwhelms the pending operations capabilities of the AOS machines. All of the above reinforces my impression that whoever selected the Mach Number problem as an example of why RPN was better than AOS really didn't understand AOS. Of course, that isn't very surprising because most dedicated AOS users really don't understand RPN. There really aren't many true "bilinguals".


In the same spirit, I recommend reading a very funny story (at least for a TI fan : ) involving Wozniak and RPN vs AOS. He was working for HP circa 1975 and he tells what happened at the calc lab the day the first AOS TI arrived [TI SR-52?]. Classic.

It's on his website at the end of the this page:

-- Paul Novaes


It is not necessary to start in the middle of the equation and work your way out when using RPN. This restriction exists only when using a stack with a finite size where the number of levels available is less than that required by the problem at hand. If you are using a calculator with an unlimited stack, such as that on an HP-48GX, you can start at the left side and move from left to right, using the RPN stack flow chart as given on page 46, in 'Appendix A Stack Algorithm and Flow Chart', of the HP-45 Owner's Handbook.

If you use an HP-48GX to solve this problem you will need 65 keystrokes and 5 stack levels.

keys keystrokes total keystrokes highest stack level

5 enter 2 2 1
1 enter 2 4 2
.2 enter 3 7 3
350 enter 4 11 4
661.5 / 6 17 5
ls x^2 2 19 4
* 1 20 3
+ 1 21 2
3.5 y^x 4 25 3
1 - 2 27 3
1 enter 2 29 3
6.875 eex 6 x/- enter 9 38 4
25500 * 6 44 5
- 1 45 3
5.2686 x/- y^x 8 53 4
* 1 54 3
1 + 2 56 3
.286 y^x 5 61 3
1 - 2 63 3
* 1 64 2
sqrt 1 65 1

65 total keystrokes, five stack levels needed.


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