From: srj@key.COM (Scott R. Johnson)
Newsgroups: comp.sys.handhelds
Subject: Re: Which calculator has a long life?  TI or HP?
Keywords: HP28S, Keyboard problems
Date: 7 Oct 92 04:57:49 GMT
Organization: Amdahl Corporation, Advanced Systems, Fremont CA

In article <uj1g.6.0@ibm3090.rz.uni-karlsruhe.de>, uj1g@ibm3090.rz.uni-karlsruhe.de (Marek Tomczyk) writes:
> In article <9uk1RB3w164w@cflav.sublink.org> flavio@cflav.sublink.org (Flavio Casetta) writes:
> 
> >I don't know what improvements made Texas Instruments in this field:
> >I had got a TI 57 for two years (many years ago) but the keyboard was
> >my major complaint: when I pressed the [0] sometimes I got 000, sometimes
> >nothing, sometimes 00, but seldom 0.
> >Therefore I believe they worked hard to enhance keyboard reliability.

That they did.  I used to work in a campus bookstore (CSU, Chico) and
we *WOULDN'T* sell, nor recommend, TI calculators because of their
keyboards.

Here's the story.

The original TI30 and TI57 had reasonably reliable keyboards.
However, when TI came out with the TI35 (and all of its variants)
case/keyboard combination, they changed the keyboard.  The column
information was carried by aluminum wires, and the keys were brass
(albeit plated) discs with dimples designed to touch the wires when
the key was pressed.  That made the contact point a round piece of
metal, touching a different kind of round piece of metal.  Corrosion,
dirt, and repeated use made these keys get bouncy quickly, and with no
keybounce in the calculator, it made use of the calculator, over time,
impossible.  You can identify these calculators by their buttons; they
have buttons at least twice as long as they are high, and are hinged
at the bottom (only the top of the button goes in when you press it).
TI sold the case-keyboard-guts combination to many companies (I have a
flight computer, a Jeppeson NavStar, which is a TI35 with custom guts)

TI really outdid themselves with the TI57-II and TI55-II variants-- we
would get an order of 24 calculators, and approximately 10 would come
in DOA (flaky keyboards) and the other 14 would be back within 1 month
(more flaky keyboards).  We finally dropped the TI line and
concentrated on HP, Sharp, and Casio.

TI eventually re-issued the entire line, with completely different
keyboards.  We ordered a few representative samples, and my boss and I
played bio lab with them, dissecting them mercilessly.  They had
replaced the wire-button arrangement with an arrangement similar to
the Sharp, and it appeared to be more reliable.  The newer calculators
have buttons that float, that is, they aren't hinged at all.  They are
typically larger and squarer, and have more of a "pop" when you press
them.

However, by now, desire/interest in TI calculators had waned, and we
saw no reason to bring in calculators with less features and higher
prices than the ones we originally had.  I don't think they even sell
them now.
 
> Around 1984 I've bought the simple TI 30 calculator. After a while I've had 
> exactly the same problems with the keyboard; not only with the [0] but 
> with nearly all keys. The keyboard was terrible.

This was an older version of the TI35 keyboard.  It lasted longer, but
still would break down (copper-to-copper as opposed to
nickel-to-aluminum).

> Later on I've aquired
> the TI 30 Galaxy. The keyboard has been working perfectly all the time and
> it still works today. 

The Galaxy was one of the ones I dissected; it was the newer design
(most of the newer ones just bumped the roman numeral; the TI-55-II
became the TI-55-III. The Galaxy was different, because it was a new
calculator.)

> >With regard to the HP48 I can tell you only that I am typing on the 
> >keyboard since May 1990 ** every day ** : it never missed a keypress.

We *never* had a problem with a bad HP, no DOAs, no broken keys, not
even bad batteries.  I always recommended them to people, (with the
caveat that you had to be able to *afford* the critter) and taught RPN
to the disbelievers, at the counter, while-you-wait.

> Now I have the HP28S as well. I like it's keys. The whole keyboard works
> nice except of one key: sometimes I have to press it a little harder
> in order to perform a function.

My current calculator...

> 
> Marek Tomczyk
> 
> uj1g@dkauni2.bitnet


-- 
  --srj           A lunatic is merely a minority of one.
       o_O                                                            --Orwell
      =( ) =      ------------------------------------------------------------
        U   Ack!  Scott Johnson  Amdahl Adv. Sys. srj@key.amdahl.com  623-2333
Newsgroups: comp.sys.handhelds