HP50g spins circles around the TI-89

[jebem]

All good points here IMHO.

I have to express my disliking when looking to HP calculator engineering choices concerning the case/enclosure design in most of their models after the 80's.
By using rivets everywhere instead of screws, it is almost impossible to open the machines for maintenance without leaving traces of it. It will never be the same.

There is one good exception, though: The HP Prime. Easy to open and close using normal tools without leaving any trace of the operation.
(I'm excluding the original serious built Classic HP machines of course - they were built to last and to be maintained when needed).

When we look to what Casio and Texas Instruments have been doing on their most successful models since the year 2000 (Casio Algebra FX series and Texas TI-8x / Nspire series are just a few examples), we see the thinking behind the design choices.

Casio and TI design philosophy orientation allows their machines to be easily maintained, saving money from their customers.

What is the most common causes of failure?
Beverages fell down over the machine keyboard, and forgotten batteries leaking inside the machine.

I have restored so many of these machines in the last years, by just (easily) opening them, clean the offending liquids/acids/bases from the PCB's using the appropriate solutions, washing the case and keyboard plastic materials, and reassembling.
Easy as counting from 1 to 3.
In comparison, maintaining most HP machines is a nightmare.