48sx all indicators on.



I've noticed this morning that all the indicators are on and wont turn off. Any ideas?




If the unit was made in the USA, then it is likely that the LCD is defective. There was a batch of HP48SX calculators that had defective LCDs that eventually either lost columns of pixels and/or had defective annunciators.


Well spot Han, it was made in USA...But, should it shows after 15 years.?



One of the interesting things I heard from HP at the HHC2006 conference last year, is that the graphics calculator (perhaps more so the newer models) may not last as long as the old HP vintage calculators. The explanation given by HP is that using much smaller circuits makes these ultra-fine circuits wear easier as the electrons whiz by.



That's rich. Can they say "Kinpo?"


It's not Kinpo per se, its the newer designs that uses circuits that have much smaller connections. My own conclusion is that if TI uses the same technology, the same will degradation be true for Graphing TI calculators.

The impact is important, because 20 or 30 yars from now they may not be groups like HHC or this museum that still use/play with today's graphing calculators.


Edited: 6 Jan 2007, 10:01 p.m.


It's a real problem. See electromigration.


(...) wear easier as the electrons whiz by.

This reminds me of a question during studies (ages ago, btw).

Someone asked whether or not the accumulator register of the 6502 was made of better quality than the X and Y registers, because it was used so much more often.

just a story ...



There might be some truth to your story. I was very surprised to hear HP's Cyril B (the R&D person) state that comment about tiny circuits wearing out. I guess only sparsely-used graphing calculators will survive into the distant future.



This is the dirty little secret of integrated circuit technology. The current density in those 90nm, or 45nm or whatever wires is incredibly high, orders of magnitude worse than what it was back when line widths were 6um. This is why I expect my HP45 to be chugging along long after a new 50g has died.




I am with you on that 200%



Not "better quality" in the way you are probably thinking, because all of the circuit elements on an integrated circuit share the same "quality". But the transistors may have been physically larger, to drive larger loads. In addition, they may have used larger power supply connections for the same reason. This kind of optimization was done per transistor back in those days, but today design tools automatically pick the drive strength of logic elements for the designer and size the power-supply busses as necessary.




Thanks for the clarification ... I am not an electronics guy ... so thank you for wording it very nicely!


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