Re: Ti-68

[Prev][Next][Index][Thread]

Re: Ti-68

> but one line of
>pixels that make up the digits doesn't work, and other pixels seem to
>randomly turn off when they should be on.

This problem exists in both the TI68 and the TI60X, a shame in
these otherwise excellet calculators. The TI60X is discontinued-
another shame...anyway this problem,believe it or not, is caused
by taking the battery out of the unit (or perhaps by letting the
battery go dead). For some reason having no power applied
to the circuits causes permanent damage to some part of the
IC, probably the display section. I would guess that there is
some sort of reverse charge released into some particularly
vulnerable section of the chip causing permanent damage or
maybe the charge enters a portion of the chip and just sits there
finding no way to exit and thenceforth interfering with the
display voltages. I have found no way to bring one back after
this happens but applying an over-voltage to the battery terminals
(up to 10V, but be careful) temporarily brings the display back,
sometimes some pixels do seem to come back permanently but I
doubt if you'll get the whole display back to normal. It would be
appreciated if anyone with any authoritative information on this
problem , or just someone with a more educated opinion , would
post here.
References: