Re: ti-92 died and wont come back to life !!

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Re: ti-92 died and wont come back to life !!

Excerpts from netnews.bit.listserv.calc-ti: 25-Nov-96 Re: ti-92 died and
wont com.. by scott goehring@copper.uc
>
> while this may be true for TIs, it's not true generally.  setting
> aside things like the HCF (Halt and Catch Fire) instruction in the
> 65xx series of processors, it is very easy to immolate a SVGA monitor
> by misprogramming the controller.  see alt.folklore.computers for
> discussion of these sort of things.


As I was writing in my last post that software usually can't hurt
hardware, I thought about the two $950 17" monitors that blew up on me
while I was using the tech support recommended video settings (from the
huge mail order computer company whose name rhymes with "hell"), and I
thought, "probably no one will challenge me on that statement, so I
won't mention computer hardware fiascos like mine." You're right that
PC's aren't too forgiving about things like plugging in HDDs the wrong
way, and lots of other things.


 However, I still assert that if hardware is designed well it will
protect itself from damage most of the time. My current 17" monitor from
Micron Electronis (much better than *ell) just muted the signal when I
was playing around with the video settings and hit one it couldn't
handle. That's because to fry semiconductor stuff, you have to crank the
voltage way up and get a lot of current flowing through the circuit. I
had set the frequency too high, but the signal voltage from my video
card hadn't changed so my monitor's electronis could just decide to
ignore the signal. Depending on how good my monitor is, it may be that
it cannot be damaged unless I do something like use a power amp to put
hundreds of volts across the video-in pins. Then all bets are off. But
no matter how much you tweak the video card, you shouldn't be able to
make it crank up its signal voltage, so the monitor should always be
able to decide if it likes the video signal or not.


Note: Don't try increasing the refresh or whatever with a 14" monitor;
most of them have no protecting circuitry and will spontaneously
combust. In fact, don't play with video settings ever unless you figure
that destroying something is a good learning experience :-)


Oh, and getting to the point: unless the engineers at TI screwed up
royally when they designed the 92, they shouldn't break unless you step
on 'em or drop them in a bathtub. So don't panic when fargo locks them
up. Just take out the batteries. (In fact, if you're feeling lucky you
can try to bring your 92 back to life faster by putting all the
batteries in _backwards_ and turning it on. This _shouldn't_ hurt the
calculator in theory, bacause transistors/diodes/capacitors can usually
withstand 6v applied the wrong way. I don't recommend that anyone do
this but if I had a locked up 92 I'd try it)


-Jonathan






+-----------------------------------------------+
| Jonathan Samuel       jsamuel+@andrew.cmu.edu |
| Electrical and Computer Engineering Student   |
| at Carnegie Mellon University                 |
| http://jsamuel.res.cmu.edu/~jsamuel   -or-    |
| http://www.contrib.andrew.cmu.edu/usr/jsamuel |
+-----------------------------------------------+
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