[geeks] well, hell

Kyle Webb kylewebb at beckman.uiuc.edu
Fri Mar 29 17:07:18 CST 2002


At 04:11 PM 3/29/2002 -0600, you wrote:
>On Fri, Mar 29, 2002 at 04:06:54PM -0600, Amy wrote:
> > they suspect that when the car reversed its polarity on the original
> > jump-start, it surged through and killed the alternator (original to the
> > car) and the computer. i'm just waiting to hear what else is toasted :/
>
>Whats wierd is that it worked for most of a day just fine, until the
>alternator finally died (e.g., we were able to take it for a brake job,
>etc, and were out driving around..)

That's not as strange as you might think. It's common for semiconductors to 
work for a time after they've been stressed, and then fail later. We used 
to see that a lot with RS-232 drivers hooked to long cables that had caught 
a surge from a nearby lightning strike. They'd work for a short time, then 
start getting flaky, and die. Also, the voltage probably dropped 
significantly when the alternater died. I've seen a couple of car radios 
with digital readouts that worked when they got full voltage from the 
alternator, but would crap out when trying to run on the battery alone.

Kyle Webb



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