Operation out of spec is never a good idea.

Gerald



On Thu, Oct 10, 2013 at 4:13 PM, <[email protected]> wrote:

> The answer is going to be that while android works fine on that board and
> the ubuntu build works at room temp but not after a -20 cold soak on THAT
> board, neither one might work on a different board after a -20 cold soak.
>
> This is my personal experience with cold temperature testing on hardware
> and I did a whole lot of that back around the early 1990s.  The problem is
> very likely with the 3.3v power.  The Ubuntu build might touch a feature or
> enable a component that the android build doesn't and you might be right on
> the very hairy edge of having enough 3.3v current available at -20C  to
> make the thing operate with android but not with the ubuntu build until it
> warms up a little bit.  The fact that one works and the other doesn't at
> -20C might just be a fluke of the tolerance build up of all the components
> of that board.  On another board neither one might work. On yet another
> board maybe both will work, BUT (and this is very important) neither one of
> them is guaranteed to work because the components on that board are not
> rated for -20C.  In fact, it might work this week but might stop working at
> -20C next month.  Seriously.  You are probably chasing your tail looking
> for a correctable problem when you are using the hardware outside of its
> design spec.  Yeah, it might work -- sometimes -- under just the right
> conditions -- maybe.  Cold does funny things to semiconductors,
> particularly voltage regulators.  In fact, getting power supplies to start
> was the number one issue in getting gear to turn on after a cold soak at
> maximum rated cold temperature.  Operating at 20 degrees below minimum
> rated low temp is no different than trying to operate at 20 degrees above
> maximum rated high temperature.  It might work -- for a while -- maybe --
> and the results will not be repeatable from one board to the next.  Your
> best bet if you want reliable service is to get someone to build you a
> board with components rated for that environment.
>
>
>
> On Thursday, October 10, 2013 4:50:20 AM UTC-7, Kets wrote:
>>
>> Hi George,
>>
>> Point noted about industrial grade of the beagle board components. But I
>> have not understood why Android build works fine. Any pointers towards this?
>>
>> Regards,
>> Ketan
>>
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