Re: Need HELP with 2002 Mustang in-dash Radio Power Issues
- From: David M <NOSPAM@xxxxxxxxxx>
- Date: Mon, 05 Sep 2005 12:19:31 GMT
On Mon, 05 Sep 2005 07:05:39 +0000, ironrod rearranged some electrons to
form:
> Well lets see, I've been pushing 'trons through wires for almost 30 years
> now, so I'm reasonably confident that I've got the basics right. In
> extremely cold conditions, approaching absolute zero, resistance drops to
> near nothing. In the real world the hotter the junction of the semi-
> conductor the greater the current flow. Conversely, the lower the
> temperature the less current flow across the junction. Now in the real
> world there is a condition designers have to deal with called "thermal
> runaway" and it is a real problem in high powered circuits that get too
> warm.
That's a different mechanism... the increased temperature knocks more
electrons loose from the semiconductor. OK, technically I guess that
would qualify as "lower resistance" (at least at your meter test points).
> Now jump to the other half of the spectrum where the
> junctions are abnormally cold. Your power supply with its limited
> current might not be capable of generating enough power to meet the
> greater demand caused by the colder junctions.
But that would not occur unless the
temperature is decades below zero.
>Most electronic
> devices are designed to operate at "room temperature". Devices that are
> intended to be used in extreme conditions are built much differently. In
> some cases, I've seen environmental design problems where the best
> solution was to create an artificial environment and use "off the shelf"
> components.
Most automotive electronics is designed to handle a much wider range
of temperature than consumer electronics.
> Now, you never did mention if you lived in a cold climate or not, if you
> don't then obviously the problem can't be cold soaking.
I'm not the OP. But I would still suspect a simpler solution,
like a loose connector contact (heating up and expanding).
Connectors have a higher failure rate than semiconductor
junctions.
>
>
> "David M" <NOSPAM@xxxxxxxxxx> wrote in message
> news:pan.2005.09.04.01.37.56.291728@xxxxxxxxxx
>> On Sat, 03 Sep 2005 16:34:55 +0000, ironrod rearranged some electrons
>> to form:
>>
>> > Where do you live? In extremely cold conditions transistors & IC's
>> > can become "Cold Soaked" that is, the components have become so cold
>> > that
> their
>> > internal resistance has risen to the point that they can no longer
> conduct
>> > electricity.
>>
>> Ummm... where did you get that information from? Oh, I see, you pulled
>> it from your a**.
>>
>> Electrical resistance of metals and most semiconductors goes DOWN with
>> temperature, not up.
>>
>> Commercial semiconductors will perform within specifications from
>> 0-70C. Industrial rated semiconductors will perform within
>> specifications from -40 to 85C; automotive electronics should operate
>> within that range.
>>
>> More likely the problem is a bad connection on the unit.
>>
>>
>>
>> > "MS" <nospam@xxxxxxxxxx> wrote in message
>> > news:BjKRe.4462$oJ2.2836@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> >> When the car heats up under the sun the in-dash radio works fine but
> when
>> > it
>> >> cools down the radio will not power up. I tried replacing fuse
>> >> check
> the
>> >> wire harness etc. but can resolve this issue. Any advice will be
>> >> highly appreciated.
>> >>
>> >> Thanx.
>> >>
>> >> Please drop me a line at vocalglobe//at\\hot mail//dot\\com
>> >> (remove the //\\)
>> >>
>> >>
>> >>
>> --
>> David M (dmacchiarolo)
>> http://home.triad.rr.com/redsled
>> T/S 53
>> sled351 Linux 2.4.18-14 has been up 36 days 22:54
>>
--
David M (dmacchiarolo)
http://home.triad.rr.com/redsled
T/S 53
sled351 Linux 2.4.18-14 has been up 38 days 9:37
.
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