what's too hot?
 

When talking about radio regulators running too hot what does that
mean actually?

Does it mean that your air conditioned radio shack is too hot because
the air conditioner can't keep up with your so and so receiver?

Does it mean that your desk has a hole burned in it where your rig
used to sit?

Does it mean that you can roast marshmellows with it?

Does it mean that when you spit on it it sizzles?

Does it mean that the thing has a long history of failures because the
regulators burn up?

Does it mean some idiot thought the things were running too hot so
came up with some cleverly stupid modification that doesn't really do
anything of value beacuse more than likely the regulator has thermal
protection and folds back the current when it gets too hot?

What in the heck does it mean?

Are there any electrical engineers here that could tell me in a
quantifiable manner what exactly too hot really means?

NEO

what's too hot?
 

N9NEO wrote:

Are there any electrical engineers here that could tell me in a
quantifiable manner what exactly too hot really means?



That's a hard question to answer. The best I can do is 'It depends'.

Junction failure due to heat is of primary concern.

A couple of preliminary papers will get you going in the right direction:

http://www.nasa.gov/offices/oce/llis/0768.html

http://www.ewh.ieee.org/r10/bangalor..._18Mar2005.pdf

or:

http://tinyurl.com/2nz3jh



mike

what's too hot?
 

"N9NEO" wrote in message
oups.com...
When talking about radio regulators running too hot what does that
mean actually?

Does it mean that your air conditioned radio shack is too hot because
the air conditioner can't keep up with your so and so receiver?

Does it mean that your desk has a hole burned in it where your rig
used to sit?

Does it mean that you can roast marshmellows with it?

Does it mean that when you spit on it it sizzles?

Does it mean that the thing has a long history of failures because the
regulators burn up?

Does it mean some idiot thought the things were running too hot so
came up with some cleverly stupid modification that doesn't really do
anything of value beacuse more than likely the regulator has thermal
protection and folds back the current when it gets too hot?

What in the heck does it mean?

Are there any electrical engineers here that could tell me in a
quantifiable manner what exactly too hot really means?

NEO


The common "commercial" acceptable temperature range
for components is 0 to 70 C.

Heat typically shortens the life of components.
Chemical reaction (thus aging) rates typically double for every
10 C increase in temperature.

And if it burns you when you touch it that is not
good either. A general design rule is 60 C. There is
a rule of thumb. If you can leave your thumb on
it then it is 60 C or less.

I would try to keep electrolytics cooler. The electrolyte
is less stable than most of the other materials in electronics.

And in general I'd rather have things below
45 C.

what's too hot?
 

In article .com,
N9NEO wrote:

What in the heck does it mean?

Too hot, in the case of the Kenwood R-1000, is that the power supply
has to be resoldered about every 5-10 years because they're 1) running
too much current through too small connector pins, and 2) used a single
sided PC board and the expansion/contraction of the power transistor
leads breaks the solder joints to the board pads.

In some ways this 25+ year old radio is an engineering feat. It has a
single sided board full of 74S (!) TTL and it doesn't seem to interfere
with itself, or much of anything else, but the power supply section is
not one of it's better points.

And it sounds like they didn't improve those parts much in the years
between that and the R-5000.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

what's too hot?
 

On Jun 16, 8:06 pm, "Ron Baker, Pluralitas!" wrote:
"N9NEO" wrote in message

oups.com...





When talking about radio regulators running too hot what does that
mean actually?

Does it mean that your air conditioned radio shack is too hot because
the air conditioner can't keep up with your so and so receiver?

Does it mean that your desk has a hole burned in it where your rig
used to sit?

Does it mean that you can roast marshmellows with it?

Does it mean that when you spit on it it sizzles?

Does it mean that the thing has a long history of failures because the
regulators burn up?

Does it mean some idiot thought the things were running too hot so
came up with some cleverly stupid modification that doesn't really do
anything of value beacuse more than likely the regulator has thermal
protection and folds back the current when it gets too hot?

What in the heck does it mean?

Are there any electrical engineers here that could tell me in a
quantifiable manner what exactly too hot really means?

NEO

The common "commercial" acceptable temperature range
for components is 0 to 70 C.

Heat typically shortens the life of components.
Chemical reaction (thus aging) rates typically double for every
10 C increase in temperature.

And if it burns you when you touch it that is not
good either. A general design rule is 60 C. There is
a rule of thumb. If you can leave your thumb on
it then it is 60 C or less.

I would try to keep electrolytics cooler. The electrolyte
is less stable than most of the other materials in electronics.

And in general I'd rather have things below
45 C.- Hide quoted text -

- Show quoted text -

Too hot means if you **** on it and it sizzles, it's too hot!

FC

what's too hot?
 

99 degrees is too hot.


Now relax, please !!!!


James