What's wrong with high humidity?

M

mm

Guest
To sci.electronics.repair

Most electronic things are rated wrt humidity, but it never mattered
to me before. Now something I might actually want** has a maximum
operating humidity of 80%, and I am pretty sure it gets that humid
here sometimes. (I rarely use my AC and it's broken now anyhow.)

So what's wrong with high humidity? What won't it do, and why? I've
had high humidity all my life for part of the summer, and I don't
remember anything not working.



** Lenovo Multimedia Remote with keyboard N5901
 
mm wrote:
To sci.electronics.repair

Most electronic things are rated wrt humidity, but it never mattered
to me before. Now something I might actually want** has a maximum
operating humidity of 80%, and I am pretty sure it gets that humid
here sometimes. (I rarely use my AC and it's broken now anyhow.)

So what's wrong with high humidity? What won't it do, and why? I've
had high humidity all my life for part of the summer, and I don't
remember anything not working.
Click to expand...

Condensation when the temperature drops.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.
 
On Tue, 11 Jan 2011 02:22:59 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

mm wrote:

To sci.electronics.repair

Most electronic things are rated wrt humidity, but it never mattered
to me before. Now something I might actually want** has a maximum
operating humidity of 80%, and I am pretty sure it gets that humid
here sometimes. (I rarely use my AC and it's broken now anyhow.)

So what's wrong with high humidity? What won't it do, and why? I've
had high humidity all my life for part of the summer, and I don't
remember anything not working.

Condensation when the temperature drops.
Click to expand...
Yep. Also a tendency to increase leakage in hydroscopic and
hydrophilic components such as some film capacitors, phenolic circuit
boards, paper insulators, paper speaker grills, some microphone
elements, and some carbon comp resistors. I designed marine radios
for too many years and water absorption was a serious consideration.
We even designed most radios with vertically mounted boards to prevent
condensation from puddling. In humid climates, there was the added
bonus of mold and mildew. I've had to clean out radios that looked
like a biology experiement gone wild.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
Jeff Liebermann wrote:
On Tue, 11 Jan 2011 02:22:59 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

mm wrote:

To sci.electronics.repair

Most electronic things are rated wrt humidity, but it never mattered
to me before. Now something I might actually want** has a maximum
operating humidity of 80%, and I am pretty sure it gets that humid
here sometimes. (I rarely use my AC and it's broken now anyhow.)

So what's wrong with high humidity? What won't it do, and why? I've
had high humidity all my life for part of the summer, and I don't
remember anything not working.

Condensation when the temperature drops.

Yep. Also a tendency to increase leakage in hydroscopic and
hydrophilic components such as some film capacitors, phenolic circuit
boards, paper insulators, paper speaker grills, some microphone
elements, and some carbon comp resistors. I designed marine radios
for too many years and water absorption was a serious consideration.
We even designed most radios with vertically mounted boards to prevent
condensation from puddling. In humid climates, there was the added
bonus of mold and mildew. I've had to clean out radios that looked
like a biology experiement gone wild.
Click to expand...

I did QA on the PRC-77 manpack radio. One test was a pressure test
under three feet of water, then you had to open the case and look for
any signs of moisture.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.
 
On Tue, 11 Jan 2011 09:48:33 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Tue, 11 Jan 2011 02:22:59 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

mm wrote:

To sci.electronics.repair

Most electronic things are rated wrt humidity, but it never mattered
to me before. Now something I might actually want** has a maximum
operating humidity of 80%, and I am pretty sure it gets that humid
here sometimes. (I rarely use my AC and it's broken now anyhow.)

So what's wrong with high humidity? What won't it do, and why? I've
had high humidity all my life for part of the summer, and I don't
remember anything not working.

Condensation when the temperature drops.
Click to expand...
Thanks.
Yep. Also a tendency to increase leakage in hydroscopic and
hydrophilic components such as some film capacitors, phenolic circuit
boards, paper insulators, paper speaker grills, some microphone
elements, and some carbon comp resistors. I designed marine radios
for too many years and water absorption was a serious consideration.
We even designed most radios with vertically mounted boards to prevent
condensation from puddling. In humid climates, there was the added
bonus of mold and mildew. I've had to clean out radios that looked
like a biology experiement gone wild.
Click to expand...
Thanks also.
 
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