sci.electronics.repair@googlegroups.com

Today's topics:

* HP Pavillion disk read failure - 12 messages, 7 authors
http://groups.google.com/group/sci.electronics.repair/t/69cf1664455bf171?hl=en
* tv receivers have puny sound - 7 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/5d73f7ad8fcea692?hl=en
* Power for US hub? - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/ea97df224394d067?hl=en
* Removing smoking smell out of electronics? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/ca206ef62cb0cf13?hl=en
* OT: Lithium Cells Exploding - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/181af8dd8c2e6fde?hl=en

==============================================================================
TOPIC: HP Pavillion disk read failure
http://groups.google.com/group/sci.electronics.repair/t/69cf1664455bf171?hl=en
==============================================================================

== 1 of 12 ==
Date: Sun, Dec 12 2010 10:11 am
From: root

I picked up and HP Pavillion which is just over
one year old. The guy who sold it said it just
needed an new hard disk. Not true. I put a
new drive in it and installed my OS. After an
hour or so the system couldn't read the disk.
I shut it down and what I think is the Southbridge
chip was very hot. It had a small passive heat
sink which I removed, cleaned the surfaces, and
put on fresh conductive paste. I also affixed
a small fan to the heat sink. After this I was
able to run the machine for three or four hours
before the same disk read failures started.

I replaced the power supply with one known
to be good and the problems came back after
three hours or so of operation.

Just now I removed the CPU heat sink/fan and
renewed the heat sink compound. The CPU was
at room temperature, so I don't think this
is the problem.

None of the other components on the motherboard
is even warm to the touch. Even the disk drive
was at room temperature.

I can't think of anything other than heat that
would explain the problem, but then I don't
see how the machine could run for several hours
and without overheating.

Any ideas?

== 2 of 12 ==
Date: Sun, Dec 12 2010 10:29 am
From: root

root <NoEMail@home.org> wrote:
> I picked up and HP Pavillion which is just over
> one year old. The guy who sold it said it just
> needed an new hard disk. Not true. I put a
> new drive in it and installed my OS. After an
> hour or so the system couldn't read the disk.
> I shut it down and what I think is the Southbridge
> chip was very hot. It had a small passive heat
> sink which I removed, cleaned the surfaces, and
> put on fresh conductive paste. I also affixed
> a small fan to the heat sink. After this I was
> able to run the machine for three or four hours
> before the same disk read failures started.
>
> I replaced the power supply with one known
> to be good and the problems came back after
> three hours or so of operation.
>
>
> Just now I removed the CPU heat sink/fan and
> renewed the heat sink compound. The CPU was
> at room temperature, so I don't think this
> is the problem.
>
> None of the other components on the motherboard
> is even warm to the touch. Even the disk drive
> was at room temperature.
>
> I can't think of anything other than heat that
> would explain the problem, but then I don't
> see how the machine could run for several hours
> and without overheating.
>
> Any ideas?

I forgot to add, this is a model a6720y desktop
Pavillion. It has an AMD x4 @2.2GHz, 6Gb of
memory, and no IDE drives.

== 3 of 12 ==
Date: Sun, Dec 12 2010 11:22 am
From: Jamie

root wrote:

> root <NoEMail@home.org> wrote:
>
>>I picked up and HP Pavillion which is just over
>>one year old. The guy who sold it said it just
>>needed an new hard disk. Not true. I put a
>>new drive in it and installed my OS. After an
>>hour or so the system couldn't read the disk.
>>I shut it down and what I think is the Southbridge
>>chip was very hot. It had a small passive heat
>>sink which I removed, cleaned the surfaces, and
>>put on fresh conductive paste. I also affixed
>>a small fan to the heat sink. After this I was
>>able to run the machine for three or four hours
>>before the same disk read failures started.
>>
>>I replaced the power supply with one known
>>to be good and the problems came back after
>>three hours or so of operation.
>>
>>
>>Just now I removed the CPU heat sink/fan and
>>renewed the heat sink compound. The CPU was
>>at room temperature, so I don't think this
>>is the problem.
>>
>>None of the other components on the motherboard
>>is even warm to the touch. Even the disk drive
>>was at room temperature.
>>
>>I can't think of anything other than heat that
>>would explain the problem, but then I don't
>>see how the machine could run for several hours
>>and without overheating.
>>
>>Any ideas?
>
>
> I forgot to add, this is a model a6720y desktop
> Pavillion. It has an AMD x4 @2.2GHz, 6Gb of
> memory, and no IDE drives.
>
you got burned, what Can I say!

My son had a PC that went south when a high performance
video card was installed over the cheaper one that he
had in the PC. It worked and all how ever, the PC would
some times Reset, black out etc.. to the point where it
wouldn't reboot if you didn't let it rest. It turns out that
a support chip on the MB was running very hot with this card
in it.. Remove the card, and it was fine..
There were no options on the card to config for this problem.
Guess the buss speed the card was attempting to operate at was
killing the chip!

Oh well.

== 4 of 12 ==
Date: Sun, Dec 12 2010 11:17 am
From: Nancy Norelli

On Sun, 12 Dec 2010 18:11:13 +0000 (UTC), root wrote:

> Any ideas?

Get your goddamned money back?
--
Don't FUCK with me. I'm tuff. And stupid but don't dare FUCK with me.

== 5 of 12 ==
Date: Sun, Dec 12 2010 11:23 am
From: Meat Plow

On Sun, 12 Dec 2010 18:11:13 +0000, root wrote:

> I picked up and HP Pavillion which is just over one year old. The guy
> who sold it said it just needed an new hard disk. Not true. I put a new
> drive in it and installed my OS. After an hour or so the system couldn't
> read the disk. I shut it down and what I think is the Southbridge chip
> was very hot. It had a small passive heat sink which I removed, cleaned
> the surfaces, and put on fresh conductive paste. I also affixed a small
> fan to the heat sink. After this I was able to run the machine for three
> or four hours before the same disk read failures started.
>
> I replaced the power supply with one known to be good and the problems
> came back after three hours or so of operation.
>
>
> Just now I removed the CPU heat sink/fan and renewed the heat sink
> compound. The CPU was at room temperature, so I don't think this is the
> problem.
>
> None of the other components on the motherboard is even warm to the
> touch. Even the disk drive was at room temperature.
>
> I can't think of anything other than heat that would explain the
> problem, but then I don't see how the machine could run for several
> hours and without overheating.
>
> Any ideas?

Sell it.

--
Live Fast, Die Young and Leave a Pretty Corpse

== 6 of 12 ==
Date: Sun, Dec 12 2010 11:33 am
From: root

Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:
>>
> you got burned, what Can I say!
>

Not really, the computer cost $7. I got 6Gb of DDR2
memory, a sata DVD writer, case and 300w power supply.

== 7 of 12 ==
Date: Sun, Dec 12 2010 12:12 pm
From: Baron

root Inscribed thus:

> I picked up and HP Pavillion which is just over
> one year old. The guy who sold it said it just
> needed an new hard disk. Not true. I put a
> new drive in it and installed my OS. After an
> hour or so the system couldn't read the disk.
> I shut it down and what I think is the Southbridge
> chip was very hot. It had a small passive heat
> sink which I removed, cleaned the surfaces, and
> put on fresh conductive paste. I also affixed
> a small fan to the heat sink. After this I was
> able to run the machine for three or four hours
> before the same disk read failures started.
>
> I replaced the power supply with one known
> to be good and the problems came back after
> three hours or so of operation.
>
>
> Just now I removed the CPU heat sink/fan and
> renewed the heat sink compound. The CPU was
> at room temperature, so I don't think this
> is the problem.
>
> None of the other components on the motherboard
> is even warm to the touch. Even the disk drive
> was at room temperature.
>
> I can't think of anything other than heat that
> would explain the problem, but then I don't
> see how the machine could run for several hours
> and without overheating.
>
> Any ideas?

Check for "Bad Caps" around the chip. Not just high ESR, low or non
existent capacitance. Though I must admit I've seen a few with holes
blown through the encapsulation.

--
Best Regards:
Baron.

== 8 of 12 ==
Date: Sun, Dec 12 2010 1:00 pm
From: Jeff Liebermann

On Sun, 12 Dec 2010 18:11:13 +0000 (UTC), root <NoEMail@home.org>
wrote:

>I picked up and HP Pavillion which is just over
>one year old. The guy who sold it said it just
>needed an new hard disk. Not true. I put a
>new drive in it and installed my OS. After an
>hour or so the system couldn't read the disk.

Let me guess(tm). SATA2 drive?

Look into the BIOS CMOS setup and see if it has any setting for the
SATA drive that look like "ATA compatibility mode". If so turn it on.
I'm finding that some drives need this setting, while others work
without it. Same problem on Dell desktops. No experience with the
a6720y so I can't offer my usual proclamation that everything that HP
made in the last 5 years is junk. The lack of replacement boards on
eBay is a good sign. Usually, when there are a mess of defective
motherboards, the dead ones appear on eBay in an effort to recover
some of the expense of replacement.

Also, move the original drive over to another machine and try the hard
disk drive. Internal is best as you can use S.M.A.R.T. to determine
if it's dead or about to die. You'll need the OS recovery partition
from the drive in order to install on a new drive, or just order the
recovery DVD's.

--
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

== 9 of 12 ==
Date: Sun, Dec 12 2010 1:03 pm
From: Jeff Liebermann

On Sun, 12 Dec 2010 13:00:45 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>Let me guess(tm). SATA2 drive?

Also, make sure you have the SATA data cable shoved into SATA port 0,
that you have that SATA ID enabled in the BIOS CMOS setup, and that
you have it set to boot from that ID.

--
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

== 10 of 12 ==
Date: Sun, Dec 12 2010 2:35 pm
From: D Yuniskis

root wrote:
> I picked up and HP Pavillion which is just over
> one year old. The guy who sold it said it just
> needed an new hard disk. Not true. I put a
> new drive in it and installed my OS. After an
> hour or so the system couldn't read the disk.
> I shut it down and what I think is the Southbridge
> chip was very hot. It had a small passive heat
> sink which I removed, cleaned the surfaces, and
> put on fresh conductive paste. I also affixed
> a small fan to the heat sink. After this I was
> able to run the machine for three or four hours
> before the same disk read failures started.
>
> I replaced the power supply with one known
> to be good and the problems came back after
> three hours or so of operation.
>
> Just now I removed the CPU heat sink/fan and
> renewed the heat sink compound. The CPU was
> at room temperature, so I don't think this
> is the problem.
>
> None of the other components on the motherboard
> is even warm to the touch. Even the disk drive
> was at room temperature.
>
> I can't think of anything other than heat that
> would explain the problem, but then I don't
> see how the machine could run for several hours
> and without overheating.
>
> Any ideas?

Any time you see wonky behavior from a PC, check
for bad caps. Around the processor is a prime
area of concern (ripple currents can be tens of
amps, easily, so ESR becomes a big issue).

You can also check *inside* the power supply for
similar problems.

I started a list of (cap and PC) manufacturers that
I have encountered this problem and gave up as it
became too long to track effectively (some I
just recognize instinctively, now).

Note what the machine is doing at the time (idle vs.
working hard, etc.).

Cold spray (whatever form of politically/legally correct
"freon" is en vogue) can help if you suspect a solid
state device.

The components with heat sinks are probably *expected*
to run warm -- don't be surprised if they *do*! :>

Does a quick cycling of power (completely removed before
being restored) give you another "3 hours" of use? Or,
does the problem come back "quickly" (i.e., if it
is thermal, it should come back quickly; if it is a
software problem, it could take 3 more hours for a
memory leak, etc. to manifest)

== 11 of 12 ==
Date: Sun, Dec 12 2010 3:22 pm
From: root

Jeff Liebermann <jeffl@cruzio.com> wrote:
>
> Let me guess(tm). SATA2 drive?
>

Yes, the drive I used is a Seagate 1Tb Barracuda. I pulled it
from a working system, the drive is known to be good.

> Look into the BIOS CMOS setup and see if it has any setting for the
> SATA drive that look like "ATA compatibility mode". If so turn it on.
> I'm finding that some drives need this setting, while others work
> without it. Same problem on Dell desktops. No experience with the
> a6720y so I can't offer my usual proclamation that everything that HP
> made in the last 5 years is junk. The lack of replacement boards on
> eBay is a good sign. Usually, when there are a mess of defective
> motherboards, the dead ones appear on eBay in an effort to recover
> some of the expense of replacement.

I have a choice of IDE mode, RAID, or AHCI. I have tried both
RAID and AHCI, with no difference in the time before the
read errors begin. Remember, the damn system will run for
several hours with intense disk activity, then I'll start
getting i/o device errors and the disk is unreadable.

== 12 of 12 ==
Date: Sun, Dec 12 2010 3:54 pm
From: root

root <NoEMail@home.org> wrote:
> Jeff Liebermann <jeffl@cruzio.com> wrote:
>>
>> Let me guess(tm). SATA2 drive?
>>
>
> Yes, the drive I used is a Seagate 1Tb Barracuda. I pulled it
> from a working system, the drive is known to be good.
>
>> Look into the BIOS CMOS setup and see if it has any setting for the
>> SATA drive that look like "ATA compatibility mode". If so turn it on.
>> I'm finding that some drives need this setting, while others work
>> without it. Same problem on Dell desktops. No experience with the
>> a6720y so I can't offer my usual proclamation that everything that HP
>> made in the last 5 years is junk. The lack of replacement boards on
>> eBay is a good sign. Usually, when there are a mess of defective
>> motherboards, the dead ones appear on eBay in an effort to recover
>> some of the expense of replacement.
>
> I have a choice of IDE mode, RAID, or AHCI. I have tried both
> RAID and AHCI, with no difference in the time before the
> read errors begin. Remember, the damn system will run for
> several hours with intense disk activity, then I'll start
> getting i/o device errors and the disk is unreadable.
>

I just switched the mode to IDE. The up-time was less
than an hour. I think it is time to salvage what I
can from the machine.

==============================================================================
TOPIC: tv receivers have puny sound
http://groups.google.com/group/sci.electronics.repair/t/5d73f7ad8fcea692?hl=en
==============================================================================

== 1 of 7 ==
Date: Sun, Dec 12 2010 10:41 am
From: "Klaatu"

"Charles" <charlesschuler@comcast.net> wrote in message
news:ie0tn5$9sp$1@news.eternal-september.org...
> This is not a repair question, but I got flamed on the design forum and
> thought that I'd try here. I was labeled a kook and a troll and ... Boy,
> does that group have bunched up underwear!
>
> I have three LCD tvs that work well, but the audio is thin. I know about
> amps and external speakers and surround sound and all of that. Please
> don't recommend external devices, as that is NOT what this post is about.
>
> Is there a technology to build decent speakers into these skinny tv
> receivers? The industry has come up with 3-D, dynamic LED backlighting,
> and other nice features ... but no decent STAND ALONE SOUND.
>
> There is a significant market for flat-panel tvs with decent stand-alone
> sound. Any ideas?

Most brands who market lcd TVs also sell external audio systems, for an
additional cost of course. Already have a good stereo? To bad, no analog
out on most lcd panels, optical out only. If you're REAL lucky, it might
have a mini headphone jack.
Don't hold your breath for better sound on lcd TVs, although LG does offer
some audio enhancements called clear voice. All it does is boost the mid
frequencies.

== 2 of 7 ==
Date: Sun, Dec 12 2010 12:50 pm
From: Jeff Liebermann

On Sat, 11 Dec 2010 17:24:38 -0500, "Charles"
<charlesschuler@comcast.net> wrote:

>Is there a technology to build decent speakers into these skinny tv
>receivers?

If you insist on using the built in speakers, perhaps enhancing what
you have might be more useful. Just add a cardboard megaphone to each
speaker. That will produce the equivalent of a public address
speaker, which will certainly be loud.
<http://en.wikipedia.org/wiki/Horn_loudspeaker>

There are different types, such as muffler exhaust ends:
<http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=280585531612>
cheerleader horns:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400152401444>
oversized funnels, kids toys, police bullhorns, trucker air horns, and
popcorn holders:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200374958577>

Methinks a pair of cheerleader horns would probably work best. Some
consideration for supporting the cantilevered horn will need to be
devised. I suspect a camera tripod support will suffice.

Please note that this is not a new idea:
<http://en.wikipedia.org/wiki/File:His_Master%27s_Voice.jpg>

--
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

== 3 of 7 ==
Date: Sun, Dec 12 2010 3:10 pm
From: "Charles"

wrote in message
news:36cd7734-e65f-4ad0-83df-50f049aad228@o14g2000prn.googlegroups.com...

On Dec 11, 2:24 pm, "Charles" <charlesschu...@comcast.net> wrote:
> This is not a repair question, but I got flamed on the design forum and
> thought that I'd try here. I was labeled a kook and a troll and ... Boy,
> does that group have bunched up underwear!
>
> I have three LCD tvs that work well, but the audio is thin. I know about
> amps and external speakers and surround sound and all of that. Please
> don't
> recommend external devices, as that is NOT what this post is about.
>
> Is there a technology to build decent speakers into these skinny tv
> receivers? The industry has come up with 3-D, dynamic LED backlighting,
> and
> other nice features ... but no decent STAND ALONE SOUND.
>
> There is a significant market for flat-panel tvs with decent stand-alone
> sound. Any ideas?

I read your other thread. Apparently you just want to whine about it.

OK, I am a whiner.

== 4 of 7 ==
Date: Sun, Dec 12 2010 3:12 pm
From: "Charles"

"Wild_Bill" wrote in message
news:8o4No.462810$pX3.51653@en-nntp-11.dc1.easynews.com...

You could have just done a Goog search, but apparently you wouldn't, so many
folks would generally assume that it's a troll post.

Goog for what?

== 5 of 7 ==
Date: Sun, Dec 12 2010 3:12 pm
From: "Charles"

"Michael A. Terrell" wrote in message
news:jvKdnbqdBLDneZnQnZ2dnUVZ_judnZ2d@earthlink.com...

Charles wrote:
>
> This is not a repair question, but I got flamed on the design forum and
> thought that I'd try here. I was labeled a kook and a troll and ... Boy,
> does that group have bunched up underwear!
>
> I have three LCD tvs that work well, but the audio is thin. I know about
> amps and external speakers and surround sound and all of that. Please
> don't
> recommend external devices, as that is NOT what this post is about.
>
> Is there a technology to build decent speakers into these skinny tv
> receivers? The industry has come up with 3-D, dynamic LED backlighting,
> and
> other nice features ... but no decent STAND ALONE SOUND.
>
> There is a significant market for flat-panel tvs with decent stand-alone
> sound. Any ideas?

Yes. You don't have a clue about designing electronics.

Nor do you.

== 6 of 7 ==
Date: Sun, Dec 12 2010 3:57 pm
From: "William Sommerwerck"

>> Yes. You don't have a clue about designing electronics.

> Nor do you.

Mr Terrell is a pretty bright guy. If I needed a super-duper electronics
technician, he's be on my short list.

== 7 of 7 ==
Date: Sun, Dec 12 2010 3:59 pm
From: "Charles"

"William Sommerwerck" wrote in message
news:ie3nhf$11g$1@news.eternal-september.org...

>> Yes. You don't have a clue about designing electronics.

> Nor do you.

Mr Terrell is a pretty bright guy. If I needed a super-duper electronics
technician, he's be on my short list.

His demeanor sucks.

==============================================================================
TOPIC: Power for US hub?
http://groups.google.com/group/sci.electronics.repair/t/ea97df224394d067?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, Dec 12 2010 10:59 am
From: D Yuniskis

Hi Terry,

Terry Pinnell wrote:
> Thanks all, glad I asked, as I hadn't realised it needed such a heavy duty
> supply. At worse, I'll get out to the shed and make one.

Again, it only needs that sort of supply if you have devices that
1) need lots of power (e.g., a laptop disk drive powered from
the USB port) and 2) don;t provide it themselves. Some devices
(e.g., the sort of laptop drive I mentioned) have options for
both. Mice, keyboards, etc. usually rely on the USB port for
their (typically modest) power requirements.

> BTW, if you'll excuse a related question, is it usual for USB ports on the
> front of a PC case to be less reliable than ports on the back? Perhaps
> with lower current delivery? That's my motive for deploying this powered
> hub. An operation that failed from the front worked OK from the back
> (connecting an iPad to run an iTunes sync). That wasn't the only thing I
> changed, so it's not conclusive. But from subsequent googling I've seen
> several suggestions that this difference is a real one.

A lot of this depends on the vintage/manufacturer of the PC.

All bets are off when it comes to an "add in" USB card (which
would typically be USB2 or USB3 and most likely "powered" -- but,
could just as easily be an ancient USB1.1 card, etc.)

Some manufacturers put "good" (fast, powered) ports on the front
of the machine leaving slower ports on back for the keyboard/mouse
and giving the user more flexibility in what he can CONVENIENTLY
plug into the front of the machine. Other machines may be the
exact opposite with the philosophy that the fast devices you are
likely to use will be semi-permanently attached and you'll just
need the front ports for things like thumb drives (modest power
requirements).

The ports *in* keyboards are almost never capable of delivering
and sort of power (I've seen some that won't support a thumb drive).
And, of course, you are limited to the speed of the keyboard's
connection to the PC (in addition to the hub/controller within the
keyboard).

It is also not uncommon for connectors to be flakey -- the "pins"
*in* the USB connector as well as the pigtail that invariably connects
the "front connectors" to the motherboard (the rear panel connectors
are more often than not directly soldered to the motherboard).

And, of course, iPod cables are also notoriously flakey
(not to mention the &*^!@#*&$% "charge only" cables!)

HTH

== 2 of 3 ==
Date: Sun, Dec 12 2010 12:06 pm
From: Baron

Terry Pinnell Inscribed thus:

> D Yuniskis <not.going.to.be@seen.com> wrote:
>
>>Hi Terry,
>>
>>Terry Pinnell wrote:
>>> I've dusted off a 4-port USB hub I had lying but can't find whatever
>>> adapter it came with. What are the standard specs for USB 2.0
>>> please? I want to replace a PC-powered hub with it.
>>>
>>> I have several old adapters at hand. One (which happily has the
>>> correct plug) has switchable outputs of 3V, 4.5V and 6V, with
>>> current capacity of 300 mA at 6V. options. Would the 4.5V be OK?
>>
>>5V at about 2+A -- for four *powered* ports; less if you
>>can guarantee the devices plugged into the hub have their
>>own power source(s). You won't be finding this in an
>>old-fashioned "transformer" wall wart (you'll need a small
>>switcher wall-wart)
>>
>>Most hubs that I have seen, lately, use a ~0.100 dia barrel
>>connector (center positive) -- though I have seen others.
>
> Thanks all, glad I asked, as I hadn't realised it needed such a heavy
> duty supply. At worse, I'll get out to the shed and make one.
>
> BTW, if you'll excuse a related question, is it usual for USB ports on
> the front of a PC case to be less reliable than ports on the back?
> Perhaps with lower current delivery? That's my motive for deploying
> this powered hub. An operation that failed from the front worked OK
> from the back (connecting an iPad to run an iTunes sync). That wasn't
> the only thing I changed, so it's not conclusive. But from subsequent
> googling I've seen several suggestions that this difference is a real
> one.

Open up the machine and unplug the ten pin cable header for the front
USB ports at the mainboard then plug it back in ! Could be the pins
are dirty. Its surprising what a little oxidisation can do !

Don't forget to take anti static precautions !!

--
Best Regards:
Baron.

== 3 of 3 ==
Date: Sun, Dec 12 2010 4:00 pm
From: whit3rd

On Dec 12, 7:33 am, Terry Pinnell <terrypi...@DELETEgmail.com> wrote:
> I've dusted off a 4-port USB hub I had lying but can't find whatever
> adapter it came with. What are the standard specs for USB 2.0

Well, it's 5V at 500 mA max on the USB pins; the
power adapter could be 5V, 5.1V, 6V, and anything (for
the max output power) from 2A to 2.5A (the hub could
need some internal power, but probably not much).

The various hubs use different input voltages because
the power-supply USB features are implemented in
several different ways.

==============================================================================
TOPIC: Removing smoking smell out of electronics?
http://groups.google.com/group/sci.electronics.repair/t/ca206ef62cb0cf13?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Dec 12 2010 12:03 pm
From: "DockScience"

"Keith" <keithdlee2000@gmail.com> wrote in message news:idmnp1$glo$1@news.eternal-september.org...
> All:
> I just a got great deal on a Samsung 32" HDTV. The only issue is the smoke smell. Is there a way I can
> get it off and out of my new HDTV without ruining the TV? Thank you.
>
> Keith Lee

The smell of stale tobacco smoke is one of the aromas that the human nose is most sensitive to... literally 1 part per billion.
A combination of partially oxidized heterocyclic nitrogen compounds with a tiny bit of sulfur malodors thrown in. Yum.

Chemically, it takes a pretty strong oxidizer to actually destroy the smell, so that's out for electronics.

Be advised that many plastics are VERY permeable to the odor molecules and the case may act as an odor reservoir for a long time if it has been exposed to smoke for long periods... even if their surfaces are clean. Glass is impermeable, so no worries there.

However, the thin layer of tar that condenses on surfaces around smokers is the main source of the odorants, so you have to get as much as that off as you can.

I would disassemble the case and clean the INTERIOR plastic surfaces with plastic friendly cleaners first, followed by clorox/water or clorox wipes (strong enough to react the odorants). Don't try to clean the circuit boards or cables. Too risky.

Rinse/wipe the case well with clean water afterwards, as you REALLY don't want those chlorine molecules anywhere near your copper circuit boards, even though they are "protected" with a conformal plastic film.

Unfortunately, the clorox wipes may discolor the plastic, so don't do it on the outside of the case. Cleaning the outside surfaces with a plastic friendly cleaner will physically remove the tars that hold and trap the odor there as well.

Strong UV can photochemically accellerate the oxidation in air, but UV strong enough to do that would also affect most plastics, particularly silicone rubber seals. So attacking them is not a great idea for long life.

The better approach is to either cook the smell out more rapidly by running (and exhausting) clean warm air through the enclosure or to capture the aroma molecules by trapping them on other larger molecules/substrates that don't evaporate... like activated charcoal (available in big bags in pet stores for fish tanks). Putting a small porous fabric bag full of ACTIVATED charcoal in or near the case would capture odor on the move. Bentonite or other expanded clays work too, just not as well.

You will be surprised how much odor charcoal can scavenge and hold.

You can try to cover up the smell too, for some reason, raspberry is more effective than most aromas in covering tobacco smoke. Vanilla works a bit too.

Either that or take up smoking or invite over smoking friends to stink up your place, so you can't smell the TV anymore.

Sorry for the Cliff Clavin approach here, but I actually worked on this odorant chemistry in a previous professional life.

== 2 of 2 ==
Date: Sun, Dec 12 2010 3:16 pm
From: Keith

DS:
Actually, the smell has dissipated. There is a slight plastic smell but only if you get close to the TV and
smell behind it. Even that seems to be dissipating. Thank goodness. Now, I have a year old TV for less
then half it's price then and more than 1/3 off it's new price today. :-)

Keith Lee

==============================================================================
TOPIC: OT: Lithium Cells Exploding
http://groups.google.com/group/sci.electronics.repair/t/181af8dd8c2e6fde?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, Dec 12 2010 12:10 pm
From: Allodoxaphobia

On Sun, 12 Dec 2010 00:52:03 +0000 (UTC), Cydrome Leader wrote:
>
> since when does nasa care about stuff catching on fire or exploding, or
> is there some sort of higher energy battery failure mode they prefer?

Since, I suppose, it costs giga-shekels per deca-stone to throw crap
into orbit, it seems obvious they would not want to imperil the results.

Then there was: http://history.nasa.gov/Apollo204/

== 2 of 2 ==
Date: Sun, Dec 12 2010 3:58 pm
From: Cydrome Leader

William Sommerwerck <grizzledgeezer@comcast.net> wrote:
>>> NASA won't allow any litium cells in space. We had to use 'Capstore'
>>> NVRAM in our products for space applications. Since the cost difference
>>> was small, we dropped the battery backed NVRAM from our products.
>
>> since when does nasa care about stuff catching on fire or exploding, or
>> is there some sort of higher energy battery failure mode they prefer?
>
> NASA has other considerations. For example, when astronauts used HP
> calculators, NASA required that the feet on the bottom be removed, to avoid
> possible outgassing from the rubber.

because the inside of the shuttle is a high vacuum chamber?

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