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Re: Why is the micro USB so fragile compared to mini USB cable ends?
cl wrote, on Thu, 21 Aug 2014 09:19:06 +0100:

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I put a dab of the wife's pink nail polish on the USB top of the  
connectors, and, in the case of the less obvious device ports, on the  
device itself, where the pink dots are to be visually matched *before*  
one plugs in the connector.

So, at least in "my" situation, that's not why the USB nibs are failing.
I think it's a bad batch of cables from Frys.

I found an unopened original cable still in its packaging from Frys
(I had bought about a dozen cables at the same time):
      
http://tinypic.com/view.php?pic12%4v8ns&s=8

Those cables stink!

Roxgo, http://www.roxgo.com ,  
Manufactured and exported by Zendex, Inc, South El Monte, CA 91733,  
Made in China, UPC 851556004031

Re: Why is the micro USB so fragile compared to mini USB cable ends?
On Thu, 21 Aug 2014 10:43:54 +0000 (UTC), Avraham Bernholz

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Or, just buy a cable with a connector that fits both ways:
<http://flipperusb.com
Too bad it's only available for the large USB connector.

Or, just wait for the new Type C USB connector, which is reversible:
<http://www.forbes.com/sites/gordonkelly/2014/08/18/usb-type-c-guide/

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Find a microscope and look at the gold plating on the connector.  If
it's nice and shiny gold, you win.  If it looks dark and dingy, like
some of the base metal is showing through the plating, it's much too
thinly plated.

Strictly speaking, the USB connector system is a bad joke.  Ask any
connector or switch manufacturer about switching DC with a gold plated
connector and they'll cringe.  Gold plating is suppose to be for "dry"
loads (i.e. no DC).  If one must run DC through a gold connector, the
power is suppose to be disconnected and all caps are suppose to be
discharged.  For "live" loads, one is suppose to use silver.  However,
the USB connector has both a dry data load, and a live DC power load.
Therefore, we see all the inrush current protection on the DC pins.
<https://www.nkkswitches.com/pdf/switchcontactmaterial.pdf

Before you declare your cables to be junk, you might want to run some
bench tests with your five(?) assorted power supplies under various
load conditions.  Also check what they do for inrush current.  My
guess is that at least one of them will be problematic and possibly
the culprit.

The thin USB cables may actually be an improvement.  The higher
resistance wire might reduce the inrush current a little.  For short
circuit protection, they'll probably make a tolerable fuse.  I'm too
lazy to do the calcs and measure the wire gauge.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Why is the micro USB so fragile compared to mini USB cable ends?
On 08/21/2014 03:43 AM, Avraham Bernholz wrote:
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FWIW, I've never had any problems with cables -- or anything else --  
from DealExtreme.
http://www.dx.com/s/USB%2bcables?category31%2

There have been problems with some items right out of the box -- PS2 to  
USB keyboard connectors, and a never-could-have-worked  
mp3-player-to-cassettte adapter.  I emailed them and sent photos of the  
items in question, and they credited me immediately.

The disadvantage, of course, is the 2-3 week shipping time.  Big deal  
:-)  They now sell some stuff out of their warehouse in California with  
much faster delivery, but if they're doing it legally they'll charge  
sales tax on that stuff, and I believe in avoiding sales tax whenever  
possible.

--  
Cheers, Bev
++++++++++++++++++++++++++++++++++++++++++++++


Re: Why is the micro USB so fragile compared to mini USB cable ends?

Avraham Bernholz wrote:
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   Replace the connectors, they are cheap enough.


http://www.ebay.com/itm/121338466227
--  
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

Re: Why is the micro USB so fragile compared to mini USB cable ends?
Michael A. Terrell wrote, on Wed, 20 Aug 2014 14:02:13 -0400:

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I didn't know you *could* (easily) replace the connectors!
And, at 5 cents each, no less.  

How can they possibly make money selling those micro usb connectors
for 5 cents each, with shipping from Szechuan China being 80 cents?

BTW, are they crimp on? Glue on? Solder on? What?
http://www.ebay.com/itm/121338466227

Re: Why is the micro USB so fragile compared to mini USB cable ends?
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You sure about that 80c ?  I've got lots of stuff for $1 total cost.

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Those are definitely solder, you can see that in the second and third last  
photos.  


Re: Why is the micro USB so fragile compared to mini USB cableends?

Avraham Bernholz wrote:
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   10/.99 = $.099 each, not $.05. Shipping was 79 cents, for a total of
$1.78.  The 10 I bought just arrived.



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   Solder, like Rod stated.


--  
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

Re: Why is the micro USB so fragile compared to mini USB cable ends?
Michael A. Terrell wrote, on Wed, 20 Aug 2014 14:02:13 -0400:

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I also have to replace the Duracell USB wall charger I bought  
from Frys, as it just fell apart in my hands today!

http://tinypic.com/view.php?pic=2vjpnv8&s=8

That could have been dangerous because it left that missing pin  
in hot port of the wall socket!

Re: Why is the micro USB so fragile compared to mini USB cable ends?


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Have a look at the charger teardowns on youtube

You may never buy a non branded mains charger from china again.  


Re: Why is the micro USB so fragile compared to mini USB cable ends?
On 08/20/2014 12:56 PM, Avraham Bernholz wrote:
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I'm getting bummed out on Duracell chargers and rechargeables.  Several  
years ago (maybe 2008) I bought a set of the precharged Duracells --  
supposed to maintain a charge while sitting on a shelf for nearly a year  
-- and the spares (charged at the same time as the ones in my camera)  
are dead when the ones I've been using in my camera die.  The Duracell  
charger (the BIG one!) stopped working within 2 years.  I now carry more  
Kirkland AAs with me Just In Case.

Are the Eneloops any better?


--  
Cheers, Bev
==========================================================
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Re: Why is the micro USB so fragile compared to mini USB cable ends?
On Thu, 21 Aug 2014 15:56:39 -0700, The Real Bev

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Yes.  I use them in my various cameras.  Hardly any self-discharge
after many months.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Why is the micro USB so fragile compared to mini USB cable ends?
On Wed, 20 Aug 2014 04:38:17 +0000 (UTC), Avraham Bernholz

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Because the micro-USB is designed to be fragile.  The spec for both
connectors was originally 1,500 insertion cycles.  That's roughly once
per day for 5 years, which is more than the average life of the cell
phone or gadget which uses the connector.  A longer life would just be
a waste of money (for the manufacturers).  The micro-USB spec was
later increased to 5,000 or even 10,000 cycles, which I suspect was
more wishful thinking than actual testing.

I've torn apart a few "failed" mini and micro USB connectors, mostly
on cell phones.  Although most of the permanent damage is from
breakage, a fair number of the gold contacts had the plating blown
off, apparently from arcing.  My guess(tm) is that inserting the
connector with the power applied is discharging a large capacitor in
the power source, through the connector, to the cell phone.  It
doesn't take many arcs to destroy the gold plating.  The USB 2.0
specification limits the initial inrush current to 0.1A before the
chips negotiate to turn on the current to anywhere from 0.5A to 2A
maximum current.  The spec also limits the size of the load
capacitance to 10uf.  The idea is to prevent arcing.  However, if the
power supply vendor ignores the spec, the connector contacts will fry
in short order.

Some relevant comments on USB:
<http://electronics.stackexchange.com/questions/18552/why-was-mini-usb-deprecated-in-favor-of-micro-usb
<http://electronics.stackexchange.com/questions/36375/understanding-usb-inrush-current-requirements
<http://en.wikipedia.org/wiki/USB#Durability

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Why is the micro USB so fragile compared to mini USB cable ends?

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That is why I asked why the origional poster was plugging in about 3 to 10  
times a day.  



Re: Why is the micro USB so fragile compared to mini USB cable ends?
Dne 20.8.2014 v 23:57 Jeff Liebermann napsal(a):
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I instinctively plug micro USB end into a phone,
before I plug the USB end into USB socket of PC or a charge.

--  
Poutnik

Wise man guards the words he says,
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Re: Why is the micro USB so fragile compared to mini USB cable ends?
Poutnik wrote, on Thu, 21 Aug 2014 07:18:51 +0200:

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One thing I've just learned, from Jeff Liebermann, is to do  
the same!

Re: Why is the micro USB so fragile compared to mini USB cable ends?
wrote:

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That's probably un-necessary if you have a quality charger and
properly designed cell phone.  0.1A inrush current is not going to do
any damage to the gold plating.  However, if you have a no-name
charger, or worse are charging from a "stiff" 5v source, it's worth
checking what the charger does.  I have a USB extension cable where I
cut the heavy 5V positive wire.  I put various ammeters in series to
measure current drain.  Today, you can get such devices on eBay for
very little:
<http://www.ebay.com/itm/171427886388
However, these will not show the required 0.1A inrush current limit or
any current spike caused by an oversized capacitive load.  For those,
I insert a 0.1 ohm resistor (actually a length of nichrome wire).
Using a dual trace oscilloscope, I put the Ch A probe on one side of
the resistor, and the Ch B probe on the other, and the scope in
differential (A-B) mode.  That's necessary because grounding the +5V
power line with the scope probe ground is not a good idea.  I can post
a photo of what it should look like if anyone needs a sanity check.

Note that USB 3.0 is different.  Current is now up to 900 ma and
overload protection is required:
<http://www.mouser.com/applications/usb30_circuit_protection/>

Simulation of USB 2 inrush current:
<http://www.epsilonlabs.com/USB_Inrush_I.html

The design of the micro-USB connector system intentionally moved all
the failure prone parts to the plug.  There's not much you can do to
improve or protect the receptacle on the phone end, but plenty you can
do on the cable and charger end.  

There is an amazing amount of junk USB power supplies out there:
<http://www.lygte-info.dk/info/usbPowerSupplyTest%20UK.html
The real Apple charger:
<http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html
and the not so real clone:
<http://www.righto.com/2012/03/inside-cheap-phone-charger-and-why-you.html

I bought a few cheap USB car chargers on eBay, and stupidly passed
them out to friends as presents.  After I looked inside, I had to run
around and confiscate them before they blew up someones phone.
<
http://802.11junk.com/jeffl/LTspice/Cig%20Lighter%20USB%20charger/Circuit%20view.jpg

Notice that there is a short across the data wires (used to fool the
phone into believing that the maximum current available).  The front
has two USB jacks, labeled 2A and 0.5A.  With the short, they're both
identical.  I tried to build an LTspice model of the device, but
failed because couldn't identify the chip used.

I later bought some of these which are fairly cheap, and won't kill
your phone:
<
http://802.11junk.com/jeffl/Powergen%20USB%20car%20charger/Powergen%20USB%20car%20charger.jpg




--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
We've slightly trimmed the long signature. Click to see the full one.
Re: Why is the micro USB so fragile compared to mini USB cable ends?


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Where are you getting those from ?  


Re: Why is the micro USB so fragile compared to mini USB cable ends?
On Fri, 22 Aug 2014 06:18:57 +1000, "Rod Speed"

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Amazon and eBay.  Available in white and Darth Vader black:
<(Amazon.com product link shortened)>
<http://www.ebay.com/itm/131257596903
<http://tips.navas.us/2014/01/best-usb-car-charger.html
<https://www.google.com/search?tbm=isch&q=powergen+usb+car+charger

Grumble... I paid $15 and now the price is $10.  Oh well.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
We've slightly trimmed the long signature. Click to see the full one.
Re: Why is the micro USB so fragile compared to mini USB cable ends?
wrote:

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Same here.

It's my general rule: Plug in the most fragile first, the least
fragile last.

This is what I tell my girlfriend ...

Start charging:

1. Plug micro USB into phone/tablet
2. Plug USB A into charger
3. Plug charger into mains

or

1. Plug micro USB into phone
2. Plug USB A into laptop


And after charging:

1. Unplug charger from mains
2. Unplug USB A from charger
3. Unplug micro USB from phone/tablet

or

1. Unplug USB A from laptop
2. Unplug micro USB from phone/tablet


Never had a USB cable fail on me.
--  
Kees Nuyt

Re: Why is the micro USB so fragile compared to mini USB cable ends?


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Way too much hassle. Just leave the cable and charger plugged in all
the time. The micro end still receives the same number of inserts.

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Me neither.

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