Update: Charging MP3 Player, Coby MP620-4G

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Hi,
      Since my original post, I bought the Coby MP620-4G MP3 player.
The OM says to use a "high power" USB port (computer).  There is
no other information in the OM or at their web site on a recommended
charging current if using a different source.

      I can set the maximum current limit on my lab quality regulated
power supply.  Note: There is no connection to the USB  "data" pins
with this setup.  The MP3 player display indicates that it was "charging".

     When I first charged this MP3 player at 200 MA max, which didn't take
very long before the display said the battery is "charged",   I loaded it with
several hundred songs (MP3). It played for a little over an hour then the
player "died" (no warning).

     I recharged it at 100 MA max and it played over 5 hours, but I didn't run
it until it "died".  Again, when I charged it at 200 MA max, which didn't take
long,  it played for 1hr and 10 minutes, then "died".

    For the second time, I charged it at 100 MA max, and it plays a long time.

                           John

PS,  Remove "ine" from my email address

    

Re: Update: Charging MP3 Player, Coby MP620-4G


Hi!

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...or self powered hub (one with a power adapter that plugs into it.

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This tells me that the owner's manual is wrong, at least in part.
100mA is the maximum amount of current a USB host is supposed to
provide without the attached device requesting more, up to 500mA. Some
do, some don't. Without any data pins in the connector, I do not think
there is a way for this player to tell the host what it wants in terms
of current delivery. (The lack of data pin wiring is surprising. How
are you expected to put songs on the player?)

The behavior of the player also suggests that its charging circuit
becomes confused when additional current is provided to it, and as a
result, it reports the battery being fully charged before it is.
Perhaps if it were allowed to remain plugged in even after reporting a
"full" charge, it would finish charging the battery by way of a slow
charge.

William

Re: Update: Charging MP3 Player, Coby MP620-4G



snipped-for-privacy@verizon.net wrote:
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  A USB port is supposed to provide 500 mA max.



--
Greed is the root of all eBay.

Re: Update: Charging MP3 Player, Coby MP620-4G


On Wed, 10 Mar 2010 18:27:13 -0500 "Michael A. Terrell"

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According to the specification, yes. However, I've seen motherboards that
connect +5V directly to the USB port.

Re: Update: Charging MP3 Player, Coby MP620-4G



JW wrote:
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with
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run
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take
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time.
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   IBM did that with the keyboard on their original XT motherboard, with
no fuse.  I had a customer's keyboard cable short at the keyboard.  If
he hadn't been at the computer when it happened, it would have set his
house on fire.  There was nothing but a few pieces of bare, burnt wire
left.

   Do those motherboards have self resetting fuses?  If not, there is no
way I would use them or let anyone else get their hands on them.


--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'

Re: Update: Charging MP3 Player, Coby MP620-4G


On Thu, 11 Mar 2010 13:10:55 -0500 "Michael A. Terrell"

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with
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run
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take
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time.
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Keyboard cables with 24/26ga wire make nice resistors. :)
I'm surprised that IBM would have missed something like that.

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I'm not sure if they did or not. I'd take a look now, but I can't remember
which one of the dozens we have around here was the one wired in that
way... All I know is that the resistance between +5 and the USB socket was
less than an ohm. Usually there's a switched FET and it will read open.

Re: Update: Charging MP3 Player, Coby MP620-4G



JW wrote:
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   Even worse, the power supply connector was next to the keyboard
connect with a very heavy trace between them. It destroyed the keyboard,
but didn't damage the computer.


   A former IBM EE involved in the first IBM PC design told me that the
board layout and production was outsourced, just like the original 63
Watt Astec power supply used before hard drives were supported by DOS
2.xx.  He had one of the prototype IBM PC series that had a 128 KB, five
slot motherboard with ROM basic and a cassette port. I repaired it for
him when the original floppy drive controller died.  He was thrilled
that I had the same board on hand.  I modified his motherboard to the
640 KB version to free up two of the five slots.  the old man was
thrilled to have it working again, after at least one computer store
told him to throw it in their dumpster.

 
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  A self resetting fuse would fall into that range.


  


--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'

Re: Update: Charging MP3 Player, Coby MP620-4G
Hi,

    This "problem" with the MP3 player may have been a "fluke".  I went
into "system tools" and activated a "reset".  When I tried to play music,
it presented a "refresh" option, which I did.  I found technical information
on the web about charging an IPOD/MP3 player.  This time I set the current
limit to 600MA.   I charged the MP3 player, and now everything seems fine.

                          John

PS,  Remove "ine" from my email address

    

Re: Charging Portable MP3 Player (Not IPod)
Hi,

    This "problem" with the MP3 player may have been a "fluke".  I went
into "system tools" and activated a "reset".  When I tried to play music,
it presented a "refresh" option, which I did.  I found technical information
on the web about charging an IPOD/MP3 player.  This time I set the current
limit to 600MA.   I charged the MP3 player, and now everything seems fine.

                          John

PS,  Remove "ine" from my email address



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