On Sat, 07 Jan 2017 16:48:38 +0000, T i m wrote:

Hi all and HNY.

Daughter recently bought a 'refurbished' Samsumg Galaxy Tab2 10.1"
(tablet) and it seemed ok at first. However, the supplier forgot to
include the charger. She called them and in spite of requesting a
genuine Samsung one, they sent her a generic jobby (and only 650mA).

Along the way (and not helped by the charger thing) she's allowed it to
go flat and now it won't charge up again (I've tried various chargers,
inc a 2A Samsung one) and after Googling about it looks like this (sort
of thing) is a known problem with these Lithium batteries and Samsung
tablets (and probably other makes and devices as well etc).

One solution seems to be to pop the back off, pull the battery
connector, refit the battery and away it (often) goes but it is also
suggested that if you get to that low voltage state again, it will /
could lock up again. ;-(

However, one chap on Youtube suggests a more permanent 'fix' by the
addition of a small 'bypass' diode and whilst I'm happy to do that (I
was a field support guy, years ago and still try to keep my hand in with
basic repairs), I thought I'd ask here if it sounds 'sensible'?

https://www.youtube.com/watch?v=2ggQU3E01IQ

I'm not able to work out where on the diagram he put the diode or if it
has any other (negative?) impact. He starts to show the schematics from
4:20 onwards and there are also links to them and the full service
manual in the text. Ours is a GT-P5100, as are the manuals he links to
but he seems to be discussing the GT-P3100 (the 7" model and may not
have the same PCB layout for someone old / simple like me to follow
g)?

Obviously our first port of call will be the supplier but we didn't want
to go though the trouble of sending it back, for them to disconnect the
battery and send it back to us, only for it to lock up again later.? ;-(

Basically she was just looking for a 3g 10" tablet that was 'nice' to
use and that she could afford and the s/u 10" Tab2 seemed to fit the
bill.

Thanks for your time in any case. ;-)

Cheers, T i m

Charge initially at a very low rate until the protection circuitry sees a
voltage higher than 3V from each cell in the battery, then charge
normally.
If it doesn't take a charge then it's dead.