[NTLK] MessagePad 2100 recell problem
gavin83209 at gmail.com
Fri Aug 6 00:35:32 EDT 2010
A while ago, I rebuilt a MessagePad 2100's spare battery pack with
regular store bought Rayovac cells. They are the type rated for 1000
cycles with no memory effect. I am having a number of problems with
it, the first of which is that they are too thick to fit inside the
Newton, forcing me to insert them without the top to make them thick.
The second problem is that the thermistor wasn't easily salvageable.
The third problem is that it only works 1% of the time.
The first day I rebuilt it, it would not work. About 11:30 that
night, it decided to turn itself on, though the Newton's battery gauge
behaved erratically, randomly changing the reading. Every one to five
minutes, it would shut down by itself until it stopped working at
about 11:45. I've spent a few days checking the battery connections
and everything looks okay after resoldering one wire that broke. I
read that it was the thermistor's positive end (it is the really
fragile one in the bottom right, rear case open and facing you). I've
tested power with a multimeter and found that it outputs comparable
power to the known working battery. After fixing the above wire, I
found that the known good battery's life increased from about 20
minutes to about a half an hour with no backlight. The other battery
still does not seem to work.
As far as construction goes, I had to make a few modifications. The
biggest one is that I had to replace the thermistor with a small
strand of copper wire in order to complete the circuit. Otherwise,
I've used electrical tape to reinforce pretty much everything except
the negative terminal in the battery.
As for the battery's behavior, when it is inserted, the Newton says
"Charging" with a full black bar for about two minutes before finally
saying "Charged" and displaying a full gray bar. When I unplug it, it
dies instantly and the Newton usually says that the battery died,
though sometimes says that all power was removed.
The battery electrically works, the Newton recognizes that it is
there, but it will not work for any length of time, except when it
randomly turns on. But my non-refurbished battery works fine. I'm
really stumped here. Does anybody have any other ideas? Thanks in
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