Re: [NTLK] weird battery issues 2100

From: Marco Mailand (
Date: Fri Mar 08 2002 - 03:57:55 EST

> The unit is off. I take out the battery and replace it with a fully
> charged battery (both apple nimh packs). I turn unit on. It restarts,
> meaning reactivates all packages and wipes its immediate memory (some
> prefs are gone)
Some prefs are gone is really weird and should not happen.

> Is that normal? Why cant I swap batteries when the unit is off w/o
> forcing this restart cycle?
This is completely normal. I normally don't swap batteries w/o connecting
the AC adaptor (to save the 'hassle' of restart)

> No backup batt, ok, but isnt there some thing in there?
There's the super cap and I did recently some measurements. I connected a
digital multimeter and measured its voltage:
1. It's nominally 3.3V, so some of the innards work with that at least as
sleep or backup voltage.
2. The voltage dropped very slowly, by about 30mV per minute, but keep in
mind that the multimeter loads with about 10MOhm.
3. If one presses reset and power at the same time the drop rate doubles
which confirmes that this procedure is helpful to wake-up a MP2k which can't
be switched on.
4. My Newton did not loose prefs up until a voltage of 1.5V. Lower voltages
I didn't try.
5. Upon connecting an AC adapter the backup super cap voltage increases
immediately to 3.3V, there seems to be no delay or slow recharging.

It would be nice to confirm at which super cap voltages the Newton forgets
all settings or goes to the 'I don't like to wake-up state' but therefore we
would need a sort of controlled fast voltage setting, which I couldn't
realize quickly. Maybe one day...

> One time, when I swapped the batteries while the unit was off, and
> then pulled the start button, the unit flashed the message "do you
> want to erase everything
This is again as it is supposed to be if the NOS 'thinks' that a brain wipe
is necessary. You did probably hold down the power switch for more than 10s.

With best Regards / Viele Gruesse!

Marco Mailand

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