From: Frank Gruendel (fg2_at_pda-soft.de)
Date: Sun Dec 21 2003 - 16:56:20 PST
> I've finally gotten
> a 7.5v power supply. It supplies 750mA, which is apparently not enough
> to get the eMate to boot-the "lightbulb" screen appears and then
> disappears in just a wink.
750 mA is more than sufficient to boot a healthy eMate. It is more than
the original AC adapter of the older Newtons can supply, and you can
boot
an eMate with those without any problem.
If it disappears immediately after starting powerup, I'd think there's a
problem with the power supply. Maybe the voltage drops too much when
the Newton starts to boot. How exactly is the AC adapter labeled? Are
you sure it can put the 750 mA out while maintaining 7.5 Volt, or at
some lower voltage?
> The "charging" light appears green, then
> amber after a few seconds when I plug it in to the eMate. I'm using a
> pack that I know is good--it's some new 2000mAH NiMHs I put together
> just like the alkalines, except that I installed the thermistor, too,
> this time. My problem is that the battery won't charge.
You need to measure the thermistor's resistance at the plug that plugs
into the eMate mainboard, not anywhere else. If you can't measure it
there, the eMate won't see it and hence think it's running off
alkalines.
The resistor is connected to the two white wires.
My batteries aren't well-charged, and my pack only shows about 3V
between
the leads.
This is a beginning deep-discharge. Normally the eMate should power off
at about 3.7 Volt or so.
> The thermistor is working (reads ~7KOhm, down to about 5 when I
> hold it in my fingers) fine, and the emate boots (partially) with only
> the wall adaptor, so everything SHOULD be OK to charge, but when I
plug the
> eMate into the wall, I never get a charging voltage across the
battery, and
> the battery doesn't charge.
You might want to download NewtTest (available in the software section
of the
site in the signature) and, provided you can get the eMate to power up
for long
enough, install it. It has a "Battery" subtest that will tell you a lot
about
what is going on charge-wise.
> I read somewhere that a 10KOhm resistor will let
> the eMate charge a battery but without the thermistor safety, so I
tried
> that instead of the thermistor, just in case, but still no charging.
It will, provided the 10 kOhm can be measured at the power plug (see
above).
But I'd strongly recommend not to do it that way. You can be dead sure
you'd overcharge the batteries, and if you don't take care, you'd do it
in a way that they'd react very unfriendly to. If you have ever seen a
small capacitor explode, you'll rather not take chances with a battery
that is
waaaayyyy bigger...
Can anyone shed any light upon how to get the eMate to charge my pack?
If I were you, I'd try to get access to an original Newton adapter
(every model's adapter will be ok) for a minute and try it with this
one. If the battery still won't charge, check if the eMate sees the
thermistor as described above. If you still can't get it to charge,
either the battery or the eMate or both have a hardware problem.
If you want to risk shipping cost from Germany and back, I can send you
a battery and an AC adapter that definitely work, and you can try to
figure out what's wrong. Or you could send me the eMate along with
the battery and adapter and I could have a look. Looking, as usual,
is free for list members. If I find what's wrong and we can't work
anything out (which as yet hasn't happened), all you'll loose is the
shipping cost, and you'd at least know what the problem is.
Good luck
Frank
-- Newton Software and Hardware at http://www.pda-soft.de
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