Re: [NTLK] After-market power adapter

From: dlandown_at_chroma.med.miami.edu
Date: Wed Jun 16 2004 - 05:46:45 PDT


Thanks. With this encourgement I borrowed a multimeter. It read 7.5V but
I couldn't get a current reading. The label on the adapter says
switching power supply, I thought that might be why I couldn't read any
current.

I'm running on the Newton on 4 AA batteries. I opened the SBM utility -
Battery indicator and then plugged in the adapter

                no adapter just plugged in 15 min later

Voltage 4.975 5.210 5.259
%Capacity 39 63 67
AC applied no yes yes
charge state discharging discharging discharging
charge current unknown 2.415 mA 2.415 mA

and no new smell from the Newton :)

Turning on the backlight didn't change the numbers. The charging current
bounces between 1.9, 2.4 and 2.8 mA which must be a lsb issue.

I wanted this adapter to run the Newton while plugged in, mostly to
support cards. I think it will work for that. This is not a complete
endorsement, I haven't tried to charge the rechargable batteries (I don't
have any).

David

On Wed, 16 Jun 2004, Johannes Wolf wrote:

> PLEASE CHECK BEFORE PLUGGING IT TO YOUR NEWT!!
>
> >From my own experience I can tell you that it is really bad when you realise
> a bed smell coming out of your Newt and the display switches off forever...
>
> It is a very easy thing to to - take a multimeter and measure the output
> voltage of your adapter.
> The most important thing is to check that the voltage in no load condition
> does not exceed 7.5 V!
> If this is the case the risk to damage your Newt is much lower but still not
> zero.
> The remaining risk is that the power adapter may provide too much current
> and/or a different impedance curve.
> If you have a look at the power adapter designers guide (available at Unna)
> you get a clear description on how the power adapters output voltage shall
> behave with respect to output current. The main thing is that there is a
> current limitation (may be even with fold back characteristics) that limit
> the current to a total maximum of 1.3 Amps.
> In case this maximum current is exceeded (this can hapen only during the
> fast charging of the Newton battery) you also risk to damage your Newt.
>
> The best way to find this out is to measure the voltage/current
> characteristics of the adapter.
>
> But a current measurement while applying a short to the output will do as
> well - the max. current shall be 1.3 Amps or below.
>
> Cheers
> Johannes
>
> > -----Original Message-----
> > From: newtontalk-bounce_at_newtontalk.net
> > [mailto:newtontalk-bounce_at_newtontalk.net]On Behalf Of
> > dlandown_at_chroma.med.miami.edu
> > Sent: Wednesday, June 16, 2004 2:14 AM
> > To: newtontalk_at_newtontalk.net
> > Subject: Re: [NTLK] After-market power adapter
>
>
>
> > Unfortunately I did not search the archives before going to ebay.
> > I just received a power adapter I "won" (5702385252). The add looks very
> > similar to the (5700198547) described below. The ad says
>
> > 9W AC Power Adapter   For Apple Newton Message Pad Brand New in white box.
>
> > Input Voltage:  100-120V
> > Output  voltage:  7.5V
>  
> > THESE UNITS WERE CUSTOM PRODUCED USING THE SAME SPECIFICATIONS AS THE
> > ORIGINAL APPLE NEWTON CHARGER.  THEY HAVE BEEN TESTED ON NUMEROUS 2000 AND
> > 2100 MODELS AND HAVE WORKED FLAWLESSLY. 
>
> > But the unit says
> > Model: SYS1089-1209L-W2
> ___
> > Output +9V --- 1.33A
> > Output Power 12W max
> > (It smells new and has a white box)
>
> > On query the seller says
>
> > "I forgot to attach a label explaining that the unit has incorrect
> > printing on it. The unit has correct specs."
>
> > Is it safe to plug it in to my precious Newton? Is there some other way
> > to test it? Has anyone had experience with this power adapter?
>
> > tia
>
> > David
>
> --
> This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
> Official Newton FAQ: http://www.chuma.org/newton/faq/
> WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/
>
>

-- 
This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
Official Newton FAQ: http://www.chuma.org/newton/faq/
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