Fair enough ....
That would still leave about 8 volts after double-phase
rectification to charge the nicads with. (thru a 4.7ohm
internal resistor)
Never operate the TI59 without the nicads! when
the machine is turned on the excess voltage
will be dumpt into them so the -vbat will be kept at
-3.7 Volts! To operate it without nicads might
toast the machine !!!!
Sipke de Wal
-------------------------------------------------
http://xgistor.ath.cx
-------------------------------------------------
----- Original Message -----
From: "Carlos Murillo" <carlos_murillo_at_epm.net.co>
To: <cctalk_at_classiccmp.org>
Sent: Tuesday, August 13, 2002 6:35 AM
Subject: Re: TI-59 question
> At 06:54 PM 8/12/02 +0100, you wrote:
> >Failing that, if you can find the right connector (possibly from another
> >TI calc PSU) the TI-59 requires 6.2V 200mA AC.
> >
> >I always wanted a TI-59, but I have to make do with a -58...
>
> You can probably build something with epoxy/rubber and a couple
> of pins off a female DB-25 connector..
>
> A word of caution: if you are going to build a charger with a 6.3V
> transformer, keep in mind that the chargers that TI provided
> for this and other calculators had very high secondary winding
> resistances; I just measured mine, and it is 16 ohms. I have
> no idea about the reactance, though.
>
> The high resistance in effect limits the maximum current across
> the rectifier diodes and battery. I suspect that if you connect
> a < 3ohm transformer something might burn.
>
> carlos.
>
>
> --------------------------------------------------------------
> Carlos E. Murillo-Sanchez carlos_murillo_at_nospammers.ieee.org
>
Received on Tue Aug 13 2002 - 11:20:01 BST