Hello!
As I told you in a previous message, I have done an experiment on my Duo
230 PRAM battery. It was completely dead (I did lots of checkings with a
variable power supply, trying to resuscitate it to not avail). So I asked
to the battery seller. He smiled and told me 'You will never find this in
Spain!'. Sad.
He told me the NON rechargeable Li batteries used in PC mainboards were
exactly same size and voltage... So I decided to give them a try. But,
logically, you just can't replace a rechargeable with a non rechargeable
battery as-is. And, to make things worse, PRAM battery in the 230 has a
intermediate output:
batteries: |+ -| |+ -|
wires: red white black
I guess charging is done by red and black wires and the middle point is
used to power low voltage memory... I guess...
So what I have done is to add a diode in the red wire (anode to the battery
and cathode to the wire):
battery + -----|>|----- red wire
That way the battery will not get any current from the charging system but
will be able to power the PRAM, with an small voltage decrease (the diode
voltage drop)
So far it works... how much it will last?. No clue!. Would it really
prevent damage to the battery or computer?. Hope so!
I am really interested in hearing from you about similar experiences... I
am sure somebody else has done this already.
Best regards,
JOSE
PS: thinking a bit more on this, adding another diode to the intermediate
(3V) point seems to be a good idea... I will probably do it. In this case,
a Germanium diode would be better due to the lower voltage drop. We have
just 3V to play with; if the circuit powered by that voltage is critical,
voltage wise, a Si diode voltage drop could be too much.
----------------------------------------------------------------------
73 EB5AGV / EC5AAU - JOSE V. GAVILA
La Canyada - Valencia (SPAIN)
Vintage Radio: http://jvgavila.com
Vintage Test Equipment: http://jvgavila.com/testeq.htm
European Boatanchors List: http://groups.yahoo.com/group/euro_ba_swap
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