Bypassing an old laptop battery

[Blog the Haggis]

Hi All,

I'm trying to get a really old laptop (Mac Powerbook 170) running again but
its main battery seems to have died. I could open up the old battery pack
and replace the cells but I was wondering if there was a simpler solution.

Does anyone know whether attaching a capacitor between the terminals instead
of a battery and using the AC adapter for power would work...?

....or would I just send it the rest of the way into Silicon Heaven?

Cheers,

-Duncan
________________________________________

 

[Trevor Wilson]

Hi All,

I'm trying to get a really old laptop (Mac Powerbook 170) running again
but its main battery seems to have died. I could open up the old battery
pack and replace the cells but I was wondering if there was a simpler
solution.

Does anyone know whether attaching a capacitor between the terminals
instead of a battery and using the AC adapter for power would work...?

...or would I just send it the rest of the way into Silicon Heaven?

**Plug it into the mains. No need for extra capacitors.

 

[Blog the Haggis]

not without heavy duty AC electrolytic capacitors Trevor.

How old is really old?

If you can't replace the cells, or the whole battery with an equivalent,
(even externally), then Silicon Heaven may be the correct answer.

Don...

Old meaning one of the first Mac laptops ever built (1990-1991).

Unplugging the battery and running it directly from its AC adapter didn't do
anything, so I was wondering whether it needed the battery to complete the
power circuit.

To test this I thought connecting a capacitor (and perhaps a small resistor)
across the battery terminal would have similar characteristics to a flat
battery. Wouldn't the capacitor then come up to the correct voltage as the
laptop tries to charge it?

-Duncan

 

[Tim Polmear]

Hi All,

I'm trying to get a really old laptop (Mac Powerbook 170) running again but
its main battery seems to have died. I could open up the old battery pack
and replace the cells but I was wondering if there was a simpler solution.

Does anyone know whether attaching a capacitor between the terminals instead
of a battery and using the AC adapter for power would work...?

...or would I just send it the rest of the way into Silicon Heaven?

Cheers,

-Duncan
________________________________________

It may already be there. The CMOS battery may well have ruptured or
corroded a goodly portion of the motherboard. It happened to me. Not
with a Macbook but a laptop of similar antiquity.


____________________________________________________
"I like to be organised. A place for everything. And everything all over the place."

 

[Blog the Haggis]

It may already be there. The CMOS battery may well have ruptured or
corroded a goodly portion of the motherboard. It happened to me. Not
with a Macbook but a laptop of similar antiquity.

Visually the motherboard looks ok so I don't know if that's the problem....
The 3V CMOS battery is still putting out around 2.5V so I guess that is
within limits... (?)

-Duncan