Manuel Mejia Jr
- 2000.05.09
A few weeks ago, I overcame what apparently is the most common
problem with aging PowerBook 100s - the short charge and life span
of the PB 100's lead acid battery. I had my father, a retired
carpenter, create a wooden adapter that goes into the battery
compartment. The adapter allows me to use common 7.2 volt R/C car
battery packs to run the computer. To learn more about how to build
such an adapter, refer to the plan that
accompanies this article.
In recent weeks, I have field tested the adapter. I find that
the PB 100 will run with its backlight on with no other attachments
(like the floppy drive) plugged in for about 70 minutes before
shutting down. Unlike the old lead acid battery pack, you will not
have much time between the initial warning that you are low on
power and shut down. The NiCad 7.2 cell pack delivers a constant
level of voltage to the PB 100 for those 60-70 minutes before
heating up a few degrees and then losing its charge. Once the
initial warning comes up, you have about 25 seconds to save
your work and quit your application.
The standard battery monitor that is part of System 7.0.1 does
not give the user adequate warning about the approaching loss of
power. The desk accessory just tells you that you have full power
until just before the battery pack is exhausted. Since such short
notice is of limited use, I deleted the battery desk accessory from
the hard drive and rely on my watch and the first stage warning of
imminent power loss from the PB 100.
Since the publication of the initial
Carpenter's article, I have gotten email asking why I did not
choose to wire a new set of batteries into the battery compartment
of the PB 100. I have reviewed various comments about rebuilding
existing PB 100 battery packs so that they will function again. I
felt that this solution required too much effort for a pack that is
likely to wear out not long after it has been rebuilt.
I also have no desire to open up my PB 100's outer casing so
that I could access the battery compartment. The device is very
delicate once opened up, and I did not want to risk damaging the
machine.
For those who need more than 60-70 minutes of run time on the PB
100 using a wood adapter, all you need to do is wire additional 7.2
volt battery packs in parallel to one Tamya plug. Each pack that is
added will add another hour of operating time following the
conditions I stated previously. Another option that one can use is
to carry spare 7.2 volt battery packs with you and swap out power
sources as they are used up.
For those PB 100 users wanting to use the AC plug connector
rather than the wood block, this should work providing that you can
find a spare plug. Those plugs may be a bit hard to come by. I had
only 2 and both are attached to working power supplies. In the
final analysis, the wood plug was the easiest way for me to make my
PB 100 mobile again and free it from is fate as a desktop
computer - forever dependent on a wall outlet for power.
Manuel Mejia Jr is familiar with Mac IIs, LCs, and older PowerBooks. He
uses his Mac LC, PowerBook 145B, and PB 100 with System 7.1 on a
regular basis and recently added a Mac Plus running System 6 to his
collection. He's quite familiar with both System 6 and System 7. He
also owns the Pina books on repairing compact Macs from 128k through
the SE. You can read more about Manuel's computers in Manuel Mejia Jr's Four Old Macs.
