- ... For the 128K and 512k MAC s - It s just a AA battery on the outside of the chassis. I have both types of MAC. It could have just been a coincidence, butMessage 1 of 8 , Oct 2, 2007View SourceAt 11:03 AM 10/2/2007 +0000, you wrote:
>The battery provides power for the real-time clock and CMOS settingsFor the 128K and 512k MAC's - It's just a AA battery on the outside of the
>circuitry. I don't believe the original, recommended battery is
>available anymore, but one can be made up from a few double A's.
>I contributed an old working MAC which included a hard drive and
>floppys. It's probably still in the basement.
chassis. I have both types of MAC. It could have just been a coincidence,
but replacing the battery allowed me to get the disk to eject for the first
time. The AA battery is installed like any toy with batteries...there's a
little plastic flap/cover you pop off on the outside of the case. I am
sure that there is a web resource that explains the battery, I did not look
very hard. I will be demoing the Mac in class later in the semester and I
will by then do more research.
- ... I don t know what museum piece means specifically, but I appreciate the general sense that it s an early Mac 128K and so has some value in history. ButMessage 2 of 8 , Oct 2, 2007View Source"John Allain" <allain@...> wrote:
>I don't know what "museum piece" means specifically, but I appreciate
> Sounds like the Mac "model 1". If so then it's quite a
> museum piece.
the general sense that it's an early Mac 128K and so has some value in
history. But there were many of them made, so they are not rare.
Cosmetic condition determines the value of them, as they easily fade
in roomlight or sunlight; working condition is of importance. The unit
we have is slightly faded, probably worth "about" $200, could be
bought for less. I would not be comfortable about an extended
discussion of "value" beyond that.
> If there's any interest in a slightlyThat's up to Evan, but MARCH has a few Mac Classics which would likely
> later model for heavy display use I could pony up one
> of those but have no model 1. Thanks for the donation.
be adequate for use. I'm told there may be other "compact" Macs in the
accumulation. Regarding "the donation", the Macs I worked on
were already in MARCH's possession. I added some parts and time and
knowledge, so I'll take some thanks for doing some work.
> > if a member has a 400K floppy drive whichThe 400K Apple drive was only used in 128K and 512K Macs. The 512KE
> > is not working and wishes to donate it,
> How long did the 400K drive last? Maybe one of my later
> models has one for yours.
> John A.
Mac used a 800K drive and updates to the ROMS and a controller chip
called the IWM chip was also updated. There was an external 400K
floppy drive, also.
Thanks for the comments!
Herbert R. Johnson, New Jersey USA
http://www.retrotechnology.com/herbs_stuff/ web site
http://www.retrotechnology.net/herbs_stuff/ domain mirror
my email address: hjohnson AAT retrotechnology DOTT com
if no reply, try in a few days: herbjohnson ATT comcast DOTT net
"Herb's Stuff": old Mac, SGI, 8-inch floppy drives
S-100 IMSAI Altair computers, docs, by "Dr. S-100"
- ... The PRAM memory requires a battery to retain its contents. Some non essential settings are there. In addition, the battery runs the time of day clock.Message 3 of 8 , Oct 2, 2007View Source"B Degnan" <billdeg@...> wrote:
>The "PRAM" memory requires a battery to retain its contents. Some non
> What is the battery for?
essential settings are there. In addition, the battery runs the time
of day clock. Running a small circuit all the time for years, on
exposed copper circuits, in a humid environment, turns the copper to
copper oxide - like your car battery's terminals. The battery will
die, then crack open, and spill goop and spoil circuits. The battery
contacts will corrode and fall off.
In other words, batteries are evil.
usual Web page links, etc.