I collect home micros, and I recently acquired a Mac
128K. However, it's
been quite heavily modified with contemporary third-party add-ons. It's
been taken up to 1M RAM and it's had a SCSI interface installed.
Cool!
The memory has been taken up to 512K by removing the
64K x 1 bit RAM chips
and replacing them with 256K x 1 bit chips, plus adding a few discrete
components (not hard, considering the 128K and 512K Macs shared the same PC
board). It has then been taken up to 1M by adding a third-party 512K RAM
expansion board, which plugs into one of the RAM sockets (the chip it
displaces being installed onto the expansion board), and is connected to
the address decoding by several flying leads.
A most interesting upgrade, I have
several of those liittle add-on boards
to allow that upgrade. Not sure what to do with them, though. Just waiting
for a bunch of 128K's to come my way, I guess...
The SCSI interface has been installed by removing the
ROM chips, plugging a
daughterboard into the empty ROM sockets, and plugging the ROM chips into
the daughterboard. The SCSI socket replaces the cover over the battery in
the back of the Mac.
Also very interesting. I've never quite figured them out.
So, my question is, should I:
1) Leave it as it is;
Definitley, unless(or until) it stops working, and then you
have the fun
job of figuring out which one is bad...
2) Remove the SCSI interface (easy, just remove the
daughter board, take the
ROM chips out of it and put them back into the motherboard's ROM sockets);
The SCSI is far too useful to remove unless broken...
3) Remove the SCSI interface *and* the 512K RAM
daughter board (not *too*
hard,
desolder the flying leads (taking note of where they go to, just in case I
want to reinstall the board), remove the board from the RAM chip's socket,
remove the RAM chip from the daughterboard and put it back in the
motherboard's now-empty RAM socket);
Same as before for the SCSI part, and
that extra RAM is very useful unless
you have some VERY old Mac software sitting around(getting a 512K running
isn't too hard, but the 128K in stock config is ALMOST useless)
4) Take it back to original condition (quite difficult,
as well as
steps 1)and 2) it involves desoldering 16 256K x 1 bit RAM chips, (plus
a few discrete components) and soldering in 16 64K x 1 bit RAM chips).
Too hard,
and unless you have some very nice, expensive equipment to help,
it is more likely you will damage the board and/or chips. Don't forget to
remove the extra logic chip...
I have two or three 512K logic boards with similair upgrades, and I have
what seems like millions of flyback transformers, disposable 3M static
wrist straps and KillyClip(?? I don't remember what it's called. But I have
tons of parts for them... a buncha empty PCB's, a bunch of clips... no
complete ones, though) type stuff. Very strange collection of parts, all
stuffed away in boxes, still waiting to be sorted.
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