Re: GS memory expansion

[spec@vax2.concordia.ca (Mitchell Spector)]

In article supertimer@aol.com (Supertimer) writes...

>"Jim Thompson" <pdsrome@roman.net> wrote:
>
>>Also, did Apple only make 1 or 2 meg cards? Is there a way to tell which
>>card is which?
>
>Apple only made one memory card, a 1MB one.

    Well, not exactly. In North America they sold a 256K card that
was expandable to 1 MB (there were 24 empty sockets). This is what
most of us are familiar with, and is part number '820-0166-B'.

    Apple made another 256K card that was sold in Australia as well
as New Zealand (not sure about elsewhere) which was smaller and had 
no sockets to add more chips, thus was stuck at 256K. It had a part 
number that read 'A661-0256'. The "A" in the code may very well have 
stood for Apple Australia, meaning it was unique to that region.

>total for maybe a buck each (1MB 30 pin SIMMs are cheap) is not
>a bad investement.  Besides, 286 units used 1MB 30 pin SIMMs,
>so you can probably find them in junked ATs.

    Most of the 286 motherboards I've come across use DRAM chips
in a 16-pin DIP package (the very same used in the Apple memory
card, although not necessarily of the same refresh order or of
the same bit density). Often, if you want to search for SIMMs to
salvage off PC boards, you have to start with 386 boards and up.
I'd say it's rare to find a 286 board with SIMMs, and if you do,
chances are they'd be 256K SIMMs (the IBM PS/2 Model 30 I have
uses 256K SIMMs, though that oddly enough is an 8086 XT).

    Macintosh Pluses and up are also a good source for salvaging 
1 MB SIMMs (those upgraded anyhow), though your less likely to 
find a bin of junked Mac boards than you are of PC boards.

Mitchell Spector
spec@vax2.concordia.ca