Re: Help Identify this RAM Card

[dempson@actrix.gen.nz (David Empson)]

witka <witka@v-wave.com> wrote:

> My //e has 256K ram (or so AppleWorks tells me), I have an 80 column
> card which would bring the total to 128K then I have another card which
> obviously adds another 128K.

Probably not.  If you have two types of memory expansion card,
AppleWorks will only use one of them (hopefully the larger).

> It says "AII Memory Expansion Apple Computer".

That is Apple's standard memory expansion card for 8-bit Apple II models
(II+ and IIe).  It can also be used as a RAM disk in a IIgs.

It is usually called the "Apple II Memory Expansion Card".

It supports 256KB, 512KB or 1MB of RAM.  (It might also work with 768KB,
but I've never had one for long enough to experiment with this.)

> It has an IC with serial number 341-0322A

That will be the EPROM.

> and it has 32 slots for smaller memory chips of which 8 are currently
> occupied by memory chips with the markings "Malaysia 8520 HM50256-15
> U1000888".

Those are 256K x 1 bit, and they must be installed in groups of eight.

> As well it has a larger *empty* chip socket with the markings "539 V
> 798 8 7512-0616   344-0601"

I have no idea what this is supposed to be.  The "344" prefix suggests
that it supposed to be a custom Apple chip rather than an EPROM.

What shape is the socket?  Is it a square pack or dual-in-line?  If it
is dual-in-line, is it the same width as the RAM sockets, or is it about
twice as wide?  How many pins does it have?

I don't have a manual or picture of the card handy, but my recollection
suggests that the card should have a single square pack chip and an
EPROM, both in sockets, as well as the RAM chips (and possibly some
miscellaneous 74LS series logic chips).  I don't remember seeing another
empty socket.

The square pack is necessary for the card to work at all, and it
wouldn't be recognised by the computer if the EPROM was missing.

> My question is what is the maximum I can add to this card - i.e. if I
> were to fill the 24 other little memory slots and the empty IC socket
> what would I have?

Just filling all the RAM sockets would give you 1MB.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand