Re: New Pile of Mystery Boards

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

Jeff Lemke <lemke@terra.cira.colostate.edu> wrote:

> Seb wrote:
> > 
> > Jeff Lemke wrote:
> > >
> > > 5.  IIEasy RAM Memory Upgrade, Copyright 1989 by PaceMark Technologies,
> > > Inc.  Very small board the size of a business card, on red baseboard.
> > > Only 4 chips, plus some resistors.  How much RAM was this?
> > 
> > What's written on the chips?
> 
> Sorry for the long time in responding.  The two chips on the left are
> labled "P21464-10" on the first line, "K047 KOREA" on the second line.

These are RAM chips, each of which contains 64K by 4 bits.  As a pair,
this gives you 64K bytes.

> The two chips on the right are labled differently from each other.  One
> has "SN74LS374N" on the first line and "XXAB9212" on the second line.
> It's a Motorola chip.

This is an 8-bit latch (actually an 8-way D-type flipflop), probably
used to hold part of the address or the data being written to or read
from the RAM.

> The other chip on the right is labled "Thailand", then a big "S", then on
> three lines is written "74LS245N", "FKN2486", and "9148VF" respectively.

This is an 8-bit buffer, probably used to isolate the data bus on the
card from the motherboard.

Sounds like a IIe auxiliary slot 64K RAM card to me.

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