Mac 512k

From: Brian Wheeler <bdwheele_at_indiana.edu>
Date: Fri Feb 1 12:15:34 2002

On Fri, 2002-02-01 at 13:14, Fred Cisin (XenoSoft) wrote:
> On 1 Feb 2002, Brian Wheeler wrote:
> > > > old solder on new chips over the old ones trick.
> > Partly cloudy. My dad did the 32K->64K upgrade on the coco1, and it
> > required the 2nd bank of 32K to be soldered on top of the 1st bank :)
> > With some motherboard trace cuts thrown in for good measure.
>
> Can you tell us the part number for a 32K RAM?
> (Rhetorical question - TANSA)
>
>

Been way too long ago...I was just excited to get Extended Color Basic
for my birthday :)


> The original Coc was 16K; getting THAT up to 32K could be done by
> piggybacking, or by putting in 64K chips with some minor trace cutting and
> jumpering.
>
>
> Going from 32K to 64K requires reconfiguring the hardware to see the rest
> of the RAM in the "32K" chip that was actually a 64K, and sometimes
> required replacing the 16K (or double 16K) chips with 64K ones. Some
> people reported running into some 64K chips that RS was using as 32K that
> may have been defective and had to be replaced to access the full 64K.
>

Hey, I think the fog is clearing. Seems we had the 4K model, which was
upgraded to 16K shortly after we got it. I got extended color basic for
my birthday, which required 32k, so we must have done the stack with
that. Later we had memory problems and moved to 64K...which would
explain why I'm having flashbacks of 8 (or 9) piggyback chips with some
extra leads between them sitting on a shelf in my dad's workroom, since
he never throws anything away.

I'm going to check around home, seems I remember coming across the
instructions for the upgrade somewhere...

Brian

>
> I let Dr. Marty do the upgrade on my early Coco. He was always overjoyed
> to have an audience when he worked.
> He also hooked up the BNC for me for composite video.
Received on Fri Feb 01 2002 - 12:15:34 GMT