[Coco] Re: [Color Computer] Looking for a Coco I 64k?

[Arthur Flexser]

On Sun, 13 Nov 2005, Mike Pepe wrote:

> Richard:
> 
> > There were modifications to make a CoCo 64K back to the D board (although it 
> > was a pain on the D). I have an E board that was modified to 64K. Tandy 
> > always put 64K chips in for the upgrade to 32K, but they still called it 32K 
> > because that was all you could access from Basic. I've heard that the early 
> > 64K upgrades did use chips that were 'half good', but I don't know how 
> > reliable that rumor was. At any rate, they soon switched to good 64K chips. 
> > Programs that require 64K will run on my CoCo I without issue. Programs like 
> > Telewriter 64 do report back the 64K available.
> 
> The rumor is true. There are actually a couple of official 32k upgrades 
> to the older CoCo 1- one was two banks of piggybacked 16k chips. The 
> other used 64k chips that are "half good". Those boards have a jumper 
> labeled "HIGH/LOW" depending on which half of the chips selected the 
> good 32k bank was on.
> 

That Tandy made the provision on the D motherboard for the possibility of doing
a 32K upgrade using half-good 64K chips doesn't necessarily mean that they
actually sold any machines or upgrades with such half-good chips, though.  Could
be they were just allowing for the possibility of doing so if prices of good 64K
RAMS remained prohibitively high.

Art