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

[Arthur Flexser]

The problem may not have been the motherboard per se, but rather the fact
that the machine may have had Color Basic 1.0, whose memory test at startup did
not allow for the possibility of 64K chips being in the machine.  The mods
you did may have been something that forced the correct memory map via hardware.

Art

On Sat, 12 Nov 2005, George Ramsower wrote:

> About the rumoured "Half Bad" 64K chips...
> 
>  My first coco was a 4K unit I bought on sale for(I think) $399.
> 
>  It wasn't long before I upgraded to 64K chips and it would not work the 
> upper 32K ram until I modified the board.
>  There was a change in the motherboard I had to make by cutting a couple of 
> traces and wire an unused gate to be able to access the upper 32K. I don't 
> remember now what it was I did then, but suffice it to say that at first, I 
> thought there was a problem with the RAM chips. The original sample 
> schematic provided by Motorola at the time showed the difference from the RS 
> schematic. I just made the coco do what Motorola intended.
> 
>  Perhaps there were defective 64K chips used, but in the case of MY coco, it 
> was the motherboard. 
> 
> 
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