[Coco] CoCo 1 'E' board memory upgrade

[Bruce W. Calkins]

I can't tell from the picture if the additional wiring is correct.

However; Color Basic, Extended Color Basic and Color Disk Basic cannot 
see more than 32K.

If the machine boots OS-9 level 1 then you are good.

Bruce W.



On 4/16/24 08:53, Brian Blake via Coco wrote:
> Greetings CoConutz!
> 
> A while back, I picked up an E board CoCo 1, with what appears to be a
> Radio Shack 32k upgrade. The original CoCo 1 case was fragged in shipping,
> so it sat in the corner of my room until recently when I had time (due to a
> broken leg) to work on it.
> 
> My plan was to upgrade to 64k, after transferring the motherboard into a
> TDP100 case I from Tony Padroza even longer ago. That is pretty much done,
> as can be seen in the images below:
> 
> https://cmtekwerx.com/transplant.jpg
> 
> https://cmtekwerx.com/testing.jpg
> 
> 
> Where I'm having issues at is combining the Radio Shack 32k upgrade, with
> the instructions from the May '84 Rainbow:
> 
> The work previously done: https://cmtekwerx.com/coco1-pcb.jpg
> 
> The instructions from Rainbow: https://cmtekwerx.com/rainbow-upgrade.jpg
> 
> 
> I'm  pretty sure the upgrade is the Radio Shack 32k upgrade, with the
> following mods done (see coco1-pcb image llnked above):
> 
> U29 pin 1 to U11 Pin 5, and the connections between U4 & U8; U29 Pin 2 to
> pin 8; and U29 pin 3 to U8 pin 21.
> 
> This is where things get fuzzy - fresh 4164's and the 64k addressing
> modification per the May '84 Rainbow, and noticed U29 pin 1 is connected to
> U11 pin 5.
> The article states U29 pin 4 should be connected to U11 pin 5. I'm guessing
> this is in addition to the wire that's already running from U29 pin 1? Or
> should that be removed?
> 
> A little education and clarity would be greatly appreciated!
> 
> 
> 
> Best regards,
> 
> Brian
>