[Coco] CoCo 1 'E' board memory upgrade

[Alex Evans]

Have you checked whether or not the machine has a good and accessible 64k
rather than just 32k?

On Tue, Apr 16, 2024 at 8:54 AM Brian Blake via Coco <coco at maltedmedia.com>
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
>
> --
> Ohioan by birth, Mainer by the grace of U-Haul and a short-lived job...
> --------
> Sarcasm is the body's natural defense to stupidity.
>
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