[Coco] 26-3134b

[Ed Snider]

Yes Henry, that's right.  If you have a 'B' type CoCo2 with the single ROM chip 
that hasn't been upgraded to extended basic, you'll need to burn a new rom 
chip and remove / install jumper wires.

A standard 28 pin, 16K eprom (27C128 or similar) can be used.

Extended BASIC 1.1 goes in the lower 8K of the chip, and Color BASIC 1.3
in the upper 8K.

For your convenience, here is the appropriate rom file...
https://drive.google.com/file/d/1cJlwDWX9EVv4-wAlFM_uLK0wUsLgzOu-/view?usp=sharing <https://drive.google.com/file/d/1cJlwDWX9EVv4-wAlFM_uLK0wUsLgzOu-/view?usp=sharing>

And here is a picture of an upgrade I did on one, showing the jumpers...
https://drive.google.com/file/d/14u3wsHucg8d-pJclRlLooJRboT0ZPiqu/view?usp=sharing <https://drive.google.com/file/d/14u3wsHucg8d-pJclRlLooJRboT0ZPiqu/view?usp=sharing>

There are five jumper wires that will need to be removed and rewired to the 128K position.

- Ed


> On Nov 25, 2020, at 4:17 PM, David Ladd <davidwladd at gmail.com> wrote:
> 
> Henry,
> 
> Ed's ECB in the 24to28pin adapter is designed for the CoCo 2's and CoCo 1's
> that have the empty 24 PIN ROM socket.
> 
> If you pull the Color Basic ROM and install his ECB ROM upgrade then the
> CoCo would not startup.
> 
> Color Basic sits at $A000-BFFF
> 
> Extended Basic sits at $8000-9FFF
> 
> Later CoCo2's that have a 28PIN ROM have Color Basic and Extended Color
> Basic in one chip.
> 
> At least from the service manual I can find for the model # you provided
> shows a U13 where the Extended Color Basic ROM is to be installed.
> 
> On Wed, Nov 25, 2020 at 1:59 PM rietveld rietveld <rietveldh at hotmail.com>
> wrote:
> 
>> Can a coco 26_3134b's stock color basic 1.3 rom be replaced with Ed's ECB
>> rom that he has on his website?
>> 
>> Sent from my BlackBerry — the most secure mobile device
>> 
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