[Coco] The Pepper board, a replacement circuit for the SALT chip.

[Rocky Hill]

 Thank you David, I really appreciate that!

Pedro
    On Tuesday, October 4, 2022 at 02:51:52 PM EDT, David Ladd via Coco <coco at maltedmedia.com> wrote:  
 
 Thank you for all your hard work in designing these projects and making
them available to everyone.

Sincerely,
David Ladd
***END OF LINE***




On Mon, Oct 3, 2022 at 10:27 PM Rocky Hill via Coco <coco at maltedmedia.com>
wrote:

> Hi all,
> About a year and half ago I made a circuit board that fully replaces the
> functionality of the SALT chip(Supply And Level Translator)that the CoCo
> 2's and CoCo 3's use. This board is a drop in replacement for the SALT chip
> and I call it the Pepper board.
> I designed this board because I needed to bring one of my CoCo 2's back to
> life, always intendingto share the design so that others in my predicament
> could make one and/or improve on the design. Some people have already
> assembled a Pepper board and some have purchased a Pepper from me.
>  The SALT chip is responsible for supply regulation, TTL<--> RS-232
> (serial) level translation,cassette read operations, and driving the
> cassette relay. Without a SALT you can't do any of thatand with a partially
> working SALT you can do some of that.
> the Pepper board offers some benefits other than the obvious one of having
> a working CoCo again.
> 1. The CoCo runs noticeably cooler.The Pepper board uses a switching
> regulator to provide the +5VDC to the CoCo and completely bypassesQ1, or
> the big transistor with the heat sink that gets really hot.
> 2. Uses less power.Because switching regulators are more efficient than
> linear or linear like regulators, it uses less power.
> 3. You don't need a transformer.You can directly power the CoCo via the
> transformer connector with a voltage range of about +9VDC to +40VDC.
> You can probably already directly power the CoCo with +12VDC at the SALT
> chip input,
> but the SALT chip depends on the roughly 13VAC that comes from the
> transformer to provide the -12VDCRS232 level for the bit banger. This means
> that although the CoCo will work, the serial port will not.
>
>
> I just uploaded version 1.1.0.
> This version has a different form factor so that it better fits all of the
> models of the CoCo's I have access to.I've tested it in the Following CoCo's
> CoCo 2's
> 26-302626-302726-3134A26-3134B
> CoCo 3
> https://github.com/qbancoffee/coco_salt_replacement
>
>
> In the next week or so I'll upload some pictures so that you can see what
> it looks like if youdon't want to load the KiCAD project and render it.
> Enjoy!
>
>
>
>
>
> --
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> Coco at maltedmedia.com
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>

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