[rescue] Sun 3/50 scsi boot string

[Kurt Nowak]

Very helpful! Thanks Chris! I'm not very familiar with Atari TT gear but I
will look into that when I get back to that part of the 3/50.

On Fri, Jan 6, 2023 at 4:43 PM Chris Hanson <cmhanson at eschatologist.net>
wrote:

> On Dec 26, 2022, at 11:06 AM, Kurt Nowak via rescue <rescue at sunhelp.org>
> wrote:
>
> > Yes, driving the display on my 3/50 will be another little side project.
> I got some hints from others here and ordered a DB-9 breakout connector in
> order to mod a VGA cable to make a custom interface dongle. I want to avoid
> having to get a CRT monitor as space is always a premium. The Dell 2007fpb
> I have seems to drive a plain bwtwo (13W3 version FB), so I don't see why I
> can't get the 3/50 to work on it as well. Thoughts? I know - not very
> "vintage" but I have to find a happy medium.
>
> If your 3/50 uses ECL rather than TTL monochrome, you can adapt one of the
> Atari TT high-resolution video adapters for it. The Atari TT
> High-Resolution Monochrome Monitor was essentially identical to the Sun ECL
> monochrome monitors, down to the pinout on the monitor end of the cable;
> the TT has a VGA connector but something in the connector says that the ECL
> display is connected.
>
> So you’d just wire the Sun DE-9 *output* pinout to the TT VGA *input*
> pinout on the adapter, and then plug your LCD into the “regular” VGA
> *output* pinout on the adapter.
>
> All the adapter really does is take the ECL differential video signal and
> use it to produce an RS-170 video signal (0 to +0.7V peak to peak); the
> sync signals should work as-is because they’re TTL. It should barely
> require any electronics, though what it does require needs to operate at a
> couple hundred MHz due to the bandwidth that 1152×900 (or 1600×1280!) video
> demands. So a 0.7V supply for the signal to modulate and a transistor or
> two to do the modulation based on the ECL input should be it.
>
>   — Chris
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