[sdiy] Digidesign Focusrite control 24 schematics

[H.Sergio Alves]

Yes I do have pictures of microscope of the die and the digits but can’t
send them here due to size.. gonna upload them to my server and send a link
;)

I’d really love to use these orange displays for some of my modules
On Thu, 11 Jun 2026 at 19:36, grant musictechnologiesgroup.com <
grant at musictechnologiesgroup.com> wrote:

> Now I know what you are talking about.  " High‑intensity, four‑character
> LCD displays above each rotary control."
> We thought you were talking about the 88888888 7-segment LEDs.
>
> https://www.ebay.com/itm/175869901982
>
> Do you have better pictures of what you have torn apart?  There are, what
> appear to be, a lot of little MCUs in that "board". Maybe just programmable
> logic chips.
>
> GB
>
>
>
> On 6/11/2026 8:04 AM, H.Sergio Alves wrote:
>
> I’ve been trying to reverse engineer it… I have a bunch so one was the
> victim… unfortunately since I don’t have enough knowledge I’ve resorted to
> ChatGPT to help…
> I’ve managed so far to pin out basics and get the circuitry on the lcd
> sorted now it’s the way it works that we struggling with…
>
> The lcd is composed by 4 digits on a 8x5 dot matrix with a custom die on
> the base of the glass
> It’s controlled by a small Zilog through (?) a HEF4053.
> Next step is going to be reverse engineering of the main board where these
> are installed and figure out the pinout for the lcd itself… then using a
> more modern mcu try to speak and show some digits…
> Long way to go but tons of fun so far… and learned a lot :)
>
> On Tue, 26 May 2026 at 14:05, grant musictechnologiesgroup.com <
> grant at musictechnologiesgroup.com> wrote:
>
>>
>> Standard single-digit guys if this is what you are asking about:
>>
>> https://www.ebay.com/itm/175869902159
>>
>> GB
>>
>> On 5/26/2026 5:31 AM, Roman Sowa via Synth-diy wrote:
>> > Are you sure they are LCDs? If so my first bet would be on typical
>> > HD44780 interface. From the blury pictures I see they look to me a bit
>> > like LED matrix, something like HDSP2131 - but those are 8 digits.
>> >
>> > My secong guess is that any customization was related only to size,
>> > leaving control protocol the same as common displays.
>> >
>> > Roman
>> >
>> > W dniu 2026-05-26 o 14:00, H.Sergio Alves via Synth-diy pisze:
>> >> Long shot but does anyone have the schematics for this monster
>> >> controller? Spoke with Avid and Focusrite and none of them have them
>> >> (I know it’s wild but hey…)
>> >> I’m looking to reuse the small 4 digits lcds but need to figure out
>> >> how they’re connected and the protocol used to speak with the Zilog..
>> >> spoke to the manufacturer of the screens but since these were made
>> >> custom and over 20 years ago they don’t have any documentation
>> >> available anymore.
>> >> Thanks for any help you can provide In advance :)
>> >>
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>
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