Weird Lear-Siegler ADM-3A board

[Eric Smith]

On Fri, May 25, 2018 at 1:58 PM, Adrian Graham via cctalk <
cctalk at classiccmp.org> wrote:

> Hi folks,
>
> A friend of mine has said ADM-3A and is baffled by the tiny board it
> contains, not the usual ‘covering entire base’ discrete logic board they
> normally have. Centre of this board is the Nat Semi NS405 ‘display
> processor on a chip’ which is obviously why the board is so small but
> neither of us have seen this before in a 3A.
>
> Anyone else? Pic at http://www.binarydinosaurs.co.uk/tonyADM3a.jpg <
> http://www.binarydinosaurs.co.uk/tonyADM3a.jpg>
>

That's the Zentec ADM3 retrofit:
    http://bitsavers.trailing-edge.com/pdf/zentec/Zentec_ADM3_Retrofit/