More Executel phone system news

Adrian Graham binarydinosaurs at
Fri Jun 9 03:20:22 CDT 2017

Hi folks,

Some of you may remember me burning the midnight oil over an 8085-based phone system designed by STC in the UK, the Executel 3910. 

Good news to report! Completely by chance one of the programme managers for STC at the time found all my postings and pictures in a last ditch attempt to give his stash of goodies away before he put them all in the local recycling.

This means that not only do I now have two unused units and spare parts but I also have the machine that was dragged all over the world to trade shows, full documentation, a complete source dump AND the entire 8” disk set for an Intel MDS80 :D

A slight downside is that the code is all written in PLM which I’ve no experience in whatsoever.

Another downside is I now know what’s making my machine loop at startup. Remember the LUCY modem chip? Otherwise known as the SAA5070, my board is sending it an init code and expecting an ‘ok’ result back which it doesn’t get. At least I have 3 other spare chips now.

The final issue is that the unused machines have had their PSUs removed since the ASTEC 8151 was a bit of an achilles heel because of the way it was mounted upside down and only passively cooled, so I’m back on the trail of fixing the spare PSUs I have…

Fun times ahead!

Binary Dinosaurs - Celebrating Computing History from 1972 onwards

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