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Old 21st Mar 2021, 12:10 pm   #190
ortek_service
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Join Date: May 2018
Location: Northampton, Northamptonshire, UK.
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Default Re: I found it! A very sorry looking MK14.

Well it's normal convention to letter-label gates in ascending pins used order. But it does seem SoC have just assigned letters from top to bottom on (Iss.4? / 5? at least) schematic, that does have pin numbers (unlike earlier 'Remove from Book' Issue 1? / 2? one in the V1 manual).
I've not found any other versions on the 'net so far (But I presume SoC wouldn't have changed the connections of the existing circuit unnecessarily, and just added the odd extra).

And it seems SoC had chosen which gate to use on PCB connections, based on what made tracking to it easier, so often made their schematics difficult to tie-up with the PCB if they weren't clear with actual pin numbers and standard labels.


Chris Oddy's replica (based on Issue 5, with PCB tracking kept as close to original as possible), schematic also has A8 is to pin 13, A11 to pin 12 on IC16 - which he's labelled IC16.4, seemingly using ICxx.(1-4) to avoid confusion with SoC's letter allocations:
http://theoddys.com/acorn/Replica%20...0Schematic.pdf
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