Editing Acorn System 1 Circuit Diagrams

The '''Acorn System 1 circuit diagrams''' are Acorn Computers Ltd's own drawings for the two Eurocards that make up the [[Acorn System 1]]. Three sheets, no text layer.

These are the sheets the [[Acorn System 1 Technical Manual]] lists in its contents as supplied '''loose''' rather than bound in, and the drawing references match the board numbers that manual gives.

== The sheets ==

* '''"6502 Micro Computer P.C.B. Circuit Diagram"''', reference '''200,000/C''', Acorn Computers Ltd — the processor Eurocard.
* '''"Keyboard, Display &amp; Cassette Interface P.C.B."''', reference '''200,001/C''', drawn by CBT, dated '''26-08-79''', Acorn Computers Ltd — the upper Eurocard with the hex keypad, the eight-digit seven-segment display and the cassette interface.
* A third sheet continuing the keyboard/display/cassette drawing.

== What it settles ==

Values are marked against designators on the drawings, so these sheets — not a parts list — are where the System 1's component values come from where the technical manual's lists are ambiguous. Two details worth reading off sheet 200,000/C before working on a board:

* The processor card's on-board regulator is '''IC13, an LM340-T5''', with C8 and C10 either side of it.
* The drawing carries Acorn's own warning that '''C10 and IC13 must be removed before fitting the link''' that bypasses the on-board regulator — a machine fed from an external regulated supply should not have both.

== What these drawings do not contain ==

* '''No parts list and no Acorn part numbers.''' Values are schematic annotations only.
* '''No PCB layout or component location map.''' For board layouts see the [[Acorn System 1 Technical Manual]], which prints them on page 24.
* '''No fault-finding, no test procedure, no power supply design.'''
* No text layer, so nothing can be searched.

== Pages that cite this document ==

* [[Acorn System 1]] · [[Acorn System 1 Maintenance Guide]] · [[Acorn System 1 Troubleshooting Guide]] · [[Acorn System 1 Capacitor Replacement Guide]]

<pdf> File:Acorn System 1 Circuit Diagrams.pdf </pdf>

Download here: [[:File:Acorn System 1 Circuit Diagrams.pdf|Acorn System 1 Circuit Diagrams.pdf]]

== Related documents ==

* [[Acorn System 1 Technical Manual]] — construction, circuit description and parts lists
* [[Acorn System 1 User Manual]] · [[Acorn System Catalogue]]

[[Category:Acorn Service Manuals]]
[[Category:Schematics]]
[[Category:Acorn Computers]]