File:Ferranti Archives ZX81-UNK-SCH-135 Pencil board layout for a ZX81 16K dynamic RAM expansion.pdf
Summary
[edit | edit source]A pencil board layout on 0.1-inch graph paper, with eight red pencil lines, for a ZX81 RAM expansion. It shows a row of eight 16-pin memory footprints with bussed lines and one red line from each (taken to be the eight 4116 dynamic RAMs and their data bits), a 16-pin device labelled with 74LS157 pin names, an "FX3280" transformer with its converter components (R1, R2, C1 to C5, D1, D2), and an edge-connector pattern labelled with the ZX81 expansion bus signals (5V, 0V, D0 to D7, A0 to A15, MREQ, RD, WR, REFSH). It is the layout for the circuit drawn in ZX81-UNK-SCH-140 and ZX81-UNK-SCH-141: the converter designators and transformer pin letters match those drawings. The sheet carries no title, date or name. Part of the Ferranti Archives 2026.
Archive record
[edit | edit source]| Catalogue ID | ZX81-???-SCH-135 |
|---|---|
| Date | Undated |
| Origin | UNKNOWN |
| Document type | Schematic/Diagrams |
| Device or subject | ZX81 Memory Expansion |
| Catalogue description | A pencil sketch on squared paper of what appears to be a layout for a ZX81 memory expansion of some kind |
| Original file name | {{{filename|}}}
|
| Found in | ZX81-FER-FOL-142 |
| Pages | 1 |
Source
[edit | edit source]Ferranti Archives 2026, original scan on Google Drive.
Author
[edit | edit source]Unknown
Licence
[edit | edit source]Ferranti Archives 2026: source and terms of use
This scan is part of the Ferranti Archives 2026, a collection of Sinclair-related documents from Ferranti's files, catalogued in 2026 and released through the Happy Little Diodes YouTube channel (video, catalogue). The archive presents the documents for preserving and archiving material of historical interest, and for non-commercial, educational and archival research. Its terms state that consent is strictly limited to non-commercial use, and that any commercial exploitation of the documents or their contents, including use in connection with the manufacture, marketing or sale of goods, is strictly prohibited by Sky UK Limited.
Copyright remains with the rights holders. The file is not freely licensed and is hosted here for preservation and repair reference only, under the archive's terms. Personal information was redacted by the archive before release; if you find any that remains, please tell [email protected].
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Dimensions | User | Comment | |
|---|---|---|---|---|
| current | 11:00, 18 October 2026 | 0 × 0 (1.1 MB) | Josh (talk | contribs) | Ferranti Archives 2026: ZX81-UNK-SCH-135 |
You cannot overwrite this file.
File usage
There are no pages that use this file.