File:Ferranti Archives ZX81-FER-NOT-104 Pencil sketch of ZX81 ULA tape input and video output circuits.pdf
Summary
[edit | edit source]A photograph of an A4 sheet of pencil sketches headed "ZX81.", redrawing two of the ZX81 ULA's pin circuits from the Ferranti cell drawing ZX81-FER-SCH-103 with pin numbers and supply voltages added. The upper sketch is the TAPE IN circuit on pin 20 (series capacitor, clamp diodes to 5V and ground, 400 ohm series resistor, 5K to a 0.9V rail, 16K collector load). The lower sketch is the TV/TAPE output on pin 16 (VIDEO and SYNC inputs, an emitter follower with 1K to ground and a 200 ohm series resistor), with the composite video levels written beside it: white 4V, black 2.8V and sync 0V. The sheet is undated and unsigned and carries no company name. The pin numbers match the ULA logic diagrams ZX81-FER-SCH-105, ZX81-FER-SCH-011 and ZX81-FER-SCH-102. Part of the Ferranti Archives 2026.
Archive record
[edit | edit source]| Catalogue ID | ZX81-FER-NOT-104 |
|---|---|
| Date | Undated |
| Origin | Unknown |
| Document type | Schematic/Notes |
| Device or subject | ZX81 ULA (2C158 pin circuits) |
| Catalogue description | Pencil sketches of circuits |
| Original file name | {{{filename|}}}
|
| Found in | GEN-FER-FOL-107 |
| 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].
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| Date/Time | Dimensions | User | Comment | |
|---|---|---|---|---|
| current | 23:12, 16 October 2026 | 0 × 0 (840 KB) | Josh (talk | contribs) | Ferranti Archives 2026: ZX81-FER-NOT-104 |
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