Editing File:Sinclair ZX Spectrum Issue 3 circuit diagram.png

{{Information|Description=Sinclair ZX Spectrum Issue 3 main board circuit diagram. This is the board the body of the [[Sinclair ZX Spectrum Service Manual]] describes. It shows the PWR socket feeding C50 (22 uF) and the 7805 with C34 (22 uF) on its output; the TR4/TR5 inverter with its toroidal coil; D15 (BA157) and C44 (100 uF) producing +12 V for the 4116 RAM, with R62 and C45 giving the quieter +12VA rail for the colour circuits; and the C46 / D11 / R55 / D16 (5V1) / D12 / C47 chain that produces -5 V. It also carries Sinclair's own edge-connector pinout table and the note that the Issue 3B board changes R60 to 270R, C49 to 560 pF and adds C77.|Source=Sinclair Research Ltd; mirrored in the Sinclair ZX Computers Archive at k1.spdns.de.|Author=Sinclair Research Ltd|License=Used for archival / educational purposes with attribution.}}
[[Category:Sinclair Computers]]
[[Category:Schematics]]