---
title: "SCLD Character Select Switch Schematic"
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published_at: "2026-03-15T00:58:19+00:00"
modified_at: "2026-03-15T00:58:19+00:00"
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excerpt: "Technical schematic (DRW No. SRC 0549) showing the wiring for a character select switch for the Sinclair ZX81 SCLD chip, allowing selection between character sets. The diagram includes pin assignments for the US connector and the SCLD chip, with an alternative IC noted. The listing was created 9/17/87."
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  title: "Timex Sinclair Users Group Mile High Chapter Newsletter"
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    title: "Timex Sinclair Users Group Mile High Chapter Sep 1987"
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pages: "7"
pubdate: "Sep 1987"
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---

# SCLD Character Select Switch Schematic

Technical schematic (DRW No. SRC 0549) showing the wiring for a character select switch for the Sinclair ZX81 SCLD chip, allowing selection between character sets. The diagram includes pin assignments for the US connector and the SCLD chip, with an alternative IC noted. The listing was created 9/17/87.