---
title: "LDOSFI.CX ZX81 Larken Fix"
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slug: "ldosfi-cx-zx81-larken-fix"
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markdown_url: "http://localhost/article/ldosfi-cx-zx81-larken-fix.md"
published_at: "2026-01-23T13:32:53+00:00"
modified_at: "2026-01-23T13:32:53+00:00"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
excerpt: "When my Larken ZX81 disk controller arrived I got the 5V DC power wired to the ZX81 controller board. But the most action I got was the drive light would come on at anytime that LDOS went to the drive but the drive motors never came on. After double checking and making sure I had…"
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  - name: "Donald Lambert"
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  title: "CRAGIST Newsletter"
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  - name: "Donald Lambert"
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    title: "CRAGIST Newsletter Jan-Feb 1990"
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pages: "4"
pubdate: "Jan-Feb 1990"
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  - id: 36822
    title: "Larken ZX81 Disk System"
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---

# LDOSFI.CX ZX81 Larken Fix

When my Larken ZX81 disk controller arrived I got the 5V DC power wired to the ZX81 controller board. But the most action I got was the drive light would come on at anytime that LDOS went to the drive but the drive motors never came on. After double checking and making sure I had the terminator resistors in place I called Larry and he said the the drive select line had to go to ground. It was a clue but not one I could use.