"No Disc" - how I hate lying computers, "no data" - fair enough.
Dull red laser spot, focus and sledge operate correctly, spins up, until
stopping after third attempt. Cleaned lens, and internal cover glass. Good
cap ESR, both ribons check continuity ok.
Tried adjusting power pot a bit but no change.
Pushing the sledge cog around either way , the servo will return it, so
focus presumably ok.
Sometimes it will sit with "reading" in the display permanently and disc
spinning almost top speed until switched off. Where to go next? I've another
(salvaged) KSS 213E, unkown condition , will try replacing but I suspect
something more downstream.