HP 9895A Part 2: Epic Controller Board Repair (and a transparent chip surprise)

We restore more HP 9895A dual 8" diskette HP-IB drives, but these will be way more challenging. We'll need a full on logic analyzer assisted repair to debug a really, really nasty fault. It's a long video, but don't miss the intermission where Master Ken inspects a transparent silicon-on-sapphire chip!

Many thanks to HP enthusiast Craig Ruff for the ROM dump and disassembly.

8" Floppy Playlist:    • 8" Floppy Diskette Drives  

HP 9825 Playlist:    • HP 9825 Repair  

Ken's Silicon-on-Sapphire chip blog post: http://www.righto.com/2023/12/HP-sili...

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"Elevator Music" Credit: Crinoline Dreams by Kevin MacLeod

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