[vcf-midatlantic] Orig Mac disk drive does not stop/bangs head

Herb Johnson hjohnson at retrotechnology.info
Thu Nov 29 11:58:45 EST 2018

> when I power on my orig MAC the drive races to the
> front and attempts to keep going... is there a fix?

My guess is, this is a Macintosh 128K and "the drive" is the 400K floppy 
drive. "the fix" is to diagnose the problem.

Try another 400K floppy drive externally, or a 800K external floppy 
drive - see if they work the same way. If so, you may have some kind of 
68000 processor motherboard problem. Or a loose internal floppy cable.

If external drives work, then see what's going on with that internal 
drive. Maybe the track 00 sensor is bad or its little cable isn't 
connected well. Or the head stepper has lost a phase and is running 
backwards (desperately seeking track 00 while running to track 99).

"The Dead Mac Scrolls" suggests if the screen is dark and you have odd 
behavior, you may need to fix/replace the analog card, specifically the 
flyback transformer. But you'd likely report a dark screen, so that's 
not likely the problem. The book doesn't seem to list your floppy drive 


Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net

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