[Coco] Floppy controller - 7416 failure symptoms?

Darren A mechacoco at gmail.com
Mon Nov 1 01:37:22 EDT 2010

On 10/31/10, Mark Ormond  wrote:
> Still trouble shooting floppy problems and was wondering if anyone can tell
> me type symptoms that failing 7416 chips would have in a controller?
> It's a fd500.

The two 7416 chips are primarily responsible for inversion of the
drive control lines.  Symtoms could include failure to produce proper
Motor On / Drive Select signals and stepper motor pulses.

A couple of the gates are also used for the NMI* and HALT* lines.  The
computer would likely freeze up or crash during disk I/O if one of
these signals were compromised.


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