Teac FD-54

[Chuck Guzis]

On 2/15/20 10:47 AM, Patrick Finnegan wrote:

> I'm not sure why the index sensors on both are broken, but not the write
> protect notch sensors. Hopefully once the replacements arrive, replacing
> that will fix the drives.  The drives look pristine on the inside.

The biggest (and most misleading) issue with optical index sensors tends
to be dirt.  The phototransistor or LED gets obscured by crud and ceases
to operate, even though electrically, it's fine.

The same phenomenon accounts for many so-called "alignment" issues with
floppy drives--the track zero sensor gets crud and the position at which
the sensor is interrupted changes.   It's a mistake to attempt to
re-align a drive before cleaning the sensor.  In reality, most floppy
drives do not exhibit drifting alignment.

--Chuck