Disk II - Drive Running but shows 0 RPM

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Disk II - Drive Running but shows 0 RPM

Hi Everyone,

Using Apple II software diagnostic tools to test a Disk II floppy drive. Interestingly trying to calibrate the disk speed the unit is returning 0 RPM (but you can hear the drive actively seeking and the red light on front of drive is illuminated). I was hoping someone might be able to point me in the correct direction of what part of the circuit is responsible for calculating drive speed.

Thanks all!

 

 

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Check that the belt is there

Check that the belt is there.  You might be hearing the motor running but the spindle might not be moving if the belt is broken or has fallen off.

Just a suggestion...

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macnoyd wrote:Check that the
macnoyd wrote:

Check that the belt is there.  You might be hearing the motor running but the spindle might not be moving if the belt is broken or has fallen off.

Just a suggestion...

 

This is a common occurrance.  If you have the cover off the drive you should be able to see if the spindle is turning.  You need to have the cover off to adjust the speed anyway.  At least unless someone drilled a hole in the appropriate place to allow access to the speed adjust trim pot w/o removing the cover.

 

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Drive belt is in place and I

Drive belt is in place and I can see the floppy rotating (Case is open). Interestingly today I found the drive speed was reporting but varying widely from 100RPM -> 400RPM. The drive motor is making a constant noise which i can adjust with the trim pot you speak of. I'm sure I read another post with a similar problem, trying to find it again now...

 

 

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If anyone comes accross this

If anyone comes accross this problem in the future. I have managed to resolve this by cleaning the head on the floppy drive and using a known working floppy (not one that fails to format). The drive speed is now consistent and looks like I can now read disks from this unit.

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Congrats!

Congrats!

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