5.25 floppies that read but don't write

dwight dkelvey at hotmail.com
Wed Aug 19 22:24:56 CDT 2015

As a general rule, you should not write to a DD disk with a HD drive.
It does not erase the full width of the track.
You should only write to DD from a 360K type drive.
If you must write using an HD drive, it is recommended that you
first completely erase the disk with an external magnetic media
eraser. Then when formatting, make sure you select the option to format
as a 360K.
It still may not read well on a 360K drive but that is life.

> Date: Tue, 18 Aug 2015 21:30:31 -0700
> From: cclist at sydex.com
> To: cctalk at classiccmp.org
> Subject: Re: 5.25 floppies that read but don't write
> On 08/18/2015 09:05 PM, Marc Verdiell wrote:
> >
> >
> > I have connected a 1.2M 5.25" floppy to my computer. After a bit of
> > jumper learning and setting, it's recognized and reads my old DD and
> > HD floppies fine. But for the life of me I cannot write to it. Not
> > under DOS, Win98, or WindowsXP. Which all read fine.
> Make sure that "WRITE GATE" goes low (use a logic probe) on pin 24 of 
> the drive while you do your write.  If so, your floppy write circuitry 
> has a problem.  I.e., it's not the cable.
> --Chuck

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