Floppy failure fix - WIP

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Floppy failure fix - WIP

Post by exxos » Fri Nov 30, 2018 10:23 pm

While there can be a lot of reasons for the floppy drive to fail, such as bad PSU, bad drive etc. If a drive works in a PC but not a STE for example, then its possible the machine may need the fix below.

The short version of this fix , is that the original Atari floppy drives had internal pull ups on some of the signals, drives like the MPF920 do not. So its possible (and likely) All non-original drives will need this modification. It is possible original drives could suffer as well, but this is a very new fix and the "bug" has only just been found.

This issue can cause the drive not to be found, intermittent read/write issues etc This issue is likely present on any machine with a 1772/Ajax floppy controller using a LS06 type buffer. IIRC the MSTE had 1 of these resistors fitted, I need to look into that again..

Below, the points in red need a 1K resistor connecting to 5V.

stemod.JPG (146.09 KiB) Viewed 907 times

I did a quick example below...

IMG_3634.JPG (6.27 MiB) Viewed 907 times
IMG_3635.JPG (5.64 MiB) Viewed 907 times
IMG_3636.JPG (5.42 MiB) Viewed 907 times
IMG_3637.JPG (4.97 MiB) Viewed 907 times
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