Formatting problem with Atari 1050

Hi guys,

I am having a strange problem.

I have a Happy modified 1050 drive and it will no longer read/format dual density disks. I can still read disks that were formatted in single density, but that's it. This just happened out of the blue after transferrring some disks using APE.

I unplugged the APE device and turned the Happy mode off and it still is doing the same thing.

Any thoughts on why this is happening and how I can fix it?