ADTPro hang on Apple IIC

[PacificState]

I'm bootstrapping my Apple IIC (x2) machines with ADTPro running on M2 MacBook Air via an FTDI adapter - and while I can transfer data, I can't successfully write out disks.

The problem is hit whenever I try to write an image via the ADTPro software running on the IIC. Whilst the transfer is initially successful, the machine hangs after writing a certain number of blocks (249 out of 280 in the case of the default ADTPro DOS image) and leaves the drive spinning. I have two IICs, and have replicated this behavior on the second, too.

Can anyone suggest a solution? Thanks in advance!

 

[PacificState]

Update - I think this is an internal drive problem, rather than one with ADTPro, as writing to my external 5 1/4 drive works fine. Things I've done so far:

- Cleaned the heads using a head-cleaner disk (soaked in 99% isopropyl alcohol)
- Lubricated the head rails (if that's the term)
- Adjusted the drive to 300rpm with Locksmith
- Tried writing to different disks

It's now erroring out on block 260, with the head moving repeatedly back and forth - so it appears to be an issue when the head moves near towards the inner part of the disk (if I'm understanding the write pattern correctly). Any suggestions for how to resolve this?