I'm having issues with my IIc drives. It reads from all the drives without issue, but not write to the internal, extrenal, or Floppy Emu in either location. Based on some forum sleuthing and my own investigations, I suspect that the issue is with the IWM. I'd love to have a second opinion on that diagnosis.
The story so far... I rescued my family's old Apple IIc from my mother's basement last month. It hadn't been used in at least 15 years, but was stored in a dry, climate controlled environment. Once I got it, I opened it up to take a look at the internals to make sure there wasn't any obvious damage. Other than being a bit dusty, it looked good, so I tried booting from floppies, and was successful. Played a few games and opened Appleworks successfully. It did not occur to me to try saving a file at the time, but since it seemed to be in order, I ordered a Floppy Emu. I also ordered a ROM upgrade (ROM 4), and installed that without any issues as mine had the original version ROM 255.
Once the FEMU (and BMOW's IIc internal/external switcher) came, I set it up and tben booted with the FEMU without any issues. It worked as expected, so I decided to start by copying files from the old floppies to the FEMU. Immediately I encountered various issues whenever what I did required writing to the drive (formatting, saving files, copying files, etc.). Also tried writing on the internal and external floppies for the first time, but encountered the same issue.
Things I have tried:
- Cleaning the drives.
- Using a different SD card in the FEMU
- Using various drive setups, in isolation and in combination.
- Swapping out the FDD cables
- Resoldering the internal and external drive connections on the motherboard. Continuity tests with a multimeter are fine.
- Resoldering all the ICs on the internal analogue board. Continuity tests with a multimeter are fine.
Things I have not tried:
- Redoing the capacitors on the main board or the drive board.
- Swapping out any ICs, other than the ROM.
- Swapping out other known working drives, as I don't have any
- Doing any tests of the installed ICs
At this point the testing (and solutions) are becoming more expensive, and I'm unsure how to proceed. Because this happens with multiple drives, I suspect an issue with the motherboard, likely the IWM. I'd like to test it to be more conclusive, but am unsure how. I welcome any advice on things I may have overlooked or next steps. Thanks!