I just purchased a Apple IIc.
Everything seems to work well.
I tried the Apex II Apple II diagnostic from Asimov. Every test was successful - but the Disk PROM controller test was not.
I tried about 25 different disks and all are booting and working without problems.
So the question:
Is the Apex II test not able to test an Apple IIc internal disk drive? Which differences are between the Apple IIc internal disk drive and the Disk II?