I have an Apple IIgs that has been working just fine. But today, I find the 3.5" drives are not recognized any more, however the eject button does still function. I have two 3.5" drives and one 5.25" drive. The 5.25" drive is at the end of the chain, and it is still working. I removed the 3.5" drives and tried them with my Macintosh 128k, and it recognizes each of them. The Apple IIgs also passed the diagnostic test. What can I do?