PC diskette drives in a HP 9122C was WTB: HP-85 16k RAM Module and HPIB Floppy Drive

I have managed to get 2 PC type drives working in a 9122C they are two different versions of the YE Data YD-702D.? The important thing is the drive needs to provide a ready signal, diskette change and density.? Most drives provide the last two but do not have a ready signal.? You also need to leave pin 1 unconnected this is a signal from the controller to reset the diskette changed signal.? One of the drive the YD-702D-6037 can also be altered by moving jumpers to get power from the cable.? The other a YD-702D-6537D does not and it unfortunately seems to be the more common drive.? I changed the drives so that ready is on Pin 34, diskette change on pin 2 and density on pin 4, the same as the Sony drive in the 9122C.? I did encounter one problem where if I tried to CAT a diskette it would always report that the diskette was changed or missing and I recall encountering this previously, it may be related to how the diskette changed signal gets reset. On most "standard" 3.5" drives the diskette changed signal gets reset as soon as the drive is selected and receives a step pulse. On the Sony drives used in the 9122C reset the diskette changed signal by a pulse on pin 1 from the controller.? What I think is happening is when media is changed, the controller thinks it does not have to move the head so the diskette changed never gets reset so the controller continues to think the diskette has been changed, I will do more testing to verify.? I thought that booting with the drive empty provoked this but that is not the case.? I can post details of the modifications to the drives if anyone is interested. Paul. On 2017-11-17 1:26 PM, Paul Berger wrote: