MTI MXV22M

Does anyone have experience running the MTI MXV22M? It's a dual-height QBus card that emulates RX02 but uses a 5.25" 96 TPI drive. I've got a small heap of them and we're trying to get them going. When trying to format diskettes using the process documented in the manual, the drive selects for maybe a second then deselects, and we get a drive not ready error. The controller isn't using the ready line, as the SA-460 for which it is designed doesn't supply it. No traces physically connect to pin 34. Since we're close to out of ideas, we've also plugged in a pair of Shugart SA-800s, on the idea that maybe the MXV22M is close enough to the MXV22 to show some signs of life. It doesn't give a drive not ready error, and it will step the heads like it's really formatting, but never loads the heads. Happy for any input on this one! Thanks, Jonathan