All, A number of years ago, I ended up with a pile of MXV22M QBus controllers, which present a RXV21 compatible interface to the QBus, but talk to 5.25" diskettes. Thanks to a generous loan of a regular MXV22 from John Ball, I was able to convert the MXV22M to a regular MXV22: http://users.glitchwrks.com/~glitch/2026/07/12/mti-mxv22m-conversion The above writeup includes links to the fuse PROM images. I'd like to build a mezzanine to replace the 7x fuse PROMs with modern EEPROM or Flash, but haven't had time to get on it, other than verifying that the original fuse PROMs aren't so fast as to make that impossible. If you have blank fuse PROMs but no way to program, contact me off-list and I can blow a set on the Data I/O 29B. I will be going through the MXV22Ms I have and converting them, as time permits, and then making them available for sale. If you want an untested MXV22M to convert yourself (cheaper if I don't have to!) then contact me off-list and let me know. Thanks, Jonathan