Some JCXA-733/JCMA-733 were shipped with the DEC RLV12 RL01/RL02 controller and RL drives. I saw many damaged the RLV12 installed in JCXA-733/JCMA-733 systems. Once the RLV12 is crashed, it is impossible to access any RL drive. The ZRLBC0 diagnostic program shows the MAINTENACE SEQUENCE failure. As far as I remember, all damaged RLV12 was located above the QNIVERTER. So, I guess the damage is caused by the order of modules in the Q-bus backplane.
Bandade
I placed the RLV12 controller bellow the QNIVERTER as showed in the figure.
