<Is it possible for a RQDX3 to be bad, and trash a RD53 (Yes, I know what <terrible drives they are) to the extent they can't be formated in a VS200 Yes and no. Yes I've had drives a VS2k would not touch but the drives were otherwise ok. The PDP-11 formatter would however format them. Most of the drives I have that the VS2k didn't like were formatted on my CP/M crate using a teltek card(oddball format) or the older PC mfm controllers. You could have an incorrect hookup, power problems or other things going on. Are the RD5x's powered from the same powersupply as the rest of the system (in the same box)? RQDX3s do fail though the failure modes can be vary varied as they have their own PDP-11/memory/eprom on board. If it passes self diagnostics it's a 98% safe bet, if it's self testable it's ok. That does mean there are parts that selftest cannot verify. <So my question is, am I just having very bad luck or is the controller m <problem? I think your suffering from a multitude of things and with an apparent lack of docs to reference too. Your trying to attack it was if it were a PC and it's not even close. Those drives generally don't fail that suddenly and my expereince is they are generally reliable. But when you start with a box of junk it's hard to get to a know working point. Me I have Q-bus PDP-11s that can boot faster and off a wider variety of devices so any testing is done that using good old RT-11. I also have a set of diags for that platform so testing things like disks, tapes and interfaces is doable either with diags or by using them. At some point I have know good boards and questionable seperated and can move the known good to the uvax. PDP-11 and uvax Qbus commonality can be handy. Allison