8-inch drive substitutes

I took the OP's question a bit differently, I guess. I read it as "If I can't find a Qume 842, is there any reason that I can't use a different drive, all else (power supply, mounting holes, connectors, bezel, etc.) being the same?" Golly, if you want "different", some of the old Japanese drives were really bizarre. Not to mention drives with 3-phase positioners, radial select, onboard data separators, etc. Or drives with the occasional inverted control line--or power supplied through the 50- pin drive connector (e.g. Calcomp). But if you can find a drive that matches up in physical characteristics and takes the same power supply--and has a reasonable set of configuration jumpers, the big gotcha is seek rate, no? A drive without a door-lock solenoid isn't really going to bother you, nor is one that doesn't have an auto-eject feature. But you can't really do much about seek rate unless you want to hack the software. And if the seek rate is too slow (doesn't apply here, since the 842 is a pretty fast drive) for the new drive, operation will likely be extremely noisy. Cheers, Chuck