TK50 tribulations

Hi all, I recently dug out a TK50 I was tinkering with before and am having some trouble diagnosing what's up with it. It arrived with a tape stuck in it, but I've since managed to persuade that out and a good clean up had it loading and ejecting properly. Now any read or write just results in a bit of shoeshining, whereafter it goes into its light-show routine. Yes, I should probably just admit defeat and keep it for parts, but it seems so close to working I thought I'd take another stab. The technical manual lists all manner of error codes which should narrow things down. I'm however at a loss as to how one should extract them from the drive/controller. I've had it hooked up to a PDP-11 and XXDP said nothing more than that the drive was faulty. I also have a MicroVAX II (where it actually came from) but I've not been able to run diagnostics on there due to lack of a floppy drive. I did experiment with an RX33, some RX50 images and a PC to write them, but the MicroVAX doesn't want to boot them. Any ideas? Cheers, -- Steve Maddison http://www.cosam.org/