MicroPdp-11 RQDX1 boot problem

Hi folks, I refitted the power supply and put the pdp-11 back together. However when I try to boot the pdp-11 from the hard drive it throws up an error 20 on the console, which says there's a controller error. I can't see what the problem is, though something's not quite right. The RQDX1's diagnostics pass on startup - it shows a sequence of leds, and after several seconds they all go off. The pdp-11 startup tests seem to be OK. My ribbon cables between the pdp-11 appear to be connected correctly. The RD52 drive light pops on briefly on boot (as I would expect if it initially spins up), but oddly I don't see a light popping on on the RX-50 drive (though I seem to remember it did). Any thoughts? -cheers from julz @P ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ