7900A drive: 1 , Me - 1/2

The score narrows, but I can't claim a complete victory.... Tony wrote... I went through the schematics, concentrating on the PMR board (Power regulator) and Drive control board. Not in great detail, but just enough to get a general gist of the sequence of events and "who does what". I then went down and checked the disc power supply (it's a separate rackmount unit). Then before starting to follow traces and wires I decided to pull all the connections from the rest of the system to the PMR board. I was specifically looking for wires that had come loose, or pins that weren't pushed all the way in the connector, etc. Double checked that my hand written labels on the connectors (done before removing them) showed that all the connectors were back in the right place. Powered the drive up - heads seeked and drive ready came on. Hit the unload switch, and the heads immediately retracted and the brake engaged. Did this about 10 times in a row, every time the heads retracted nicely just like they're supposed to. Hummm... this leads me to one of two possible conclusions: A) there was just a loose connector, or B) this is a total co-incidence that it started working and the problem might very easily happen again. Now that it's working, further troubleshooting to be sure of the exact cause is not easy. I Know I had all the connectors pushed down firm and in the correct place before, but, it does work now (at least 10 times anyway, my luck the 11th time would have been the failure). Followup questions: 1) The drive innards are dusty again, must be the environment (or running with the covers removed didn't help I guess). What is the best way to get all the dust out? Canned air doesn't begin to get the dust off the plastic surfaces, neither does a DP-style vacuum. Any tips/tricks anyone would care to pass on? 2) From the previous spin-down with the heads on the platter, the bottom heads are mint but the top heads now have oxide streaks on them. Cleaning with foam qtips and IPA doesn't budge any of it. I am loath to take out the top heads (removable platter) and send them out for recontouring and test-fly because then the drive will need to be re-aligned and I don't have an alignment cartridge (and probably the know-how) to realign them. This is only important because I have a diagnostic cartridge that I need to be able to read for additional cpu/disk/tape diagnostics on down the road. Is it the general consensus that heads in this condition are ok to use or am I setting myself up for a major problem. What I'm hoping is on down the road to get the diagnostics copied from cartridge to 1/2 tape. Then I can send the heads off and not bother with re-alignment (other than having to reformat my cartridges and lay data from tape back down. Bad idea? Thanks! Jay West