DEC Lab 11/40

You had already gotten a bunch of good responses, you noticed all the foam was falling apart like in mine, I cleaned it all out so bits of stuff wouldn't be floating around. I used some furniture foam where I needed thick and soft weather stripping foam for areas like the air feed to the disk pack. If you pull the fan to replace the foam check to see that the duck bill which cools power supplies doesn't have dust blocking the end. I also had to replace the nicad battery pack which retracts the heads when power fails. If it isn't leaking you can see if it took a charge after the drive has been running a while or try charging if you got a power supply and then load test. You can also test by carefully pulling the head forward with the drive powered off. It will suddenly yank it back when you hit the switch (watch the fingers). Don't pull it far enough that it starts to get to the head load ramp, it should pull back before that. If you think you might have some dropped packs what I do is with cover off watch the reflection of something at the edge of the disk where the head loads. Blip the run switch to start the pack spinning and as it slows down watch for the reflection to move. If so the edge is bent. I don't know how much is safe, I have a couple I declared unsafe and a couple with just a slight change which worked fine. For packs that weren't stored in bags I clean them before using. I use alchohol wipes then "air" can and a lens brush to remove all I can. Look at various angles, the proper lighting angle makes the dust visible. I then let sit in the drive for a while, spin it up then run a program which quickly steps through all tracks. Frequently I get a little ping on a track on the first pass or two but the moving head seems to knock the dust bits off. If the head isn't moving it can sit pinging at a track which doesn't seem like a good thing. If after two passes the disk isn't quiet I try cleaning again or put it in the trouble stack. Check/clean heads after this. Also keep the finger on the load button and hit it if things sound too loud. I also have some PM procedures on my site which a company wrote for maintaining their drives. Search for RK05 http://www.pdp8.net/pdp8cgi/query_docs/query.pl David Gesswein http://www.pdp8.net/ -- Run an old computer with blinkenlights.