RK05 drive foam deterioration and replacement

--- Hi Carl, Just to add to Philipp's excellent advice: I replaced the foam in my RK05 with 1-inch high density foam from a JoAnn store: http://www.joann.com/airtex-foam-chairpads-1-high-density/prd23481/?green=C… Their warning not to cut with hot wire is not to be ignored! I found that cutting with an electric knife worked well. Used contact cement to glue it to the blower flange. Works great. There is about 3/4" clearance between card cage and blower, so it compresses appropriately. By the way, removal of the blower is a pill. The fasteners are buried deep and require a hex key driver that is much longer than ordinary ones. Found an inexpensive set at Home Depot, which did the job. One fastener is particularly hard to get to. I decided to replace the hex fasteners with ordinary screws and emphatically did not install the fourth one. Three work fine. Note that the Velcro strap which is used to tighten the absolute filter is laid under the blower mounting, to secure it. I used adhesive to keep it in place when the blower is removed. I notice that a lot of these drives seem to be missing the prefilter, as mine was. I used a common window screen kit to make the replacement filter. Used window screen on the outside but 100um nylon filter fabric from eBay, also tucked into the spline on the inside. Makes a decent facsimile of the original prefilter. You can buy new-old-stock replacement absolute filters here: http://www.varx.com/ I paid $60, plus shipping. A tip about getting the old filter out: I found it difficult to pull the filter off of the flange leading to the blower. Thinking that I must not be doing something right, I ended up pulling the blower off again to see what was happening. Finally decided that the old filter just had to be yanked off. Perhaps the plastic has stiffened with age. It finally came off. One thing that distracted me was the fact that, in spite of the flange blocking removal, the absolute filter fits the blower duct very loosely. Hence, a Velcro strap is provided to tighten the filter against the duct. Some might think all this attention to filtering is overkill but after seeing the illustration on p. 1-17 of the 1976 RK05 maintenance manual of the 100um head flying height versus various contaminants, I have been very careful about dust. It's a relief that Philipp has had not-so-bad experiences with head crashes but I would like to minimize the risks. Steve L. http://www.tronola.com/