[R-390] Filters

[quartz55]

I could see someone making a DSP setup to replace the filter 'can'.  Not me though.  It would be nice to incorporate the front panel dial with an encoder so it could have variable bandwidth from .1 to 16KHz, just like original only continuous.  I think that would sell if the price could be down around $200.  I'd buy one, especially if I can't get the old filters working.

I'm assuming my coil windings are good since I'm measuring 50 ohms in and out, it's just the resistance to ground that seems wrong, I'm hoping it's just a matter of cleaning them up and re-assembly.  I may start pulling the 4K apart today.

Again, do I have to drill a hole in one of the end caps to keep from blowing the thing apart while heating the end?  I'm going to wrap a wet towel around the label to see if I can save it and take off the input end (bottom) first.

Also, is the ground lug on the end cap just soldered on, or can I use that to pull with and what is this nubbin in the center of the bottom end?
http://i251.photobucket.com/albums/gg287/DogTi/R390A/filterbottom_zpse5ba0910.jpg