Uncle Peter wrote:


I had that happen with the filters in my NRD-515 JRC receiver.
Fortunately, it wasn't too difficult to open the filters up, which
allowed me to dissolve the old foam rubber
blanket that cushioned the mechanical filter elements. The
foam had to decayed to a chewing gum consistency and the
filter losses skyrocked. These were late 70s or early 80s
vintage IIRC. Regarding the patent issues, I don't recall
the particulars.

Pete k1zjh

Does the name Kokusai ring a bell? I used one in a hoimebrew set in the
mid-70s and it was a really good filter. But alas, I recall hearing
later that this was one of the brands that had the foam problem.

-Bill