[K7Sparky]

Strange that both XXL are bad. Mine are original and the weaker one got put in the OSC. Might question your tube tester.

XXL is the same as 7A4

Mine 41-280 was also quit deaf. Someone had soldered the free end of the coupling stub to the padder (trimmer) on the left side of the tuning cap and that kills or sharply reduces the OSC.

Also note that Part 21 / 21A dual mica is only used when using the push buttons.

I ended up with a tiny artist brush and Deoxit on the band switch, upper / lower contacts on the push buttons and non-Loctak tube socket pins. One of the threads recommends one of those little dental brushes for the non-Loctal sockets.

Look on http://www.philcoradio.com/tech/schema.htm for the link to http://audiophool.com/Philco.html for Philco service bulletins and other resources