[AMRadio] SX100 with added product detector

[CL in NC]

I picked up a SX100 MK1 not a MK1A, and found an extra tube that turned out to be a product detector, added in a spot directly under the notch pitch shaft at the front panel.  Did some looking around to see if there was an old ham mag article about this but nothing found yet.  It uses a 6BE6 and is nothing like the one in the SX101, but it does work.  The design uses a multi-grid converter tube like in the SX101, but not the same one or circuit components, and it does not follow anything in the ARRL Handbook from around 1962 on where they used triodes.  The tube socket the builder used is a bit unique too, it is ceramic, with the tube solder lugs actually sandwiched in the ceramic exiting out the sides, with a central metal pedestal.   Anybody ever remember someone writing about designing this and installing in the SX100 series receivers?

Charlie, W4MEC in NC