[R-390] Need help -- direct me to 6BE6 product det mod info

[Phil M.]

I've just acquired a Collins manufactured R-390A that someone has supposedly
installed a product detector mod that involves replacing the 6BA6 BFO tube 
with
a 6BE6.  I seem to remember reading an article about this mod in some 
magazine, perhaps an Electric Radio article.  I would appreciate it if 
someone could point me
toward a reference.  I am not concerned with reversing the bfo tube socket 
mods as they should be obvious but I do have a disconnected and possibly 
jumpered pin on a plug in the wiring harness and would like more info before 
trying to set this
straight.

thanks, 73,
Phil
W5BVB