[Premium-Rx] Racal 6790/GM First Mixer Question

[Edward Knobloch]

Hello,

Does anyone have the schematic for the first mixer of the 6790/GM?
(It is in a sealed tin box on the A-2 card.)  I know that the box
contains four MOS FET transistors, but I would like to know
what's going on.  In the tech manual, the schematic for the A-2 card
merely shows a black box for the mixer, labled U1.

Thanks,
Ed Knobloch