[R-390] R-390A intermittent loss of Diode Load voltage

[David Wise]

My 1954 Motorola R-390A had a manufacturing weakness that may have been present in all IF modules.  The wire powering the screen grid of one of the pentodes has a sleeve of insulation and goes around the edge of a shield.  The shield wore through the insulation and the wire began to intermittently arc to ground.

Dave Wise
SWL in Hillsboro Oregon (inactive)