I picked up a Drake R7 this week. I upgraded the 1st mixer to an SRA-3MH and
changed the diodes in the 2nd mixer and the translater mixer to matched
1N5711 hot carrier diodes (I don't know why they used 1N4148s in the first
place).
Anyway, this is where the story gets sadder. When I replaced the DR7 control
board the LED display worked for about 20 minutes, and then it died. I can
still toggle up and down through the 500kHz steps so the synthesizer is
still working but I am not sure what controls the display. +5V seems to be
present at the different chips. I don't know if that display driver chip
took a dive.
Has anybody else had this type of problem?

Pete