View Single Post
  #2   Report Post  
Old January 27th 06, 08:36 AM posted to rec.radio.shortwave
Telamon
 
Posts: n/a
Default R7 display has died

In article ,
"Pete KE9OA" wrote:

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?


Another problem is that you replaced a 500 mW diode with a 250 mW diode
so have you checked to see if they are still good? Maybe they shorted
and took out a bias supply that is also used for other things like a
logic signal control voltage.

--
Telamon
Ventura, California