[Racal] Ra6790 repairs

[tfrobase]

I have had an intermittent problem with my 6790 for a while.  Poor sync and
a lot of noise on anything that required cw including SSB and then last week
the tuning encoder quit.

I found a bad LM339 in the encoder circuit, took the front panel apart
replaced the chip, put all back together and it still didn't work.  Tore it
apart again and then I triggered the scope from the encoder buffer to the
processor buss and found the cmos buffer was also bad.  Once I had that
fixed my intermittent problem kicked it, I found it was a noisy pot on the
723 regulator on the A7 board, go figure.  Back in the console working like
a champ.  Food for though for others ... 73, tom N3LLL



Thomas L. Frobase
League City Texas 77573