[VHFcontesting] 3CX800 amp problem
Ralph Matheny K8RYU
mathenyr at marietta.edu
Mon Jan 11 15:29:50 EST 2016
Last summer I posted a request for some help with a 222 amp that
had driven me nuts...and I wanted to say thanks to the several who
sent lots of good info. I finally gave up and set the thing aside
cold weather, when I found the trouble.
What was the problem???
Well, it wasn't the grid bypassing....it was the BNC relay that
was supposed to close when the amp was on. The contact was just
almost closed, giving me a little drive but the cathode circuit of
the 3CX800 would not tune....replaced the relay and all is well.
BTW...the grid ring. I used a EF Johnson screen bypass ring I had
left from a 1970's 2M amp. I soldered short pieces of wire from
each of the contacts to the flange of the ring and it seems to work
perfectly. I have no signs of grid ring problems...good output and
no instability noted so far. I don't know if that was luck or engineering!
More information about the VHFcontesting