OK, now that I've bragged about my amp's performance I have a problem
with my 4-1000A!
Tonight I turned the amp on to work some DX and when I applied the high
voltage, I got all sort of blue glowing and sparking inside the tube. In
fact it was inside the plate structure. I believe that one would call
this a gassy tube. The tube draws about 400 mA plate current without
being keyed and the grid current is switching between 0 and 250 mA as the
internal sparking occurs. At one point I drew over an amp of plate
current. Since it's all inside the plate structure, I am assuming that I
have a tube that has developed a SERIOUS case of gas. And no, I don't
think it is parasitics although some may claim this!
The last time I used the amp was exactly 2 weeks ago. Everything was
working fine. It has been sitting idle for the last 2 weeks as I have
been traveling and w/o time to play radio. All my HF antennas have been
disconnected at the entrance to the shack, so it hasn't taken a lighting
strike unless the strike came through the 110 or 240 Volt lines, but all
my other equipment works fine. The HV power supply works fine when I
disconnect it from the tube.
Is this tube gassy? Is there a way to fix it? I am trying baking it
right now with just the filaments. So far it hasn't helped. Should I
pop in a new tube?
Thanks in advance.
Guess I should keep my mouth shut about performance. Why does Mr. Murphy
like me so much!
:-)
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na <--- CHECK IT OUT! It's been updated!!!!!
"A life lived in fear is a life half lived."
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|