Open (intermittent) grid resistors. Very common on SB-200s They are 33
Ohm.
73
Jim W7RY
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
On Behalf Of Bob Green
Sent: Thursday, September 28, 2006 10:15 PM
To: amps@contesting.com
Subject: [Amps] Newbie Question II
Hi again, everybody --
Thanks to all who answered. Now if I can just get my hands on the amp,
I'll
give them a try (The current owner just left town for 2 weeks).
Here is another problem for all the gurus out there. I also have a
SB-200
with most of the Harbach mods.(HVPS, Soft Start, Soft Key) It also has
AG6K's Parasitic suppressor. Whenever I key it using my 756PRO in RTTY
mode, the output power is VERY LOW (50-80 watts or so). Plate current
for
both tubes is running about 200-250 ma, and grid current pegs
negatively.
The tube plates turn a brilliant red-orange, and the heat above the tube
compartment goes WAY UP. Every now and then, the power out jumps to 700
or
so watts, but only for a second or two. The plates don't have time to
cool
off before the problem comes right back.
I have new Taylor 572B tubes (still in the box, in case I need them).
What could be causing this problem? Would a shorted or open blocking cap
or
a tune or load control do this? I suspect the solution to this problem
is
easy, but so far it has eluded me.
Only a week or so to the CA QSO Party. I'd sure like to use it then. . .
Any
ideas, anybody???
73,
Bob Green W6BBL
w6bbl@charter.net
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