[Heathkit] SB-1000

[Charles W BWW Burkhardt]

First let me thank all who responded to my request for help in
establishing the tube bias for the 3-500z and replacing the 0.6 ohm
resister for the plate current metering circuit. I found two 1.2 ohm, 1%
resistors for the meter and used 10 3 amp 1000V diodes to replace the
Zener. Both of these changes seem to work well. Plate current responds
and the grid current is within bounds.
   I am now back to the  original difficulty, which caused all the
problems. When I use a moderate amount of plate current-about 100 ma- and
low grid current of about 80 ma, the tube plate glow red. MOderate
amounts of power, say 150 watts, cause the  plate to turn orange with cw
keying. If I send too long (into the dummy load)sd0 I blow a fuse. Bad
tube? Any ideas will be appreciated. Thanks, Charlie, K0GPF