My primary amp is the HL-2200 which has worked well since I purchased it
from a swap net abt 6 years ago. Recently it blew a grid fuse when I turned
it on ( mode sw in the cw ,or low power, position). Examination of one
3-500Z showed the plate off center around the grid structure, no Ohm meter
short. Rx, banged tube into gloved left hand, jarred plate into position
rplcd fuse, all ok. A week later, whump, another fuse same tube. Found crack
in plate seal, rplcd tube, all ok except amp now hard to drive. Believe tube
was slowly going flat all along. This amp has never had the input Pi ckts
modified for my 706 so probably low on drive. Question: Why not bypass the
tuned input ckts and use an antenna tuner equipped transceiver ( 765 ).
Also 100 W will not drive 2, 3-500Z's in gg. Takes 120 W. So will turn up
765 output, and to prevent splatter from overdrive will use a adjustable
negative current limited voltage manually applied to the 765 ALC input
connector. Any comments as to why, or why not do this, I am 77 anyos on this
earth and have a nervous condition that makes me solder my fingers together
so mods to those little input coils is out.
Bob,w5pvr
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