Hi All,
I have a little Henry 1KD5 (single 3-500z) amp and I think the tube is going
dead. I dont have a lot of experience with 3-500Zs so bear with me here..
The tube has a 1982 date code so its an older Eimac. The amp has been
working fine for the last month (I use it every day for 3-4 hours), but the
output now will drop pretty fast when tuning. The odd thing is as the
output drops the input SWR goes up. It will level off then the power will
climb a bit. It will drop from about 850 watts to 600 in about 5 seconds,
and the input SWR climbs from 1:1 to 2:1 in that same time period (even with
a tuner on between the radio and amp the output power still drops the same
amount with a constant 1:1 SWR). The HV and grid current does not change
but the plate current drops. It has been gradually getting worse and 10m
output is also down a bit from when I first started using it. I dont mind
buying a new tube but I hate to waste the $$ if this sounds like something
else is wrong. BTW, I replaced the filter caps when I first bought it...
73,
Kevin
KB9UPV
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