I have a Yeasu 2100B amp that has a problem on 40 meters. The load control is
at the end of the range on 40 and I am experiencing lower output than the other
bands with the same drive and plate current. The amp is new to me and I expect
the lower loading is related to using Svetlana 572Bs. These tubes are fairly
new and came with the amp. However, 80,20,15,10 react as I would expect as to
output and plate current. All voltages are fine and the mod to increase
cutoff voltage for the Svetlana has been done. The band switches look fine and
the plate tuning is correct and in the ranges you would expect as per Yeasu.
In all other aspects the amp works fine. I have had a parasitic event recently
that resulted in burned resistors and a shorted grid bypass cap. The load
issue predated the EVENT. Anyone seen anything like this related to Svetlana
tubes or the 2100B???
Larry
WB9YAJ
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