I recently acquired an Ameritron AL-811H HF amp.
The tubes in it were in rough shape so I replaced all 4 of them with a
new set of Chinese tubes.
The best I can get is just over 400w carrier with 75w drive on most
bands. The HV reads about 1650V unkeyed and sags to about 1500V when
keyed. I read somewhere that the suppressor resistors can go high if
overheated, causing low output but I checked them and they all read very
close to 100 ohms as marked.
Are there any other known problems with these amps that can cause low
output ? I'm all ears to any other ideas before I go ripping it apart.
Tnx, Hugh VA3TO
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