[R-390] Hum

Gord Hayward [email protected]
Thu, 12 Feb 2004 08:10:52 -0500


I had a similar problem and as John mentioned, it was a filament to cathode
leak in the noise limiter.  The impedances in that stage are high so the 
leak was
small enough not to show up on my tube tester, but big enough to give lots
of hum.  Replacing the tube fixed the problem, but I only found it by 
substitution.

Cheers de Gord, VE3EOS

-- 

Gordon L. Hayward, Ph.D., P.Eng.,
Associate Professor, Biological Engineering,
School of Engineering, University of Guelph,
Guelph, Ontaro, N1G 2W1.