Ira,
Sounds like you need to replace the electrolytic capacitors.That sound is commonly called motor boating. The schematic for the model 16L shows them to be 8 mfd. Go ahead and replace the others while you are at it. The schematic does not show 6A3's on this set and I don't think they would be a suitable substitution for the correct ones. you can pull up the schematic under the resources section and pay attention to the "changes" pages and determine which "code" yours is-this is a reference to a particular production run on this model that identifies changes that were made.There should be a code number on the label that identifies the model number. good luch-this is a nice set.
Jon.
If Jon's suggestion of replacing the filter caps doesn't fix it, you should go ahead and replace the other caps.
If you have limited use of your hands, you may need to get some help. I supposedly have complete use of my hands, and still struggle to pull some radio chassis and to replace caps.
There are a few different things that can cause motorboating, which is a low-frequency oscillation. For example, a capacitor may charge up until it or some other component leaks or discharges - causing a audible "putt." Then the same thing is repeated.
Doug
:I hope someone can steer me in the direction to get it going and pray it isn't the transformer.