[Winky Dink]

Intuitively, I had mistakenly thought that tightening would reduce the capacitance, but then I got down to determining the range of the tuner capacitors and trimmers.  Both trimmers were 0-25 pF.  The troublesome trimmer wasn’t defective, but it acted funny because it was fully tightened (max capacitance) at the conclusion of alignment.  Then I realized that the mysterious 7.5 pF cap under the chassis (not in the schematic) was parallel to the trimmer--to jack up the tuner capacitance a tad.  I replaced the 7.5pF cap with 20 pF, which put the total capacitance back into an adjustable range, and I got a good alignment.


So, everything is good EXCEPT that there’s an unacceptably loud buzz.  I have tried all previous suggestions, although this is different from the original hum.  I switched out all the tubes except the 14B6.  I tried moving the radio to a different room.  And of course I’ve been over the circuitry numerous times looking for errors, shorts, bad connections, etc.  
 Here’s a 15-second listen:

https://picasaweb.google.com/lh/photo/Uf...directlink

The only variation from the schematic are that the electrolytics are 33-22-22 uF instead of 30-25-20.  The buzz starts instantly when the set is turned on, and once the tubes are warmed up it increases with the volume.  The only thing that reduces the noise is taking off my hearing aids.

I’m hoping that an experienced person can give me some direction for determining the origin of the noise.