[gellenb]

I have an 87 that I rebuilt several years ago that worked great.  Never aligned it as the reception was very good. However, one day when it was on I heard some loud popping noises.  At first thought it was electrical interference since it was still playing.  After a few minutes, the popping suddenly got louder and more constant, the music died.  When up to find an 80 tube pinkish/purple with fireworks inside the tube.  So replaced the 80 as it was showing shorts.  Reception now very poor.  Found and replaced two bad 26's and the 27.  Helped but not much.  Went over the radio again, all caps & resistors, tubes showing good, good voltages.  I've decided to check the alignment now to see where that is.  Following the document here on philcoradio, "Neutralization of Philco Neutrodyne-Plus Receivers" I've been able to improve reception, but not to where it was in the past.  In that document, it has the following statement:

              >>> Adjust the 3rd neutralization condenser (number 6 in Figure 2) for minimum signal.    <<<

What exactly is minimum signal?   If by meter, is this when it's at '0'?  If by listening to the speaker, when the signal generator tone is no longer heard?  The process has improved reception, but not close to where I think it should be at this point, and I'm thinking my interpretation of minimum signal may be incorrect. 

Any thoughts on this or something I may be missing, please let me know.  Thanks!