Hi: I finally got this set up and running . Which answered some of the questions I asked here .At least to some extent .So I wanted to post what I learned from all of you and fiddling with this radio . I replaced the original discriminator with a mini miller 12-c45 455 khz discriminator.I could not find coil L21 which in the end I believe turns out to be a choke . It is not present in typical circuits found in a Meissiner build manual of the period. So I went without it .Seems to still work and not to badly .I did not go to the extent of measuring the oscillator shift when tuning . But when tuning a pushbutton station slightly off center freq it is easy to see the automatic tuning make a reasonable(and sucessful) attempt at correcting it ! Also stronger stations seem to stay locked in . So it works good enough to be happy with it and to pass that replacement info along to anyone else who may be faced with the choice of sticking a regular can in there . I still will look for an original replacement . When I take this one out I will measure both and compare then . Of course the original will be better.But this one is acceptable and a generic replacement for these type of circuits . Thanks again to all who helped me on this .I hope this might decreased the learning curve for someone out there!If not it's the thought that counts . Also this is a really nice radio . The fidelity controls work well and the sound is pretty good . Well built console and a easy to work on chassis.Even with the complex circuits this is a easy recap in my opinion. Thanks!
bill

The AVC working as you described is about all one could ask for. Doubt that the original part would perform much better. The AVC compensation range isn't that wide, so it's kind of a subtle feature anyway. It will work best on strong stations- weak ones don't generate enough error output to do anything noticeable.

One thing to look for is symmetry- does the AVC compensate equally when mis-tuned both high and low by the same amount? If not, this can be adjusted by twiddling the slug in the transformer that you replaced.

:The AVC working as you described is about all one could ask for. Doubt that the original part would perform much better. The AVC compensation range isn't that wide, so it's kind of a subtle feature anyway. It will work best on strong stations- weak ones don't generate enough error output to do anything noticeable.
:
:One thing to look for is symmetry- does the AVC compensate equally when mis-tuned both high and low by the same amount? If not, this can be adjusted by twiddling the slug in the transformer that you replaced.
:
CV: Station I tested with is pretty strong around 1400khz.Low stations do nothing perceptable as you
said .A little adjustment on the secondary could make
it better .But i would say it is ok both ways.The secondary adjustment on this replacement is up under through a hole in the bottom.So tough to get at .The original was on the side of the can up top. So you could do exactly as you suggested without much difficulty. I think what helped in this setup was a modulated i.f during alignment.Stromberg suggest visual alignment. But close enough for now . Thanks again for help on this . When I started I did'nt even know what a discriminator was . So I actually learned something this time!And it turned out easier than expected .It's nice to bring this thing back to life.
Way to nice to part out!
bill