[Heath] AJ-53 or AJ-21 schematic?

[Morris]

I just acquired one of each of these high fidelity AM tuners and could use
some documentation.   Since they both appear to be quite similar, docs for
either would probably be sufficient.   
I have forged ahead, repairing a locked slug in an IF transformer in the
non-functional one and then with comparison to the working one for
alignment.   The IF frequency seemed to be non-standard around 460 KHz (yes,
I tried 455 KHz but it had problems) so I used that and the old tuner came
up FB.   The only question remaining is about what appears to be an
adjustable filter coil on the output stage.   I am assuming that it is for
blocking any residual IF frequency that might slip through detection and
beat with a recorder erase oscillator.
 
Thanks for the bandwidth,
 

Morris 

 
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