09-11-2013, 11:35 PM
I've done literally hundreds of AM (even some FM) alignments by ear, before I finally could afford a scope and signal generator. The primary thing is that one has to assume that the IF's are at least close (a few KC either way isn't super critical). From there, I found a weak station and moved the adjustments just a tiny bit to see if there was an improvement. If there was, I would tweak each stage for max volume. Then I would go back to the tuner, find a weak station around 1400-1500, and adjust the antenna trimmer and the oscillator till I had the station in the proper spot on the dial with maximum volume. Usually, they turned out much more sensitive and selective. It's surprising that even if a stage isn't tuned to the exact frequency in the specs, performance can be significantly improved by simply tuning to all the SAME frequency (IF's).