Re: "Fuzzy" FM
You can align a ratio detector without a sig gen. The IF needs to be correctly aligned, and you need two voltmeters. Put one across the electrolytic, the other at the output. Tune to a strong signal. Adjust the ratio detector secondary for peak voltage across the electrolytic. Adjust the primary so the output is half the first figure. This assumes a typical unbalanced ratio detector. If balanced (i.e. the electrolytic does not connect to chassis) then tune for zero volts on the second meter instead of half.
Not perfect, but close enough.
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