Using sweep with the crystal at 60hz is not going to work. Too bad,
because it would be nice to see the pass band shape... I'll have to
check to see if my old sweep generator will take an external input
down at 10hz or lower, but then I don't know how I would sync to my
scope sweep.

The phasing control does have -5 to +5 and there are no stops. 2
sources don't mention where to set it during this alignment and the
third says half meshed and to set the knob to make that zero. It says
to leave it there for the rest of the alignment steps, which includes
peaking the whole IF section to match the crystal, which to me means
1/2 meshed should be on the peak and the null should be off to one
side (either frequency or phase control setting-wise).

I didn't have much luck with AGC voltage, perhaps I was latching on at
the wrong place. I tried the plate of the AGC rectifier and also
downstream of a resistor off the cathode. Didn't see any real swing
with generator frequency anywhere. Perhaps my inexperience really
shows here.

So, resorting back to speaker output voltage, I decided to try using
AM from the signal generator with the BFO off. Low and behold, I now
clearly hear and see (on the meter) the twins peaks and intervening
null. I just can't seem to discern them using the BFO as recommended
in all the tech sources. Wonder what I am doing wrong, or why AM
wouldn't be a good way to do this anyway? One thing is that I am
injecting post 2nd converter instead of at the tuning stator. Maybe
the BFO would work better as per instructions if I injected at the
stator as per instructions. I noticed that when injecting at the RF
point, slight movements of the tuning knobs changed the peaking
frequency, so I just thought why not inject straight into the IF
section. Am I missing some kind of additional alignment by so doing?

Anyway, using AM generator injection into the IF section I now can
tune to the null and hold it pretty steady. I noticed slight tapping
on the crystal bounced the null around, so I opened it up and wiped it
off and retorqued it. Didn't seem to change anything, so mechanical
feedback must be inherent in these beasts. Back to that slug on the IF
secondary feeding the crystal filter... the swing between peaks and
null is so vast that on the HP400 I am using they are several scale
settings apart. Makes it hard to tune for maximum swing between
rocking the generator, switching scales, and turning the slug. Is that
for sure what the slug does (maximize the db drop from peak to null)?
Or is it to tune the IF around some certain position of the phasing
control? I was noticing when switching the filter in and out that I
can tune the slug to where the peak without filter is the null when
the filter is switched in (with phasing 1/2 meshed and set to zero)...
is this possibly what I am trying to accomplish or is this just
coincidience?

Sorry to be such a nuisance, but I have searched all over the web and
this topic has not been clearly covered anywhere I could find. It
seems worthwhile to reach some kind of understanding as to just how to
align these crystal IF filters. All your feedback so far is really
helping, but I am someone that really wants to understand what the
heck I am doing, and I am not quite there yet. Perhaps this is a great
understatement.

Dan