[Hallicrafters] SX-42 Alignment

[Rich Soennichsen]

Very frustrated trying to align this thing....  I am following the
alignment procedure from Sams Photofact as I find the one in the
manual VERY confusing.  I have constructed the RMA dummy antenna.

I am able to peak the IF stages as per step 1.  Step two calls for
setting the mode to CW, inject 455 KHz and adjusting A7 (transformer
in BFO circuit for zero beat.  I get no beat at all.  Perhaps the BFO
is dead.   If so I have to skip all alignment steps in CW mode.

I suspect the crystal is dead so I have to skip the alignment steps
when the selectivity is set to a crystal setting.  (Can you replace
this crystal with a modern one?)

I performed the 10.7 Mc IF alignment, it went better except for the
last step, I cannot find these peaks off the minimum.  May have to
hook up the scope....

On to the RF section.  Did not get far.  Hooked up the RMA dummy load
and injected 1500 KHz into A1.  Adjusted A21 (RF cap) but I cannot
find a maximum that corresponds to my injected signal.  I find a
maximum but it is not MY signal.  In fact it appears to be an actual
broadcast signal.  I disconnect the generator, still there.  I shorted
both antenna inputs to ground, still there.  Since the volume is all
the way up I can actually hear the signal from the radio itself.  If I
tune the radio to look for MY signal I find it at a dial indication of
~800KHz.
The same sort of weirdness happens when I go to the next step and
adjust A22 (RF coil).

Frustrated, giving up for now.


73
Rich
W7SOE