[Collins] 51J4 and AC Power gremlin questions (long post)

[Chris Kepus]

Friday evening I finally hooked up and started using my 75S3 and 51J4.
Sadly, the beginning of my fun was interrupted by a very strange and
bewildering power problem that I am submitting to the group in the hopes
that someone has "been there" or "done that".  My shack wiring is two years
new, wired and inspected to code.  The power source for the circuit in
question is a 120V 20 Amp breaker followed by a 20 amp GFCI.  The GFCI
output feeds 7 duplex receptacles in the shack.  The circuit has been in use
over the past two years and has worked FB.

Friday evening this circuit was feeding my Collins receiver "power supply"
(a variac controlled isolation transformer) which in turn was providing
power (and "power on" switching) for my 75S3 and 51J4.  All was well.  It
was the first time in several years that the 51J4 was fired up.  It worked
great.  I did notice, however, that the 3 kc filter on the 51J noticeably
reduced the signal strength compared to the 6 kc filter (even more than the
1 kc filter).  I also noticed that if I switched in the crystal filter to
position 1, the signal strength increased on all the mechanical filter
positions.  Hmmmmmm.  Why is that?  I know filters have insertion losses but
I didn't think there was that much difference between the 3 kc and 6kc
filters.  Is this normal?  Why did switching in the crystal filter make such
a positive difference?

Saturday evening, I went back into the shack to resume my play with the
receivers.  I turned on the "power supply" but the pilot light didn't come
on and the receivers didn't light up.  Scratching my head, I checked the
power plug.  It was solidly in the receptacle.  I tested the GFCI and cycled
it.  It was OK.  I checked the 20 Amp breaker.  It was "ON" (normal) but I
cycled it anyway.  But the outlet my "power supply" was using was still
dead.  I checked for power on the circuit by plugging a lamp (with a known
good bulb) into each of the other 6 receptacles with the same result as with
the receivers.  No power/no light. 

I unplugged everything that was on this circuit and then performed two tests
on all the receptacles.  For the first test, I used a plug-in circuit tester
that tells you with a three light combination if you have wired the
receptacle correctly or if you have a problem.  All the receptacles tested
AOK.  More head scratching.  What the heck is going on?  For the second
test, I took my multimeter, checked all the receptacles and found 120V at
each receptacle.  I felt better.  Where there's power, there's light! I
plugged in the lamp and switched it on.  The light did not come on.

Now I am into very serious head scratching.  What the H--- is going on?
Determined to figure out what was going on, I moved to a set of side by side
duplex receptacles for yet another test.  I plugged in the circuit tester,
plugged in the lamp (turned off) and connected my multimeter to the third
outlet.  With the breaker "ON" and the lamp switched off, the circuit tester
showed AOK (wired correctly) and the multimeter showed 120 V.

I then switched the lamp on.  Rats! No light...again.  But the circuit
tester light pattern changed from AOK to a pattern that indicated the "Hot
and Ground wires are reversed", and the multimeter reading was now "zero
Volts"!  What???!!!  When I switch the light off, the circuit tester pattern
changed back to AOK and the multimeter showed 120V. !!  In the meantime, the
breaker did not trip.  I did bypass the GFCI but that had no effect. 

So in summary, when there is nothing plugged into this circuit, both the
circuit tester and the multimeter results on each of the receptacles are
positive.

The instant a load is connected (plugged in, turned on) the circuit tester
indicates the "Hot and Ground wires are reversed", and the multimeter
reading shows "zero Volts"!  This result is the same regardless of the
receptacle being used.

So gents, does anyone have an idea about what is going on with either the
51J4 or with my wiring gremlin?  

Please excuse the long post,
73,
Chris
W7JPG