Stumped by my WG 6101

Hi All,
  I have a WG 6101 (Tempest) monitor in an old Omega Race cabinet that I
use for my Atari multi-vector setup. Basically I have completely
re-wired it with all Atari stuff at this point.
   Anyway, the problem that I have had for about 6 months now is that I
have "noise" in my vectors. It is in both the X and Y axis and seems to
be high frequency since I can see the noise repeat in a nice long
horizontal line about every inch or two. Here is what I have done.
  -Replaced my Switching power supply with the old REG/AUD II setup
  -Main +5V filter cap is good
  -Replaced all caps in monitor with above or equal values.
  -Isolated power supply harness from XY and RGB harness
  -Checked all grounds for loops and/or breaks
  -Stretched game PCB 5 feet away from monitor to see if the monitor was
        sending RFI onto the game PCB
  -looking at the X and Y outputs there is noise on them leaving the
        game PCB, but if I disconnect the monitor the noise disappears.
  -my HV unit sometimes howls at an audible "annoying tone", this is
intermittent though and
        does not effect the noise in the pic at all. Disconnecting the HV unit
definitely
        takes care of the "tone".
  -rechecked all solder connection and cap polarities on the HV unit,
all caps are above or equal
        in capacitance.
 
Okay, that is what I have done so far. Im really getting distressed
after all this time. I really cannot
figure out what it could be. I don't have a spare 6101 around to try out
to see what happens either. I have swapped game PCB's too with no help
at all, same problems. I added 1000uf caps to the +/-15V supplies to
see if that would take care of the noise but no such luck. The main
filter caps on the deflection board are from an old electrohome B/W with
the values of 6800uf (they are still at 6800 uf, but I only have a
capacitance meter) instead of the regular 4700uf. I figure that it has
to be in the monitor somewhere since when I disconnect the main plug the
noisy XY lines disappear but I really cannot fathom how something like
the 15KHz is getting into the power supply with all the caps being okay.
Ohh... leaving the monitor plugged in but disconnecting the HV unit
leaves the XY signals clean and "noiseless", only when the HV unit is
connected do the X/Y signals get noisy coming out of the game PCB. The
problem "does" get worse with time (after 10 minutes or so) which also
seems like a cap problem. Could a bad HV transformer be causing this??
Maybe those 6800uf caps??
  HEELLLPPPPP!!
     jess

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