Viking Ranger II neutralization on 6 mtrs

[n4wc]

My Ranger II works very well on 160 thru 10.  It will sort of tune up on 6 but most of the time it oscillates and the grid current goes to ~5-7ma and the plate current might drop off to ~50-60ma, or go above 150ma.  When I move the FINAL adjust to ~98/99 from ~94(kinda where it is supposed to be), it is as if a switch is thrown and the above occurs.  If I keep the grid at 1.5ma and the plate to ~120 it seems to be more stable, but it won't stay very long, then back to oscillation.  Multiple tube swaps; 4 different 5763 and 6CL6 and 6146A. This xmtr is stock and has been cleaned and recapped, and 'reresistored' as necessary.  I found one cracked solder joint at the top of the plate choke, but fixing that didn't help.
Thanks for any insight into this opportunity.

Bill