Hi, I certainly appreciate everyones help with my strange problem. A special thanks to my friends Glen, Rodger, Mike and Jim.
Many worthwhile suggestions have been received, I'll list them in the order I feel are suspect.
Yes, the rig has 6146W tubes. All 5 are 6146W - modulators and RF outputs - my main suspect of the oscillation problem..........
A previous owner appears to have replaced all the tubes at some point, maybe trying to fix something, but has caused more trouble I think. Every tube  looks very new. Since I don't have 3 -  6146A to swap out, I'll have to get clever and yank the A's out of my SB102, only a pair, but maybe enough to see if it is in fact a problem with the W's. Yes, I remember when working for Heathkit during the 70's, it was frowned on to swap out to "B's".....in fact we only stocked the Heath part number tube instead of the RCA "B". 
A problem with the driver oscillating on a very low frequency, I'll try the 500 ohm resistor in series with the grid choke. The R64 56 ohm in the final screen ckts was missing from my rig, I've added that already per Johnson update sheet with no effect.
I'll check the "turnstyle" loading capacitor, I'm not sure about this, but I'll give it a look. 
The VFO may be giving me trouble,  straight through on 160, doubled to 80 I understand. I have all the shields in place with new lockwashers and nuts....so nothing loose here. The problem is the worst on 160, fading off as we go up to 80, then 40 etc. I'll scope the VFO to check. 
Will check the plate choke and caps....they look visually ok. 
New question, I see that the previous owner installed 2 150 V regulators in the Mod screen ckts, instead of the 2 105 V ones....why would someone do this? He also installed the wrong reg in the VFO, causing it not to clamp off with the keying adjustment pot...works FB now with the proper 0A2 instead of the wrong 0B2.
Very interesting, but frustrating none the less....I'll get 'r workin'
Bruce WA3MKC

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