[Boatanchors] Eico 720- 40 Meter Parasitic

[David Stinson]

Working on an old Eico 720 "novice" transmitter for a 
friend and it's got me pulling what's left of my hair out.
It has a parasitic oscillation in the Buffer (6AQ5) only 
on 40 meters.  Works OK on other bands.
With the rig in "TUNE" and key-up, no xtal, the stage
oscillates in the high 6 MHZ area.  Tuneable by watching
the grid current meter for freq and amplitude 
with the GRID TUNING control.  GRID DRIVE,
which adjust the screen voltage on the stage,
controls amplitude. PA Plate circuit has no 
effect on the oscillation.  
I've subbed across all the bypasses.  
Resistance to ground in the stage is normal.

Has anyone seen this in an Eico 720?