[Heathkit] Wobbly HR-10B's

[Tom NØJMY - AAR7FV]

I've got a number of HR-10B's around here that I thought I ought to get
fixed up.  Out of four units, only one seemed to have a good strong and
stable BFO.  All three of the others either didn't have enough
injection, or they hopped around making CW sound
like the old Maxwell House Percolator theme song, or both.  Is this a
common trait in old HR-10's?  Is there any mods or fixes out there other
than just plain old troubleshoot and repair?

73,
Tom