[Hallicrafters] Help with SX-101 Mark III

[Markus Thomerson]

Hello to the list.
I just obtained a very nice SX-101 Mark III and I need some advice.  The BFO
has an intermittent instability.  I can be listening to a CW (or SSB for
that matter) signal and the BFO will start to warble and then take off,
sometimes up in frequency and sometimes down and then it usually returns to
normal.  It doesn't matter how long the radio has been on.  Any ideas and/or
pitfalls would be appreciated.  I am just beginning to learn how to work on
tube receivers and I apologize in advance for the bandwidth.  Thanks,
Markus.