Vintage Synth Repair

Mark;
Have you had the Hammond A amplified prior to this time?
 
It is possible the 31H needs to have its filter and coupling caps
replaced.
 
It is also possible there is a poor ground connection between the organ
and Leslie.
 
Mike
 
 
<snip>
 
I recently bought a 31h and when I attached it to my model A discovered 
there was a rather loud hum comming from the bass rotor. After it has 
been on for a few minutes, the hum get much quieter, but dosen't go 
away. Anyone have an idea that I can try. Thanks.    Mark.