[HAM] **SPAM(6.1)** M100 crackles as it warms up......any suggestions?

[kev conlon]

Hi All
..this one as it says on the tin!!
As the organ warms up..there is a 12 to 15 second period of
crackling..then everything OK.
 
Could this be a capacitor fault..or even a dry joint somewhere ..where
should I start looking??
 
Kev/UK