Small lighting unit and this powered speaker shared cheap and nasty plastic
multiway mains adaptor. Much crackles and bangs from bad contacts in the
adaptor but both survived working order . This amp had smoke coming from it,
at the time of the crackling. The bridge rectified 52-0-52V ac supply used
to have a cap across it, burnt up to just 2 pins now.
Only FBT schema, out there found, is for the MAX 9SA for which that
component is 100nF 200V , so replace with disc ceramic of that rating or
higher? or C +R ? and of course advice to obtain metal cased mains multiple
adaptor.