Aside from the part numbers for the output transistors, does the schematic set seem to match your board? Those two sets of transistors are similar, and one set could be substituted for the other in this amp.
I have 400SC drawings for versions from 1998, 1999, 2001, 2005. They are all VERY similar.
Since your NPNs get hot immediately, your +60 is probably being loaded down to 50. Are your +16v rails OK?
Are you working with a load? get rid of any speaker load until the amp settles down.
Is there any DC offset on the affected channels?