Its close I believe, the AQ20 just not on a daughter board, and this one is a class A/B. Outputs are BJT's in this one and not FET's
It appears that the problem is in the power supply, voltage, thermal... This one would be good to learn to markup a diagram in PDF Exchange Editor (or whatever you want to use). It will take 30 minutes or so to learn to use the editing tools but you only have to do it once then you will have the skill to use in other repairs.