The seller should provide you with the details of these upgrades...assuming he knows. Appears
someone replaced the original can capacitor with an array of individual capacitors. The (2) large blue caps look to be dangerously close to the under side of the cover. The Gizmo on the back side I assume is a volume control. Above this are (4) wires laced through the cover holes..I have no idea what these are but it is something I would not recommend doing. PC board looks to be stock with a few modern components. The real value of this unit should be based on the transformers, chassis & cover assuming the transformers are good. As it is now with these modifications the value of this amplifier is greatly diminished. If it were me..I would not pay more than $200 to $250 for this unit.
Kevin @ Dynakit