NAD 502+512+514 - Burned Transistor from Focus Power Buffer Output Stage (pos. Half)

[tiefbassuebertr]

This is to observe in general by all devices of the above mentioned models.

At least there must be resolder at solder side of the main board in this aera.
Better solution is the replace of this transistor to a version with TO-126 outline (e. g. BD139) and heatsink (or electrical isolated mounting on chassis).

Who knows the reason for the enhanced power loss in the upper half (positive rail) ?

BTW - The laser unit (optical pickup) is the KSS-210A from Sony.
And the Transistor is Q608 (2SD1858, ROHM-MPT3) by NAD514 and Q102 by NAD 502.