Sansui 4000 -1150 board corrosion

[Flhrich]

Hi,

Im in the process of recapping my first receiver, thanks to all the great info on this site. In cleaning and prepping the 1150 board I noticed that both 1150 board have the same type of corrosion on top of transistor TR805 (2SC708A), where the diode sits on top of the heat-sync.

Has anyone seen this?


Thanks in advance,

-Rich

 

[KingBubba]

My guess would be that what has happened is caused by dissimilar metals making contact and causing corrosion, Copper/Aluminum.