Harman Kardon 630 Humm/Buzz

[OskarBas1]

My 640 is making a kinda anoying Humm/Buzz sound. When i experienced the same thing with my 330B i replaced the 2SC458 transistors with great results. So I'm wondering if there is any similar transistor in the 630 known for making these kind of noices and In that case what should I replace it with? If not, what can be the cause of my the sound? Thanks!

 

[dlucy]

Best path is to look through the 630 schematics and compare those transistors to the ones in Top Ten Worst Transistors - noisy, failure-prone, whatever... and replacements