BruceRPA
Addicted Member
I am working on a Marantz 2270 for a friend. It cleaned up very nicely, the amplifier sections adjusted perfectly and everything works for the first few minutes until there is a LOT of random noise through the left channel. I have isolated the problem to transistor #H408. The schematic shows that it is a "2SC493 Y or Gr". I searched for a couple of hours and can not find a replacement or a substitute that is not in a TO-3 case. The original is a TO220 case. I am really frustrated that I can not find a simple replacement for this thing. It doesn't look like anything all that unusual, at least to me. I did find an old comment in the archives of another forum about a similar model from our very own Echowars that stated that these transistors are troublesome and should be replaced as complimentary pairs (it's mate is a 2SC1000 Gr or BL). I am all for doing exactly that if only I could find the transistors to do so.
While we are at it, I am also working on a Technics SU-8600 for the same friend with exactly the same symptoms. In this case the trouble has been isolated to TR405, which is a 2SA794Q.
If anyone can point me in the right direction I sure would appreciate it!
While we are at it, I am also working on a Technics SU-8600 for the same friend with exactly the same symptoms. In this case the trouble has been isolated to TR405, which is a 2SA794Q.
If anyone can point me in the right direction I sure would appreciate it!