Kale
Super Member
I've been away for a long time with restorations on Sansuies, So here it is one what is still in progress ...
Sansui Aplifier AU-D9. Sorry what I dont have a picture on which you will see how it was looking when I got it, but I have lot of other interesting picture what I took during my restoration job on that nice amplifier.
But right at the beginning this thing was suspicious to me:
This yellow wire was in the air (not connected)!! And uninsulated too!!!
In that moment I knew it will be one interesting restoration….
That yellow wire is one “sensor” for protection circuit, so maybe this amplifier was in protection mode all time, and previous technician fixed this with disconnection of this wire!
Another interesting thing what I have noticed is this:
I really dont know why previous technician replaced those two 2sa992 small signal transistors in Diamond-Differential circuit with totally inadequate those TO220 transistors. Because of that you cannot adjust DC Offset to close to zero voltage. I replaced all transistors in complete Diamond-Differential circuit with matched 2SA992 2SC1845 transistors. You see that previous technician changed all carbon film resistors in that circuit with metal film resistors…. it is good but if you asking me, unnecessary.
Plus, the same technician damaged printed circuits during dismounting those transistors…
Sansui Aplifier AU-D9. Sorry what I dont have a picture on which you will see how it was looking when I got it, but I have lot of other interesting picture what I took during my restoration job on that nice amplifier.
But right at the beginning this thing was suspicious to me:
This yellow wire was in the air (not connected)!! And uninsulated too!!!
In that moment I knew it will be one interesting restoration….
That yellow wire is one “sensor” for protection circuit, so maybe this amplifier was in protection mode all time, and previous technician fixed this with disconnection of this wire!
Another interesting thing what I have noticed is this:
I really dont know why previous technician replaced those two 2sa992 small signal transistors in Diamond-Differential circuit with totally inadequate those TO220 transistors. Because of that you cannot adjust DC Offset to close to zero voltage. I replaced all transistors in complete Diamond-Differential circuit with matched 2SA992 2SC1845 transistors. You see that previous technician changed all carbon film resistors in that circuit with metal film resistors…. it is good but if you asking me, unnecessary.
Plus, the same technician damaged printed circuits during dismounting those transistors…