Please help with NAD 1020 Pre-amp

[zoranaudio]

Originally posted by lineup


Are these the same 47uF caps as C524, C523 in my posted schematic?

Well it's difficult to say without original schematic which I don't have too.
But, I think no, because if C533 and C531 was for the purpose and place where is signed red in your posted schematic than this caps should be the same voltage and for that purpose" for the feedback" usually is no more than 10 volts., and i wrote in my paper that c533 and c531 47 micro farads both but 35 & 63 volts so I am guessing that this caps are in other place , not the place you marked..
Unfortunately I loose the JPG images taken from the original NAD1020B, , what I found in my pc is just scanned PCB,s from this, and all components values is wrote on the paper by hand.
Perhaps I can open my cloned pre-amp to see what caps are 2 inches behind the treble potentiometer.
I opened so many times and i modified this pre-amp so now i maded "source Direct" option taken from other models of NAD which have this option, cos originaly 1020B does not have "source direct, or tone defeat" how you like it is the same.

Yepp!!!
in the meantime when uploading this image I found my old papers and found there that this C533, minus pole connected to anode of D505 and R550, so this caps is for the mute option perhaps and C531, but now this is not important.
Line up I also found the same purpose caps you red marked in this NAD1020B that caps are C525 &C526.

So now I hope everything is clear, and John again I hope I helped you, because the values of the caps I gave you is 100 % true.
But all will be more clear if we can find electrical schematic or complete servise manual, till now i didn't find , but have my papers with pcb and values of the components.
Good luck.

[pureh2o]

Grrreat! I really appreciate it guys. I can go forward now. 73s, and thanks again for all the help. John.

[zoranaudio]

Great dear John.
Now we can trust more cos both are HAM radio operators.
I wonder what's your call sign? we can made a QSO I am QRV mostly on 14MHz both CW ans SSB.
DIY spirit is 90 % in HAM radio operators, we know that very well as we see a lot of HAM's electronic designs.
GL & 73's de Z37HWX