hifi engine

NAD 712 receiver schematic


My beloved NAD just went totally dark. Act's like a blown mains fuse or power supply failure. Anyone happen to have a schematic handy. Or better yet already delt with this falure before and can advise.

Thanks in advance,

Could be a defective

Could be a defective power-transformer internal thermal fuse.
On transformer T1 it is between the BLACK and the WHITE leads (Points P4 & P17)
Disconnect them and check for continuity.
On T2 it is the BLUE and BLOWN wires (Points P5 & P9)

Other causes are bad solderings around power-supply transistors Q507 & Q508 and all 3-terminal IC power-regulators (IC501, 502, 503)
The IC's are also known to become defective as are Q507/Q508)

I've uploaded the full service-manual to here.
It should appear soon.



nad 712

Thanks for the info. Sure to be a great help!