Hello.
Need help.
Amplifier YAMAHA A-S300.
The power transformer is dead.
Primare is shorted.
Fuse F1 blown.
Please help me if a can to adapt the transformer of NAD C315 for Yamaha.
Original Yamaha transformer is very expensive for this old Amplifier.
Thanks
SM YAMAHA.
https://elektrotanya.com/yamaha_a-s500_a-s300.pdf/download.html
SM NAD
https://www.manualslib.com/manual/1186901/Nad-C-315bee.html
Need help.
Amplifier YAMAHA A-S300.
The power transformer is dead.
Primare is shorted.
Fuse F1 blown.
Please help me if a can to adapt the transformer of NAD C315 for Yamaha.
Original Yamaha transformer is very expensive for this old Amplifier.
Thanks
SM YAMAHA.
https://elektrotanya.com/yamaha_a-s500_a-s300.pdf/download.html
SM NAD
https://www.manualslib.com/manual/1186901/Nad-C-315bee.html
Read this and similar threads.
Substitutes are available from reputed sources.
https://www.diyaudio.com/community/threads/yamaha-cx-800-transformer.387135/latest
Substitutes are available from reputed sources.
https://www.diyaudio.com/community/threads/yamaha-cx-800-transformer.387135/latest
The idea is that transformers of the same specifications are available, no need for original Yamaha part.
And at a very attractive price.
And at a very attractive price.
just rewind the primary ,is normal find a lab near you
btw if burn maybe diode /caps need a look
Now he says secondary dead.
That requires investigation.
Primary open is an easier fix.
Yamaha...needs careful work.
That requires investigation.
Primary open is an easier fix.
Yamaha...needs careful work.
Isn't there a thermal fuse on the primary? Some of them have a small hatch in the bobbin that hides it.
Figge
Figge
Schematic shows thermal fuse on primary. A Blown/open thermal fuse would not cause other
downstream fuses to blow.
Amp is probably in standby/protect so main transformer may not be energised. You probably
have a failed power supply, blown outputs or... Refer to the self diagnostic mode in the service
manual.
downstream fuses to blow.
Amp is probably in standby/protect so main transformer may not be energised. You probably
have a failed power supply, blown outputs or... Refer to the self diagnostic mode in the service
manual.
Does the power transformer primary show continuity? If so, replace fuse, disconnect CB104, connect the device via a mains bulb tester and power it. Does the bulb return to and stay dim?
Best regards!
Best regards!
Finally transformer is good.
All voltages are correct.
I removed it from the amplifier and connected 230 volts to the primary winding.
Self diagnostic shows power supply problem.
Blink 2 times
All voltages are correct.
I removed it from the amplifier and connected 230 volts to the primary winding.
Self diagnostic shows power supply problem.
Blink 2 times
Last edited:
Probably failed voltage regulator +/-5V, +/-12V, or,,, If they are ok then check electrolytic caps on these rails.
So first up measure all regulated voltages against the service manual.
So first up measure all regulated voltages against the service manual.
Check for charred/discoloured resistors around the power supply and voltage regulators also any signs of stressed capacitors (unlikely in a "new" item). Possibly a short to GND, you could try diode testing each regulator looking for a short????