Hello everyone,
It looks like I have the same problem as Raymond, the original poster.
I went on holiday and when I got back my NAD C316BEE showed no sign of life at all. I have heard that there were heavy thunderstorms with lots of lightning while we were away. I was hoping that a fuse had blown somewhere, but there is no current to the only fuse, which is fine. I followed the current, which led me to the startup circuit board. And then I googled and here I am.
I measured diode D63 (P6KE200A) and it shows the same 31.6 ohms in both directions. D64 (UF4006) behaves the same. Only D65 (MUR120) seems to work as I, a computer scientist and layman, think it should (i.e. in this case no current in one direction, 0.7 volts in the other).
I can replace diode D63. My question: is it possible that diode D64 is also defective?
Thanks in advance for any advice.
Attila
It looks like I have the same problem as Raymond, the original poster.
I went on holiday and when I got back my NAD C316BEE showed no sign of life at all. I have heard that there were heavy thunderstorms with lots of lightning while we were away. I was hoping that a fuse had blown somewhere, but there is no current to the only fuse, which is fine. I followed the current, which led me to the startup circuit board. And then I googled and here I am.
I measured diode D63 (P6KE200A) and it shows the same 31.6 ohms in both directions. D64 (UF4006) behaves the same. Only D65 (MUR120) seems to work as I, a computer scientist and layman, think it should (i.e. in this case no current in one direction, 0.7 volts in the other).
I can replace diode D63. My question: is it possible that diode D64 is also defective?
Thanks in advance for any advice.
Attila
Dear Agorog,
In my case ( my NAD C316BEE which refused to be "ON" ) it was diode D63 ( P6KE200A ) that had to be changed.
Being a little lost, because I did not have its Power schematic in order to understand...
I also changed :
- IC62 ( TNY274P ),
- D65 ( MUR120 )
- and IC63 ( TL431 ).
But it was not at all necessary !
Raymond
In my case ( my NAD C316BEE which refused to be "ON" ) it was diode D63 ( P6KE200A ) that had to be changed.
Being a little lost, because I did not have its Power schematic in order to understand...
I also changed :
- IC62 ( TNY274P ),
- D65 ( MUR120 )
- and IC63 ( TL431 ).
But it was not at all necessary !
Raymond
Dear Raymond,
Thank You for the fast reply. I will be replacing D63 when the replacement arrives, but I fear that in my case D64 may also be faulty. I am not sure how to test it better: I used a multimeter with the "diode" setting for the test and it showed the same low value in both directions for both D63 and D64.
Thank You for the fast reply. I will be replacing D63 when the replacement arrives, but I fear that in my case D64 may also be faulty. I am not sure how to test it better: I used a multimeter with the "diode" setting for the test and it showed the same low value in both directions for both D63 and D64.
I finally managed to replace the D63. I first tried to remove it on Saturday. The heat loss through the diode was so high that I failed. Today I cut the diode in half and managed to remove it very easily. Anyway, my amp is working again! YES! Thanks Raymond, thanks Audio Service and the people at diyaudio.com. Next time - when a heavy storm is approaching - I will unplug the amp 
Just wanted to thank all of you sharing your experience and diagrams, which made it possible for me to repair my NAD C316BEE V2 on my own.
It also had the issue that it did not turn on and only made a clicking noise.
After replacing the D63 diode it does work again.
Measuring the diode also gave results in both directions in diode test mode of my multimeter.
Thanks, Thomas
It also had the issue that it did not turn on and only made a clicking noise.
After replacing the D63 diode it does work again.
Measuring the diode also gave results in both directions in diode test mode of my multimeter.
Thanks, Thomas