A couple of weeks ago my NAD C350 went into protection mode after a loud bang from the speakers.
On removing the cover, the main psu caps looked suspect so I took them out and measured them to be faulty. Had a job finding replacements of the exact physical size but settled on Chemicon 50V caps from Farnell USA which are the same size physically and rated at 63V peak so hopefully will be okay. Farnell part number is 1363659.
After replacing the caps the amp was still going into protection mode. First, I checked all the outputs from the psu board and found there was no 37V output.
This turned out to be safety resitor R402 blown. Replaced R402 with a wire link as recommended in other posts. Then found amp was still going into protection mode, with around 4V dc offset. R142 and R144 were smoking, so I checked all the nearby transistors. Found Q112 and Q114 were faulty, replaced these and all is working now!
Hopefully this will be of benefit to someone. Thanks to Bob Burbeck for pointing me in the right direction!
On removing the cover, the main psu caps looked suspect so I took them out and measured them to be faulty. Had a job finding replacements of the exact physical size but settled on Chemicon 50V caps from Farnell USA which are the same size physically and rated at 63V peak so hopefully will be okay. Farnell part number is 1363659.
After replacing the caps the amp was still going into protection mode. First, I checked all the outputs from the psu board and found there was no 37V output.
This turned out to be safety resitor R402 blown. Replaced R402 with a wire link as recommended in other posts. Then found amp was still going into protection mode, with around 4V dc offset. R142 and R144 were smoking, so I checked all the nearby transistors. Found Q112 and Q114 were faulty, replaced these and all is working now!
Hopefully this will be of benefit to someone. Thanks to Bob Burbeck for pointing me in the right direction!