NAD C325BEE Will not power.

[Kim Christensen]

Kim Christensen thank you for all your helpful advice!!! I certainly would not have managed to repair this if it wasn't for your excellent help! 

You're welcome. It was a fun exercise for me as well. Good to hear that all is working now. 

[paul_g_787]

Indeed! I do love a challenge and it is good to have some expert help as well!

I learned a lot more than I knew before about how amplifiers actually work from this one. It was good fun! 😁

[Per Hansson]

I would replace the SMD caps on the other module too, if you re-read my post #40 you will see they where bad on both.

[paul_g_787]

I would replace the SMD caps on the other module too, if you re-read my post #40 you will see they where bad on both.

I checked the ESR on them both in circuit and they were 0.3Ω and 0.7Ω (I forget which was which). Which I didn't actually do on the other module.
I didn't want to tempt fate and remove the module if I didn't need to just in case I made it worse! I had a very hard time soldering those SMD parts as it is!

[jhjove]

New to the forum (typically on diyaudio and audiokarma) and 2+ months late to this topic. Quite a nice dialogue and repair.

FWIW, I went through an almost exact repair sequence in February 2021. I acquired a C325BEE (a for-parts-only special) from ebay.
Although in addition to the +/-18V power supply issues, the main power board was fried on my amp. In the end I have a very nice working amp.

I wanted to add that the failed SMD caps on the CB21 + CB22 riser boards I replaced with similar SMD form-factor parts, but solid-polymer type electrolytics.

Again, I enjoyed the thread, very good info.

[FIXITNOW2003]

not seen a 325 but have seen some 320 versions these do suffer with poor elec caps  in the protection circuit. and output stages i would check the to see if esr is poor

[Mathijs]

Now 2 years later (february 2024) I am experiencing a similar problem with my now 18 year old C325BEE NAD amplifier. Thanks to paul_g_787, Kim Christensen and other readers I was able to repair it. My C325 switched off again after a few seconds after being switched on, so from amber to green and to amber light again. The ultimate cause was the SMD caps in the pre-Amps that may have leaked (C203/204/C103/104). I replaced all SMD caps with new ones, after which the amplifier switches on again without errors. Considering the age, I immediately recapped the entire power supply. It was a bit of a job, but for now the C325BGEE can last for a while. Thanks everyone !