Beware of NAD M3 Fire Hazard

ok... you probably got a simple case of defective cap.... most likely there is no more damage to the the unit . you need all 4 caps to be replaced and that is probably it ...  

@heaudio123, thank you for your response to my post. I know you are extremely knowledgeable about such matters, and my relevant design experience dates back a few decades.

I would be interested, though, in your comments about the section entitled "Operating Lifetime Model" on page 13 of the following Cornell Dubilier "Aluminum Electrolytic Capacitor Application Guide":

https://www.cde.com/resources/catalogs/AEappGUIDE.pdf

Based on the equations shown there it appears to me that operating such a capacitor at 50% of rated voltage would double "expected operating lifetime" compared to operating it at 90% of rated voltage, which to a close approximation is what is done in the M3.

Regards,
-- Al

I'd recommend, seriously, this time, not attempting to put resources into repairing it; When the electrolytic off-gassed and spewed its internal magic smoke, conductive fluid (electrolyte) went all over the other parts (IC's in particular) making new instantaneous conductive pathways and likely altering the nominal set points; It's any ones guess about the future reliability.

From a practical point of view, how relaxed would any of us be if the amp IS reworked? I sure as heck would not be able to enjoy music with this refurbished amp. I would be on edge...wondering when the next magic smoke makes an appearance;

It would be wonderful if NAD would pick up the tab on a proper failure analysis and next steps; 

BTW, I had an M3 in 2006 and really liked it; Very smooth and neutral; Beautiful to look at too; Impressive chassis design.

 

As an authorized NAD servicer for over 40 years this is the first time I’ve heard of this.
I can’t see how this would occur UNLESS the user keeps their electronics on all of the time.
The user did not mention they were listening the time it failed, so I guess they do keep it on at all times. In standby, the capacitor that failed is not in the circuit.
If powered to a fully on condition, the capacitor is live and before any regulation. If there are issues with incoming AC power they will translate thru to these 4 capacitors.
If the user does not keep the unit on at all times this can still occur, but it’s less of an issue.
Capacitors can and do fail due to many reasons but there is nothing endemic in this model.
If the incoming AC power is above the nominal voltage (typ. 114-126) for long periods of time, this can put a stress on filter caps in pre-regulated circuits.
Here is a good suggestion for all electronics... do not place anything combustible above the equipment and the "burning" component will not have anything to ignite.
I do agree with the poster directly above this as the highly corrosive electrolyte is likely spewed onto many parts and the PC board, too.  It will cause metal component leads as well as. PCB traces to corrode and fail. Also, the unit uses double sided PC boards and many small "plate-throughs" (micro rivets that connect one side of the board to the other) that are easily damaged from the electrolyte.