Beware of NAD M3 Fire Hazard

I will never purchase an NAD product again.

EVERY product suffers one-off failures.

NAD has made millions of units with very high reliability and excellent sonics for very reasonable prices.

NAD are well engineered. Electronics are made of component sourced from dozens of manufacturers. A dozen or more maybe involved in the power supply alone. All are potential points of failure for which NAD unjustly suffers the blame.

It's possible that a line surge coupled with a weakish part at precisely the wrong moment caused the only catastrophic failure on the planet.

The probability than another NAD unit would suffer a similar fate is small.

The unit is an audio computer and computers are replaced quite frequently.  The last firmware update was a decade ago, so the unit could be nearing EOL.

Some questions:
- did you buy it new?
- was the unit left on all the time?
- what is the local line voltage? 

The local line voltage is 110

The unit is rated 120v. Nominal is ±5% - 114v to 126v.

Running on 110v increases cap ripple if load high current delivery is required. Ripple increases heat. By chance did the unit smell hot?

Diodes usually fail open circuit

ESD often causes devices to fail as a short. A puddle of molten silicon makes an excellent conductor.

The only caps I've ever seen 'blow' have been due to reversed polarity. 

Failure analysis is often pure speculation... unless someone 'fesses up <:-0

Shaking down a supplier for a 10+ year old+ electronic product, with a history you don't know (not the first owner), that could have experienced surge events, or other events outside the suppliers control, is not cool.

 +1

As far as the voltage I am just guessing it is 110. I thought everyone is either 110 or 220

A G R E A T many devices today are still rated 117v. [NAD M3 is 120v]

120v became the US standard in 1967. 120v +5% is 126v which is 107.6% of 117v. It’s not much of an issue for solid state gear with regulated supplies, but in tube, particularly vintage, gear the extra volts can come very close to cap ratings. A Bucking Transformer to lower the voltage to rated is a handy toy. See http://www.ielogical.com/Audio/BuckTrans.php

It’s always a good idea to have a volt meter displaying voltage. A Kill-O-Watt or similar is close enough. Verify with a calibrated Fluke or similar.
D O N ’ T use is as a power meter, except for light loads and brief times.

Back in LA, we had line voltages meters in the studio. No point trying to record if the voltage was all over the map or dragging down to a brown out. Ditto listening to the HiFi.