No sound and red power light on NAD C372

I haven't talked to my dealer or NAD yet about this problem, but I wanted to check if anyone has had a similar issue with their NAD or could identify what's wrong. I usually leave the C372 powered up and on standby, but after powering down and unplugging the unit for a couple of days when I wasn't around, I powered it up again to find that it provides no sound from any source, into speakers or headphones. The power light glows its warning red, but I've checked all of the potential issues in the manual (speaker cable shorts, overheating, speakers selected, tape monitor not selected, etc.) and all of that's been OK. I powered it down, disconnected, checked, and reconnected everything, powered it up again and still the same thing. I've done this numerous times, tried different sources, and so forth. This happened once before, a few weeks ago, but when I powered down and up again it was fine. Any suggestions?

The amp is only a month old, and I'm using it with Vandersteen 2ce Signature IIs and Sennheiser HD 600s, with a Marantz changer, Playstation 1, and Technics TT as sources. Cabling is Tributaries and Monster. I've been very pleased with the amp and with my system's sound as a whole, and I've also owned other NAD integrateds (302, C325BEE) in the past without incident. Thanks for any input!