The "Tape 1 Monitor" led on my C370 lights up spontanously without me activating it, and when I try to shut off the led by pressing the "Tape
1 Monitor" button it will only dimm a little, and I cannot get signal via any other inputs (CD, tuner and so on).
If I turn the amp off and on, the other inputs will work again, but the "Tape 1 Monitor" led is still on. After a while (hours or days) the led will go out by itself and the amp functions properly for a day or two; then the problem will occur again. I sent the amp to the local NAD-dealer here in Denmark (HI-FI Klubben) but they did not find a solution as the problem occurs now and then only