NAD 317 trouble HELP

I have been having a problem with my NAD 317 amp. Seems that the left side of the power amp has an issue, where out of the clear blue sky, it makes a nasty static noise, and will eventually trip the protect circuit. The condition is independent of any setting, be it volume, input, etc. The real kicker is that I have had it in the shop (Saturday Audio) twice now, and the thing won't act up for them! Anyone else have a similar problem? What was the fix? Any hints would be GREAT! THANKS!
Better late than never... I am currently experiencing something similar: The left channel outputs static noise whenever the input is non-zero. I.e. pausing a CD removes the noise, but even the weakest input signal such as a quiet intro or "silence" in a DVD-movie triggers a cascade of white noise which is ubearable to listen to. It does not trip the protect circuit, though.

It's definitely not the speaker (switched them and even tried a different pair: the noise still appears in left channel). I've just had the amp on repair and they apparently could not reproduce the problem there. But they did replace some internal cables to fix something that was a known problem with the 317 (they said), except when I got home the static was still there...

I'm thinking maybe the noise is caused by radio-frequency spikes from other household appliances, either going by air and being picked up by the signal cables, or going through the power-grid in my apartment. That would explain why they didn't get the same in the shop. But why something like that should cause noise in the left channel only and not the right channel I really don't know...

If it's not something external as I'm guessing then it must be generated inside the amp by a faulty component, but then surely they would also have heard it in the shop?

Anyone suggestions?
Had a 317 for years, and never did something like that, so can't really help you. But you could try to separate the pre and power amp, at least you'll know in which amplifier stage the fault is. Maybe someone else can take it from there?
I seem to be experiencing a similar problem with my NAD C 340 amp. I notice that there is one particular song I listen to that causes the white noise/static. The protect circuit is tripped on this amp occasionally, but not very often. As you described, volume level and listening material do not seem to make a difference on tripping the protect circuit. The whole time I was listening today (with an NAD T 532 player and Triangle Antal XS speakers) I noticed that something just "wasn't right." Then eventually I heard the static in one song and knew that something wasn't right. There’s a possibility that it’s in the recording because I’ve only noticed this static in very few songs, and it’s reproduced very similarly each time. Immediately I assumed that it was the power line, but this may just be a cheap amp too. I also live in a townhouse complex, so my power may be more susceptible to line noise than someone living in a home. I was going to research power conditioners, but I won't spend more money on that than I did on this amp. The money would be better spent towards upgrading the amplifier. One thing I definitely noticed about this situation is that it sounds much better turned down low. It's as if the dirty AC power causes the sound to become very harsh at moderate levels. Anyone else have an opinion on this?