Yamaha R-S500 - Powering off while in use

Hi Guys,

I have a Yamaha R-S500 that is less that 1 year old and seems to power itself off randomly while in use.

It has happened while listening to music, watching movies at low and high volumes.

It is driving a pair of Pioneer CS-99A's.

I took the cover off and see nothing out of the ordinary. not a spec of dirt or dust. is not very humid or dusty.

What are simple things to check? This unit should still be under warranty but only seems to be faulting very rareely.. Like 1-2 months will go by before it will fault again and it is used daily.

Could it be a case of the unit thinking there is no signal and auto powering off?

I have only noticed this happening when I purchased a new sound card for my PC which is driving this system 99% of the time (Asus Xonar EssenceSTX - Using RCA connection)

Any insight would be appreciated. I have tried to include as much info that I can think of right now.

Could it be this:

http://faq.yamaha.com/us/en/article/audio-visual/hifi-components/stereo-receivers/r-s500/5131/7632

Doh! why didnt I think of that!

Unfortunately.. It's already off.

Can you put the old sound card back in and see if that cures the problem? I don't use an internal sound card any longer, and use the Behrenger UCA 222 external USB sound card. Very happy with the performance. It goes for around $30 .