Audio Systems: pioneeer stereo receiver, pioneer vsx, service engineer

Question
I have a pioneer vsx 49 tx it played grat for about 2 weeks then one day when i powered it up i got no audio whatsoever then later that night I turned it back on and it played beautifully.  I turned it off and went to work got back home turned it on and again no sound.  I had our service engineer  take it to his house and he got it to play fine again.  I got it back to my house and again no sound.  What could be causing this erratic pattern of one day it will play then the next day it doesn't??

Answer
There are many, many possible causes. It will require some investigations.   It could be something external to the receiver such as a bad line cord, bad breaker in the house, intermittent line feeding that part of the house, poor outlet/line cord connection.  In other words is the power to the receiver intermittent in any way?  Do the front panel lights come on? Or are the off when no audio?

Or, it could be something internal to the receiver such as a bad power  supply, bad audio power amp, any intermittent circuitry that feeds the audio to the output section of the receiver.

And, back to something external, if you are listening to a cd or mp3 player it could be that is the source of the problem, not the receiver.

So, do some noodling  and checking around to see if you can identify the likely place where the problem/cause may be.

Then, let me know more symptoms so I can help you narrow it down.

Hope this helps.
C