As I said, it does it without anything connected (incl. speakers).That is usually caused by a short in one of the speakers. Try disconnecting them one by one to see when (if) it does finally power up. Keep the volume Down. When it does, that one has the problem.
That doesn't seem to work on this model. It's an older receiver that doesn't have an 'enter'. This shows pictures of it.That or an internal fuse/circuit breaker has switched. You may also need to do a full factory reset, which is typically accomplished by pressing and holding the power button for 5 seconds and a screen will appear with something like "Press Enter to Clear All", hit "enter" on the remote and it will then flush to factory settings. Just make sure you have written down all your configuration data like speaker distance settings, EQ settings, SPL level matching settings, etc., etc., before you do this since all of that will be removed.
You can download the service manual from here (it has the schematics and parts list)
You need to enter a code so the site knows it is a human asking for it. Also the .pdf comes up in an odd view, but Esc in Acrobat will put it back to a normal view in Adobe reader.
http://www.givemefile.net/smanuals/radios/sony/file/30453.html