@tqcon possibly a shorted component or bad caps. Try a reset first.
Use this procedure to reset all the receiver's settings to the factory default. Use the front panel controls to do this.
1 Switch the receiver into standby.
2 While holding down the TONE button,press and hold the STANDBY/ON button for about three seconds.
3 When you see RESET? appear in the display, press ENTER .OK? shows in the display.
4 Press SYSTEM SETUP to confirm.OK appears in the display to indicate that the receiver has been reset to the factory default settings.
If that does not work you most likely have an issue with the power supply.
The only way to make determination is by you disassembling it and take a look at all the components (focus on the power supply). Post plenty of pictures with your question so we can see what you see.