I have an older Techwood stereo system, one day while listening to it, the stereo just shut down. Now when the receiver, a Techwood STR84, is turned on, the screen displays "Welcome" and then "Protect", not allowing any function. I've tried unplugging it completely, waiting for over 30 minutes... That didn't help. I've used the 'Reset' button on the back panel... That didn't help either. Can someone please tell me what I need to do to correct this, so that I can use this receiver! I'm trying to avoid the costly repair shop!!! Maybe offer me a suggestion or a useful link, I would greatly appreciate your help!