The overload problem is caused by the cooling fan not providing sufficient air flow. I had the same problem. It happened at relatively low sound levels. I removed the back cover and removed the fan. The receiver will go into overload the instant the fan is removed. I oiled the fan and reinstalled. I was able to play The Matrix at very high volume level with no problems. I am going to order a new fan. See WEB site http://www.partstore.com/GetModel.aspx?MfgName=Matsushita&BrandName=Panasonic&ModelNumber=SAGX650&PageSize=100&page=8#PartsearchSKUList

Part number: REM0020-1
FAN MOTOR UNIT, DC 0.1W .

This is the whole fan assembly, not just the motor. See fan assembly motor in "Technics SA-GX650 AV Control Stereo Receiver.pdf". Available on line for free. I wish you success.

Purdueman77