Egnater Renegade Needs Help

My Egnater Renegade stops working after 10-20 minutes. The amp loses all volume after approx. 10-20 minutes. The jewel light stays on. It will turn right back on if I reset the standby switch.I love the amp but cannot gig with it due to this problem. Please help. Thank You for your time, Marc

check the preamp tubes-

If it does it again, Jack your input guitar cord into the effects return jack

This should bypass the entire pre-amp section and go straight to the output tubes