If you are experiencing issues and need replacement fuses, pls. send us a note at email@example.com. OK to use 400 - 500mA. Treat the power button on front of WA7tp as a standby ON/OFF switch. No need to flip the power switch on back of WA7 amp ON and OFF every time. Treat the flip switch as a main power ON/OFF. Use the flip switch when transporting unit or when on holiday and the amp will not be used for extended periods.