If your SF500 is not get the 30V of the power supply, and you get a voltage alarm on the front panel. Check the board E20147.1 located in the bottom of the SF Amplifier. Look for resistors R3 & R4. If they are burned replace R3 with 470ohm 1W and R4 with 100ohm 1W. After the resistor replacement, if the 30V is still missing, check the relay located on the board E30101-4*. Replace the relay if necessary. (* Some SFs do not have this board)

Please contact BEXT for further assistance.