IL60

8)Connect the subwoofer amplifier to an AC power source; turn the unit ON. Measure the DC voltage at the “CD±wires; it should be 10-20 volts.

9)If it is 25 volts or greater, turn the amplifier OFF, disconnect from the power source, and replace: IL120S, IL60: Q504,Q507 IRF640 on the Power Supply PCB, Infinity part# QM0015.

IL50, IL100s: Q1 IRF540 on the Power Supply PCB, Infinity part# QM0020.

10)If the voltage is normal, turn the amplifier OFF, disconnect from the power source, and reconnect the “CD±” leads.

11)Finish reassembling the amplifier, remount the heatsink, replace the amplifier in the cabinet and test the subwoofer.

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Infinity IL60 L/R service manual