Infinity Intermezzo 4.1t, Service Manual

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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.
INTERMEZZO 4.1t
21