Classe Audio CAV-500, Service Manual

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PRO-SVR_LEGACY Page 7 of 13
Troubleshooting Guide
Symptom Possible cause
Unit won’t turn on Check connections;
Check fuses;
Check soft-start circuit;
Check relays;
Check power supply circuits (positive rail, negative rail)
Smoked and/or burned
components Check for short between components and ground;
Check output transistors;
Check power supply circuits (positive rail, negative rail).
Blown fuses Check for short between fuse and ground;
Check power supply circuits (positive rail, negative rail).
No output Check connexions;
Check output relays;
Check power supply circuits (positive rail, negative rail,);
Check output transistors.
Unit turn into protection Check for smoked and/or burned components;
Check power supply circuits (positive rail, negative rail,);
Check source and load;
Check protection circuit;
Check sensor wires between sensor PCB and control PCB;
Check outputs transistors and Mosfet drivers;
Perform updates, if necessary.
Excessive buzz and/or hum Check electrical lines;
Check for a ground loop in the system.
Oscillation Check source;
Check capacitors on main board;
Check 4.7
ƻ resistor.
Intermittent signal Check connections;
Replace shield wires.