Functional path
Ambient conditions
Air inlet/filter
Fan
Heatsink
Power terminals
DC capacitors
Control board
Keypad/fault history
Diagnostic signals and checkpoints
OvertemperatureIntermittent tripsFan noiseDust accumulationCapacitor bulge/leakCorroded terminals
Technician notes
- Maintenance evidence often explains intermittent undervoltage, overtemperature and nuisance trips.
- Fan life, blocked airflow and high cabinet temperature should be documented before board replacement.
- Loose power terminals can become destructive under load.