Electrolux T5350 Service Manual page 104

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2. Replace the defective part.
21:4 NO COMMUNICATION
This error code is generated by the MCU for drum motor.
MCU detects there is there is a problem in communication with CPU.
Possible causes:
Bad contact in harness or connectors between CPU and MCU.
Recommended actions:
1. Check wiring, connections between CPU and MCU.
21:5 MOTOR SHORT CIRCIUT
This error code is generated by the MCU for drum motor.
The MCU reads the power consumption of the motor continuously. If the current for some reason exceeds a prede-
termined limit, the MCU will cut the current to the motor. After the motor has stopped (= tachometer indicates station-
ary motor), the MCU will attempt to restart it. If the MCU then detects high motor current again, this error code will be
activated. If on restarting after a first short circuit, the MCU rotates normally, the error code will not be shown.
Possible causes:
This error code can be activated for a number of reasons:
• Short circuit in motor. Measure motor windings with a Motor Tester.
• Short circuit internally in motor winding (impaired efficiency, higher current consumption).
• Short circuit in motor cables.
• Short circuit in connectors.
• Drops of water causing short circuits in the motor connector.
• Short circuit in the MCU output transistors.
• Bad contact in tacho signal.
• Bad contact in interlock signal.
Recommended actions:
1. If the error is a stable one, it is generally not difficult to locate the defective unit through resistance measurement
and testing with the service program. Measure motor windings with a Motor Tester.
2. Further information can be obtained by studying the contents of MCU ERROR LOG 1 and MCU ERROR LOG 2. Review
following:
SHORT CIRCUIT 2 (specifies how many times the error code has been active).
SHORT CIRCUIT 1 (specifies how many times the current limit has been exceeded. The difference between short
circuit 1 and short circuit 2 indicates how many times there has been a short circuit 1 that has not been confirmed
when restarting the motor).
LAST FAULT CODE N/8 (shows the 8 latest error codes).
TACHO ERR. LOW SPEED (can give a clue in case of intermittent errors).
TACHO ERR. HIGH SPEED (can give a clue in case of intermittent errors).
21:6 INTERLOCK HARDWARE
This error code is generated by the MCU for drum motor.
The MCU must be powered with 230V / 50 or 60 Hz on the interlock input in order to drive the motor. The interlock cir-
cuits in the MCU have been split into two channels so that a component error in MCU cannot give a false confirma-
tion that the door is locked. These two channels are checked against each other. If this check gives an incorrect
result this error code will be shown.
Possible cause:
The reason for this error code being activated can be attributed to an error in the interlock circuits in motor control.
Recommended actions:
1. Replace MCU.
21:7 LOW DC VOLTAGE
This error code is generated by the MCU for drum motor.
The MCU constantly measures the voltage over the mains input. If the voltage is below a predefined limit, the MCU
will shut off the current to the motor. Once the motor has stopped (= the tacho sensor indicates that the motor is
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