Power Transistor Overheat - Mitsubishi Heavy Industries KXZ Series Service Manual

Error code
E41(E51)
Remote control:
E41(E51)-1, 2*1
7-segment display:
*1 E41-1 (E51-1) : CM1, E41-2 (E51-2) : CM2 *2 E41-1 (E51-1) : 1-time flash, E41-2 (E51-2) : 2-time flash
1. Applicable model
Outdoor unit
2. Error detection method
E41 is displayed on 7-segment
LED.
3. Condition of error displayed
Anomalously high temperature
of power transistor is detected 5
times within 60 minutes (E41).
Or it is detected for 15 minutes
continuously (E51).
4. Presumable cause
• Power transistor anomaly
• Power transistor temperature
thermistor anomaly
• Inverter PCB anomaly
• Outdoor fan motor anomaly
• Anomalous cooling fan motor
for inverter
Note:
*1 Measuring position: Between + and – of C19
If it fails to repeat, connect the Mente PC, and continue to collect data.
LED Green Red
Keeps flashing Stays OFF
Indoor
*
Keeps flashing 2
Outdoor
5. Troubleshooting
Diagnosis
Save data for 30 minutes before stopping in Mente PC.
Have outdoor fans been running?
YES
Reset the power source, and restart.
Does it
repeat after restarting operation?
YES
Is 15V detected on inverter PCB?
(＊1)
YES
After power OFF
Is power transformer
attached properly? Check tightness of
screw, heat radiation silicon.
YES
101
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Content

Power transistor overheat

NO
NO
NO
NO
-
'14 • KX-SM-221
Countermeasure
Check, record operating condition.
Check power transistor
temperature.
Check operations of outdoor fan,
inverter cooling fan.
Repair according to the
troubleshooting E48.
Wait and see.
(Continue, if possible, and
record data.)
Measure after confirming
that 52X1 is turned ON.
Replace inverter PCB.
Coat power transistor with
silicon sufficiently, and fix
on radiator fin securely.
Replace power transistor.