Toyotomi MTN-MTG A128FS Service Manual page 42

9.2.4 EEPROM parameter error diagnosis and solution
Shut off the power supply and turn on it 5s later
Replace indoor PCB
The problem comes out again
No
Is the EEPROM chip plugged in indoor PCB well? Correct the connection
Replace the main PCB of indoor unit
9.2.5 Zero crossing detection error
When such failure occurs, the main control board must have fault.
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