Sakata SOB-50VA Service Manual page 101

Light Commercial R410A on-off
d. Outdoor unit malfunction
Whether the outdoor unit is power on
Measure whether the voltage of the communication line's red and black end
between the indoor and outdoor unit is +5V
Check the indoor unit main board CN5 or replace the main control board
e. EEPROM malfunction
EEPROM malfunction
EEPROM chip is broken
Check whether the main control chip 9177 is broken
Check PCB board or replace the main control board
Outdoor Units. Troubleshooting
Outdoor unit malfunction
Yes
Yes
Yes
Replace indoor PCB
No
No
No
Check when the power is on
No
Yes
Replace EEPROM
Yes
Replace 9177 chip
S13-01.01.13en
Replace the outdoor unit
board
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