Mitsubishi Electric PURY-M200YNW-A1 Service Handbook page 205

[7-6 Error Code Definitions and Solutions: Codes [4000 - 4999] ]
7-6-11 Error Code [4129] Detail Code 103
1. Error code definition
Signal wire fault
2. Error definition and error detection method
Power supply signal not detected by control board.
3. Cause, check method and remedy
(1) Wiring fault
(2) PS board failure
32
- chapter 7
Cause Check method and remedy
Check the wiring between the following:
Between CN901 (MAIN board) and CN001 (PS
board)
Between CN902 (MAIN board) and CN002 (PS
board)
If none of the items described above is applicable,
and if the trouble reappears even after the power is
switched on again, replace the PS board.
BS_07_M