Mitsubishi Electric HP120TNU-A Service Handbook page 237

[7-9 Error Code Definitions and Solutions: Codes [7000 - 7999] ]
Error source
BC controller (1) Wiring fault
(2) Loose connectors, short-cir-
cuit, contact failure
(3) DIP SW setting error on the
control board
74
- chapter 7
Cause
1) Check the connector TYP1 on the control board.
2) Check the settings of SW4-1, SW5-7, and SW5-8 on the control board.
Check method and remedy
HWE18220_GB