The machining program cannot be saved after editing

Failure phenomenon: a CNC machine tool with a CNC system cannot process the program after editing
save.
Analysis and processing process: After many tests on site, it was found that the machine tool can be operated manually, handwheel, -8+, but
After editing the program and restarting after shutting down, it is found that the program is missing, but the system parameters still exist, so the bad battery can be ruled out
According to the preliminary diagnosis, the memory board may be damaged. Change with the same specification memory board on another machine
After the replacement, the machine tool returns to normal.