The RTC can provide a one off time to the M210, only if the clock has no time since power on. Setting Valid Time Off means that when the RTC loads the clock it is marked as 'Manual Time'; when Valid Time is On it is flagged as 'Valid Time', with a 4 minute timeout on the 'Loaded' flag. Changing the Valid Time menu setting after the RTC has loaded the M210 will not change the value of the M210's flag.
If the RTC Write Switch is on, the RTC time is updated with UTC once per minute from the M210 if 'Valid Time' is flagged. The RTC time can not be manually set.
The year value entered in the IRIG menu is used only at the point when a decoded IRIG time is loaded to the clock.
Time entry through the Configuration menu is not possible if the M210 'Valid Time' flag is set.
Suggested sequence to solve this problem:
If at point f the wrong year is applied there is one of two things going on: