Some general info:
Don't have the answer as to what the source of the error is.
But i will tell you that think other problems might provoke such a message....Being this is a new to you machine think investigation would be in order....
Power supply board problems can cause lots of faults....need to be sure that the NSV board (furthest to the right looking from the rear) has all the red LED's lit....
If not that is a starting point. NSV boars is quite repairable...Local member here does upgrades to latest factory specs on these......
Also the NCR (video) board can be an issue.....On my FP4NC it killed 3 video boards(rebuilt) in 5 years,before i bit the bullet and bought an LCD conversion.
That was some of the best money i ever spent on that machine......Been dead reliable since the replacement.
Best part is that the internal temp of the control has been lowered about 50*F with the change.....Better for the life of all those aging electronic components housed within.....
Further there are three battery packs used on that machine....If the 7.8v battery in the lower portion of the control is low or dead, the control likely will not start up...Possible to make things start if the control power is left on
for an extended period , say an hour or more...Some recharging of the battery is possible unless it is truly dead.
Further there is a battery on the memory board (NSP) that retains programs and software settings (like inch or meter) Possible to start the machine if this battery is dead, but can't retain any
saved info when powered down...
Finally there is a third battery on the NSV80 or NSV90 board (depends on which version "PC" the machine has, most likely this one is an NSV90)
Some info here:
https://www.practicalmachinist.com/...6/index3.html?highlight=Dialog+Battery+Change
See post #49
https://www.practicalmachinist.com/...not-start-up-329941/?highlight=SAFT+Batteries
Cheers Ross