Hillys0312

I have a SINUMERIK 840D NCU that loses data on switch off. New battery fan unit fitted. Tried a different back box and even a different NCU board. They both lose data on switch off with all LEDs lit. Any help would be greatly appreciated.

Hello,

Welcome to forum. Please open new topic for your query instead posting it in old topic.

Now your description is not clear. What I can understood is, data is lost. 

Have you fitted new fan & battery unit to old/prsent NCU box?

What do you mean by different back box & different NCU board?

Have you checked compatibility of NCU box & NCU board when you replaced those?

Please attach detail information of your NCU, NCU box along with snap shot of NCU 7 segment display & erro/fault message displayed on OP.

HTH