C0840 code on Kyocera 1128 MFP

[Supertech1]

We are experincing several C0840 codes on 1128's recently. We have tried firmware resetting the time and battery on the fax. Any help would be appreciated.

[White_Toner]

The manaul say: 0840 Faults of RTC
The time is judged to go back based on the comparison of the RTC time and the current time or five years or more have passed.
Defective control PWB.Replace the control PWB (See page 1-5-39).
The battery is disconnected from the control PWB. Check visually and remedy if necessary.

May be there is battery on the contol PWB, but not fax PWB?
What's mean "resetting firmware"? It is the same that upgrading?
Regards!

[quantum]

what to do with this error code c0840?