Loosing Time Setting on LS220D

[Robocop]

I have an LS220D and I keep getting a message that the time is not set correctly and do i want to use the computer time. I always say yes but next time it says the same again.

I assumed it must have a CMOS battery so I have tried to get into the case to have a look.

Does anybody recognise this problem and/or can you give me any guidance on fully dismantling the case?

(I also want to get into the case to remove the dust from the fan)

[1000001101000]

I've got some notes about how to disassemble that model as well as pictures of one taken apart here:
https://buffalonas.miraheze.org/wiki/Linkstation_LS220D

There's no battery to replace on these devices, I believe the main thing keeping time correct while it runs is NTP (though the SoC does have an RTC). Does this device have access to the internet?

[edkocol]

I have 2 LS220D units. Both are setup identically (sans ID and IP address). They both report firmware is up to date.

I can access both units on my LAN.

One retains the date time the other does not.  On the unit that does hold the date/time when I set the Name/Time/Language to "Use Default NTP" after saving the settings I am presented with the message: "Failed to Sync NTP server. Settings Saved". The message appears if I attempt to use the address: ntp.jst.mfeed.ad.jp instead of the default