Setting time on ROS4.39

Hi all,
Apologies for the off topic question.

One of my RiscPCs running 4.39 had lost its clock, but on rebooting it is not possible to set it to the current date & time.

Simplifying it, it is only possible to set it to 7:43pm Dec 25 2014.

Any ideas please ?

Elsewhere, Chris Evans said:

It is well known that RiscPC Clocks that have been stopped for months/years often fail to restart. IIRC all Arcs also use a PCF8583 RTC chip the same as in a RiscPC.

Some info here, perhaps: http://www.cjemicros.co.uk/blog/?p=110

Thanks for the reply Rick.
Unfortunately that doesn’t apply here (it’s been on since this time last year).
Once you have set the clock (to the above value) it does advance OK.
If you set the year to 2016 or 2017 it will sometimes actually set the year to 2015 or or 2016, but setting the day+month sticks at 25 Dec, and time is always 7:43pm.

Are you saying it always powers up with that date and time but *time shows it incrementing until you turn off or RESET?
If yes that would be expected if the date and time in the RTCs CMOS is not incrementing and not being able to change, it suggests the CMOS in the clock is no longer writeable. In that case either you need to change the RTC chip or bypass it with one of our podule based clocks listed in the blog rick linked to. e.g. http://www.cjemicros.co.uk/micros/individual/newprodpages/prodinfo.php?prodcode=CJE-RTCPOD
n.b. the date and or time is only ever read from the RTC on power up or on RESET. After that a ‘soft’ clock is used.