Humax 9200t no clock display on stand by?

The clock display on standby has stopped displaying the time will only display ---- which means on standby it will not record reserved programs.When switched on it will display the time and record reserved programs ok .

We understand from Humax that it is a timer unit fault which requires renewing, has anyone fitted this item and would it be a self fit part rather than sending it to a repairer as the age of this PVR would make it uneconomical to send away for repair.